Book of Abstracts - Chemie - Technische Universität Darmstadt

Transcription

37th FGMR Joint Discussion Meeting of the German and British Magnetic Resonance Societies and Priority Program 1601 Darmstadt, Germany September 7th to 10th, 2015 Impressum Technische Universität Darmstadt Karolinenplatz 5 64289 Darmstadt www.tu‐darmstadt.de Layout Michaela Fröhlich Sebastian Keuth Volker Schmidts Front page Reinhard Meusinger Volker Schmidts Printed by Sprintout Digitaldruck Grunewaldstr. 18 10823 Berlin 3 Contents 1. Sponsors and Exhibitors __________________________ 5 2. Organization ___________________________________ 6 3. General Information _____________________________ 8 4. Social Events __________________________________ 12 4.1. Leisure Program ______________________________ 13 5. Scientific Program ______________________________ 14 5.1. Tutorials ____________________________________ 14 5.2. Felix‐Bloch‐Lectureship 2015 ____________________ 14 5.3. Ernst Awards 2015 ____________________________ 15 5.4. Board & Members' Meetings ___________________ 16 6. Program Schedule ______________________________ 17 7. Abstracts _____________________________________ 25 7.1. Tutorials, Ernst Awards and Felix‐Bloch‐Lectureship _ 25 7.2. Plenary Lectures ______________________________ 33 7.3. Parallel Sessions ______________________________ 45 7.4. Poster Presentations _________________________ 103 8. Index of Contributors __________________________ 240 General Information
4 General Information
5 1. Sponsors and Exhibitors Financial support by sponsors and exhibitors is gratefully acknowledged: 
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ACD/Labs, Frankfurt, Germany ARMAR Chemicals AG, Döttingen, Switzerland Bruker BioSpin GmbH, Rheinstetten, Germany Cortec Net, Voisins‐Le‐Bretonneux, France Euriso‐top, SAS, Saint‐Aubin Cedex, France JEOL (Germany), Eching, Germany Magic Angle GmbH & Co. KG, Offenbach, Germany Magnettech GmbH, Berlin, Germany Magritek GmbH, Aachen, Germany Merck KGaA, Darmstadt, Germany Mestrelab Research S.L., Santiago de Compostela, Spain NMR Service GmbH, Erfurt, Germany Rototec‐Spintec, Griesheim, Germany Spektrino Sp.z o.o., Warsaw, Poland Spin‐Doc NMR Services, Schwerte, Germany Stelar s.r.l., Mede, Italy Furthermore, the organizers gratefully acknowledge the Deutsche Forschungsgemeinschaft, DFG, for supporting the 37th FGMR Joint Discussion Meeting of the German and British Magnetic Resonance Societies and Priority Program 1601. General Information
6 2. Organization Local Organization Christina M. Thiele (Chair) Volker Schmidts Michaela Fröhlich Sebastian Keuth Vera König Contact and Conference homepage info@fgmr2015 www.fgmr2015.de Scientific Committee Christina M. Thiele (Chair) Jochen Balbach Eike Brunner Gerd Buntkowsky Wolfgang Jahnke Frank Malz Reinhard Meusinger Gareth Morris Thomas Prisner Michael Reggelin Kay Saalwächter Graham Smith Cameron Tropea Michael Vogel Martin Vogtherr General Information
7 Ernst Award Committee Wolfgang Jahnke, Basel (Chair) Dariush Hinderberger, Mainz Alexej Jerschow, New York Herbert Kogler, Bremen Till Maurer, San Francisco Alfred Ross, Basel Kay Saalwächter, Halle (Saale) Heinz‐Jürgen Steinhoff, Osnabrück General Information
8 3. General Information Venue The Conference will take place in the “Hörsaal‐ und Medienzentrum” (HMZ, lecture hall building) at the Technische Universität Darmstadt, Campus Lichtwiese. Please have a look at the map below. Building L4|02 Hörsaal‐ und Medienzentrum (HMZ) Franziska‐Braun‐Straße 10 D‐64287 Darmstadt HMZ
General Information
9 Registration/Conference Office Registration will be open on Monday September 7th from 1 p.m. to 5 p.m. in the foyer of the lecture hall building. Afterwards, registration will only be possible in the conference office (HMZ ground floor, room 6). Opening hours conference office: Monday, Sept. 7th: 2 p.m. – 7 p.m. 8 a.m. – 6 p.m. Tuesday, Sept 8th: Wednesday, Sept. 9th: 8 a.m. – 6 p.m. Thursday, Sept 10th: 8 a.m. – 2 p.m. Email: [email protected] Opening hours wardrobe: You may store your personal belongings in a monitored room, accessible during all events. Speakers' room: A special "speakers' room" is available for preparation. General Information
10 Posters All posters shall be on display during the entire conference in the foyer of the lecture hall building (starting Tuesday morning). Posters can be mounted from Tuesday morning 8:00 a.m. and need to be removed by Thursday 1 p.m. Material to mount the posters will be provided in the foyer. The authors are requested to be at their poster during their scheduled poster sessions. Poster Session 1, Tue, 5 p.m. – 7 p.m. odd numbers Poster Session 2, Wed, 1:30 p.m. – 3:30 p.m. even numbers WiFi Eduroam / DFN‐Roaming The Technische Universität Darmstadt participates in the eduroam network. Members of other participating universities or research facilities may use their local network access. For all others it is possible to get a WiFi account at the conference office. Coffee and Lunch breaks Coffee, tea and water will be provided during the coffee breaks in the foyer of the lecture hall building. The university refectory (TU Mensa) is located just across the lecture hall building. On the first floor, you can get a buffet lunch for about € 5. On the ground floor of the same building, sandwiches, rolls and cakes as well as drinks are offered in our Bistro. They open at 8 a.m. and also offer breakfast. General Information
11 How to get there By Car: Parking is possible in the car parks (marked in blue on the map on page 8); parking fees are max. € 2,50 per day. By public transportation: Tickets for public transport are included in the conference ticket for the duration of the conference (7th to 10th of September). From Darmstadt Hauptbahnhof (main railway station) as well as the Maritim Konferenz Hotel: To get to Campus TU‐Lichtwiese by public transport, take the bus K to Lichtwiese/Mensa to the final stop TU Lichtwiese/Mensa, or the Odenwaldbahn (VIAS) to Darmstadt TU‐Lichtwiese Bahnhof. Every two hours, R 65 (Odenwaldbahn, VIAS) travels directly from Frankfurt Hauptbahnhof to Darmstadt TU‐Lichtwiese station in approximately 25 minutes From downtown Darmstadt/Luisenplatz or Schloß: Take the Bus K and exit at stop “TU Lichtwiese Mensa” (last stop). The lecture hall building (HMZ) is just opposite the bus stop. Alternatively, take tram no. 9 or 2 to “Böllenfalltor” and get off at the stop “Hochschulstadion”. From there it is a very nice walk of about 10 minutes. Please have a look at the map on page 8. For the Bus/Train schedule please check at: http://www.rmv.de/en/ As the bus is usually very crowded, we recommend also using the tram and enjoying a walk in the morning and evening. General Information
12 4. Social Events Welcome Mixer The welcome mixer will take place September 7th, 2015 starting at 7 p.m. (following the "Awards Session") in the foyer of the lecture hall building. Conference dinner The Conference Dinner will take place September 9th, 2015 at 7 p.m. in the Weststadt Bar, Mainzer Straße 106 in 64293 Darmstadt. www.weststadt.de Transportation to the location from the conference site via the Maritim Konferenz Hotel and Ibis Hotel is offered and included. Please have a look at the information slides and the information board for the departure time. Transportation from the Weststadt Bar to downtown Darmstadt will be offered at 10 and 11 p.m. General Information
13 4.1. Leisure Program Sightseeing in Darmstadt Darmstadt was a main center for Jugendstil (art nouveau) in Germany and is worth sightseeing any time a year. A guided tour to visit the interesting sights of the city of Darmstadt will be offered on Wednesday, Sep 9th and Thursday Sep 10th. Departure from the conference site on the 9th will be at 1 p.m. and you will be back at 4 p.m., on the 10th departure will be 12:30 p.m. and you will be back at 3:30 p.m. The tour itself will last about 2 hours. To take part you will need to pay € 3,‐. Please contact us during registration or anytime during the conference in the conference office. The number of tickets is limited to 24 persons each tour. Please make sure to wear comfortable shoes. Merck Company Visit We are happy to be able to offer you a Merck company visit on Thursday, Sep 10th. The tour is free of charge. Departure from the conference site will be 11:30 a.m. and you will be back at 5 p.m. The tour itself will last about 4 hours including lunch. Please note, as we have to register you at Merck, you need to get registered until Tuesday Sep 8th, 11 a.m. Please contact us during registration or in the conference office. The number of participants is limited to 29 persons. These safety regulations from Merck have to be followed:  Participants must carry valid identity papers with them  Please do not smoke or take photographs  Mobile phones and other electronic devices must be switched off  Please wear closed shoes and clothes that cover your shoulders and knees (e.g. trousers) Please note that for health reasons, pregnant women are not permitted to visit certain areas. General Information
14 5. Scientific Program 5.1. Tutorials These educational lectures on advanced magnetic resonance topics will take place on Monday, September 7th, 2015 beginning at 2 p.m. in the main lecture hall L4|02 2. Each lecture will be 45 min. “Distances from the NOE” David Neuhaus, Medical Research Council Laboratory of Molecular Biology, Cambridge “Distances from REDOR” Gerd Buntkowsky, Eduard‐Zintl‐Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt “Distances from DEER/PELDOR” Olav Schiemann, Physical and Theoretical Chemistry, Rheinische Friedrich‐Wilhelms‐Universität Bonn 5.2. Felix‐Bloch‐Lectureship 2015 Rasmus Linser Max‐Planck Institute for Biophysical Chemistry, Department NMR‐
Based Structural Biology, Göttingen “Protons as reporters on local chemical properties” Scientific Program
15 5.3. Ernst Awards 2015 Grit Sauer Eduard‐Zintl‐Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt „Effective PHIP Labeling of Bioactive Peptides Boosts the Intensity of the NMR Signal” G. Sauer, D. Nasu, D. Tietze, T. Gutmann, S. Englert, O. Avrutina, H. Kolmar, G. Buntkowsky Angew. Chem. Int. Ed. 2014, 53, 12941 – 12945. Dinar Abdullin Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich‐Wilhelms‐Universität Bonn “EPR‐Based Approach for the Localization of Paramagnetic Metal Ions in Biomolecules” D. Abdullin, N. Florin, G. Hagelueken, O. Schiemann Angew. Chem. Int. Ed. 2015, 54, 1827 – 1831. Aurélien Bornet Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) “Long‐Lived States of Magnetically Equivalent Spins Populated by Dissolution‐DNP and Revealed by Enzymatic Reactions” A. Bornet, X. Ji, D. Mammoli, B. Vuichoud, J. Milani, G. Bodenhausen, S. Jannin Chem. Eur. J. 2014, 20, 17113 – 17118. Scientific Program
16 5.4. Board & Members' Meetings FGMR Board Meeting The board of the FGMR will have a meeting on Monday, September 07th, 2015, at 2 p.m. in Alarich‐Weiss‐Str. 16, L2|07 Room 1. FGMR Members' Meeting The members of the FGMR will have a general assembly on Tuesday, September 08th, 2015, at 7 p.m. in L4|02 2. SPP 1601 Members' Meeting The members of the SPP 1601 will have a general meeting on Tuesday, September 08th, 2015, at 8 p.m. in L4|02 2. G‐NMR Meeting Members of the G‐NMR consortium are invited to a meeting on Thursday, September 10th, 2015, after the closing remarks of the conference (about 12.30 a.m.), in lecture hall L2|03 05. FGMR Small Molecules People interested in joining the FG “Small Molecules” are welcome. We'll meet on Thursday, September 10th, 2015, at 3 p.m. in L2|04 F2. Scientific Program
17 6. Program Schedule Program Schedule
18 Program Schedule
19 Program Schedule
* Royal Society of Chemistry NMR DG Postgraduate Meeting Prize Winner
20 Program Schedule
21 Program Schedule
* Royal Society of Chemistry NMR DG Postgraduate Meeting Prize Winner
22 Program Schedule
23 Program Schedule
25 7. Abstracts 7.1. Tutorials, Ernst Awards and Felix‐Bloch‐Lectureship Tutorials & Awards
26 Tutorial
Distances from the NOE
D. Neuhaus
David Neuhaus, [email protected]
MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge
Biomedical Campus, Cambridge CB2 0QH, U.K.
In this tutorial I will start by presenting the theory of the nuclear Overhauser effect
(NOE) for two spins in a rigid molecule, concentrating on the underlying concepts in a
largely non-mathematical treatment and explaining the fundamental differences
between NOEs observed in small, in large molecules and between molecules. From
this starting point, I will then discuss some of the main complications that arise in
multi-spin systems, particularly effects due to spin diffusion (relaying NOEs through
intermediate spins) and internal motions, and the limitations these impose on
interpretation. I will then discuss briefly some of the main approaches to deriving
structures from NOE information, concentrating on the case of protein structures.
Tutorials & Awards
27 Tutorial
Distances from REDOR
G. Buntkowsky1, H. Breitzke2
Gerd Buntkowsky, [email protected]
1, 2 Technische Universität Darmstadt, Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Darmstadt, Germany
Although there is a plethora of techniques for the measurement of distances via
magnetic dipolar interactions in solids under MAS conditions , there is one technique
which towers out of the mass, the Rotational Echo DOuble Resonance (REDOR)
experiment, devised by Gullion and Schäfer[1] a quarter of a century ago.
REDOR is a very robust technique for the determination of heteronuclear dipolar
interactions. While originally developed for measuring distances in organic and
bioorganic solids, employing pairs of spin-1/2 nuclei, in the meantime is has been
applied to both organic and inorganic systems and as a building block in more
complicated experiments.
The tutorial is split in two parts. In the first part and introduction into the theory and
application of REDOR is given, completed by some characteristic experimental
examples. In the second part, experimental demonstrations are given in our solid-state
NMR lab (note: the experimental demonstrations are limited to 3 groups a 15
participants).
[1] T. Gullion, J. Schaefer, J.Magn.Res. 1989, 81, 196; b)T. Gullion, J. Schaefer, Adv.
in Magn. and Opt. Res. Ed.W.S. Warren 1989, 13, 57.
Tutorials & Awards
28 Tutorial
Distances from DEER/PELDOR
O. Schiemann
Olav Schiemann, [email protected]
Institute of Physical and Theoretical Chemistry, Bonn, Germany
Material Sciences and Molecular Biology are engaging ever-larger molecular
structures. Thus, methods are needed that can provide structures and dynamics
information on the relevant length scale. Currently, approaches that combine
appropriate methods like e.g. X-ray crystallography, NMR, FRET, Molecular
Dynamics simulations and Electron Paramagnetic Resonance lead to very exciting
results.
In the tutorial, an Electron Paramagnetic Resonance method called Pulsed ElectronElectron Double Resonance (PELDOR or DEER) will be described. This method has
no limitation with respect to the size of the molecular complex and measures the
distance between spin centers on the nanometer scale (1.5 to 8nm) via the dipolar
coupling. Such spin centers can be intrinsic paramagnatic centers as e.g. metal ions or
semiquinones or artificially attached spin labels as e.g. nitroxide labels. It does enable
the generation of coarse-grained structures, provides angular information, permits the
counting of monomers in oligomers and gives access to the dynamics of the system
studied. The tutorial will discuss the advantages, limitations and perspective of the
method with a focus on the data analysis and interpretation. For a recent review of the
field see [1].
[1] C.R. Timmel, J.R. Harmer (Eds.) "Structural Information from Spin-Labels and
Intrinsic Paramagnetic Centers in the Biosciences" Struct. Bond. (2014), 152, 1-332.
Tutorials & Awards
29 Ernst Award
Effective PHIP Labeling of Bioactive Peptides
Boosts the Intensity of the NMR Signal
G. Sauer1, D. Nasu2, D. Tietze3, T. Gutmann4, S. Englert5, O. Avrutina6, H. Kolmar7,
G. Buntkowsky8
Grit Sauer, [email protected]
1, 3, 4, 8 Eduard-Zintl-Institut fuer Anorganische und Physikalische Chemie,
Technische Universitaet Darmstadt, Darmstadt, Germany
2, 5, 6, 7 Clemens-Schoepf-Institut fuer Organische Chemie und Biochemie,
Technische Universitaet Darmstadt
Magnetic Resonance applications are limited by the inherent low sensitivity caused by
the low population difference of the nuclear spin levels. Efforts were made to increase
this population difference, among them Para-Hydrogen-Induced Polarization
(PHIP).[1] This method is based on polarization transfer via a hydrogenation reaction
with para-enriched-H2. In fact an unsaturated moiety is needed which can be
efficiently hydrogenated with para-H2 in a pairwise manner. Due to this restriction a
small number of simple biorelated molecules have been studied to date using this
hyperpolarization method.[2-4]
The talk will present a short summary of my recent research based on the general
challenge to find structurally low invasive building blocks (including an unsaturated
moiety) to generate biomolecules for applications of PHIP. After getting first insights
towards the PHIP-susceptibility of exemplary unsaturated oligopeptides, an
unsaturated protease inhibitor is investigated as a first biologically active target for
PHIP. A series of novel bioactive derivatives of the sunflower trypsin inhibitor-1
(SFTI-1) suitable for hyperpolarization by PHIP are developed. The PHIP activity is
achieved by labeling with L-propargylglycine, O-propargyl-L-tyrosine, or 4-pentynoic
acid. 1H NMR signal enhancements of up to a factor of 70 is achieved in aqueous
solution.[5]
This systematic PHIP-study leads to the assumption that the propargyltyrosine residue
will find general application as an efficient, structurally low invasive building block to
selectively access PHIP in bioactive peptides.
[1] M. G. Pravica, D. P. Weitekamp, Chem. Phys. Lett. 1988, 145, 255-258
[2] M. Roth, A. Koch, P. Kindervater, J. Bargon, H. W. Spiess, K. Münnemann, J.
Magn. Reson. 2010, 204, 50-55
[3] S. Aime, W. Dastru, R. Gobetto, A. Viale, Org. Biomol. Chem. 2005, 3, 3948
[4] S. Gloeggler, J. Colell, S. Appelt, J.Magn. Reson. 2013, 235, 130 – 142
[5] G. Sauer, D. Nasu, D. Tietze, T. Gutmann, S. Englert, O. Avrutina, H. Kolmar, G.
Buntkowsky, Angew. Chem. 2014, 53, 12941-12945
Tutorials & Awards
30 Ernst Award
Trilateration of Paramagnetic Metal Ions in
Biomolecules
D. Abdullin1, N. Florin2, F. Duthie3, G. Hagelueken4, O. Schiemann5
Dinar Abdullin, [email protected]
1-5 Institute of Physical and Theoretical Chemistry, University of Bonn, Germany
Metal ions play an important role in the catalysis and folding of proteins and
oligonucleotides. Their localization within the three-dimensional fold of a
biomacromolecule is therefore an important aim in understanding structure-function
relationships. In the talk, a trilateration approach for the localization of paramagnetic
metal ions will be presented. The idea of the approach is that the position of a metal
ion in a biomolecular structure can be determined via distance constraints measured
between this ion and a number spin labels attached to the surface of the biomolecule
by site-directed spin labelling [1]. The attached spin labels are considered as reference
points in the molecular coordinate system of the biomolecule. The distance constraints
can be measured by one of the pulsed EPR techniques, such as pulsed electronelectron double resonance (PELDOR or DEER) [2] or relaxation-induced dipolar
modulation enhancement (RIDME) [3].
The approach was tested on the Cu(II) center of structurally well-characterized azurin
[4]. After site directed spin labelling of azurin with MTSSL at six different sites, six
Cu(II)/nitroxide distance constraints were measured by PELDOR and then used in the
home-written program mtsslTrilaterate [5] to locate the Cu(II) ion in the threedimensional fold of azurin. The error of the method of 2.6 Å was determined by
compassion with crystallographic data of azurin. The influence of distance errors,
number of constraints and starting structures on the trilateration result will be
discussed.
[1] C. Altenbach, T. Marti, H. Khorana, and W. Hubbell, Science 1990, 248, 10881092.
[2] A. D. Milov, K. M. Salikhov, and M. D. Shirov, Fiz. Tverd. Tela 1981, 23, 975982.
[3] L. V. Kulik, S. A. Dzuba, I. A. Grigoryev, and Y. D. Tsvetkov, Chem. Phys. Lett.
2001, 343, 315-324.
[4] D. Abdullin, N. Florin, G. Hagelueken, and O. Schiemann, Angew. Chem. Int. Ed.
2015, 54, 1827-1831.
[5] G. Hagelueken, D. Abdullin, R. Ward, and O. Schiemann, Mol. Phys. 2013, 111,
2757-2766.
Tutorials & Awards
31 Ernst Award
High Way to HELLS: Populating a Triplet Singlet
Imbalance on Equivalent Molecules by
Dissolution-DNP
A. Bornet1, X. Ji2, D. Mammoli3, B. Vuichoud4, J. Milani5, G. Bodenhausen6, S.
Jannin7
Aurélien Bornet, [email protected]
1-7 Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de
Lausanne (EPFL), Lausanne, Switzerland
Hyperpolarization by dissolution dynamic nuclear polarization (D-DNP) [1] offers a
way of enhancing NMR signals by up to five orders of magnitude in metabolites and
other small molecules. Unfortunately, hyperpolarization lifetimes are usually limited
to nuclear spin-lattice relaxation times. In some particular cases, these lifetimes can be
extended by storing the hyperpolarization in the form of long-lived states (LLS) [2]
that are immune to most dominant relaxation mechanisms. Levitt and co-workers have
shown how LLS can be prepared for a pair of inequivalent spins by D-DNP [3].
We have shown recently [4] that LLS in the form of a triplet-singlet imbalance (TSI)
can be created readily by D-DNP in molecules that contain two magnetically
equivalent spins in solution. Such an imbalance can have a lifetime TTSI much longer
than the longitudinal relaxation time T1. We baptized them Hyperpolarized Equivalent
LLS (HELLS). Like in para-hydrogen, a HELLS cannot be observed directly but can
be “revealed” by a chemical reaction that breaks the symmetry. For example, the
enzyme fumarase catalyzes the addition of D2O onto the double bond of fumarate
(-OOCCH=CHCOO-) to yield malate (-OOCCHDCHODCOO-). This addition
reaction breaks the magnetic equivalence of the two protons of the molecule, so that
the invisible HELLS of fumarate is converted into a hyperpolarized NMR signal of
malate.
[1] J.H. Ardenkjaer-Larsen, B. Fridlund, A. Gram, G. Hansson, L. Hansson, M.H.
Lerche, R. Servin, M. Thaning, & K. Golman, PNAS, (2003),100(18),10158-10163.
[2] M. H. Levitt, Annu. Rev. Phys. Chem.,(2012), 63, 89-105.
[3] M. C. D. Tayler, I. Marco-Rius, M. I. Kettunen, K. M. Brindle, M. H. Levitt, G.
Pileio, JAC S, (2012), 134, 7668-7671.
[4] Bornet, A.; Ji, X.; Mammoli, D.; Vuichoud, B.; Milani, J.; Bodenhausen, G.;
Jannin, S. Chem. Eur. J., (2014), 20, 17113 – 17118.
Tutorials & Awards
32 Felix-Bloch-Lectureship
Protons as reporters on local chemical properties
P. Rovó1, S.K. Vasa2, S. Xiang3, N. Kulminskaya4, K. Grohe5, K. Giller6, S. Becker7,
A. Kwan8, R. Linser9
Rasmus Linser, [email protected]
1- 7, 9 Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
8 School of Medical Sciences and School of Molecular Bioscience, University of
Sydney, Sydney, Australia
Protons have long been neglected as a carrier of chemical information in protein solidstate NMR. In accordance with solution NMR, however, great versatility and utility
are obvious if only appropriate means are employed to access protons despite their
strong dipolar couplings.
In recent years, we and others have developed preparative, technical and spectroscopic
means to treat protons as useful tools for structure, dynamics, and interactions. Our
group is now exploring the possibilities for utilization of protons in different
directions. As one example, protons are excellent reporters for long-distance restraints
for structure calculation. In combination with paramagnetic NMR, we demonstrate
that long-distance information in a range of more than 30 A can be obtained, which is
comparable for the first time to the situation in paramagnetic solution NMR.
Making use of fast Magic Angle Spinning and deuterated and 100% amide-back
exchanged proteins or even fully protonated samples, we have developed various
dedicated strategies towards backbone and sidechain resonance assignment and
employed them to different proteins of interest.
Using tailored spectroscopic techniques, we are even able to exploit aliphatic proton
chemical shifts in the absence of deuteration, which can be shown to be of general
significance for a plethora of spectroscopic concerns.
We believe that the exploitation of protons will play an important role in future solidstate NMR dealing with decreasing amounts and increasing complexity or
heterogeneity and hope that we can give you a little flavor here.
Tutorials & Awards
33 7.2. Plenary Lectures Plenary Lectures
34 Plenary Lectures 1
– no title given –
C.P. Grey
Clare Grey, [email protected]
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2
1EW, UK
no abstract provided.
Plenary Lectures
Clinical and Technical Applications of 4D-Flow
MRI
J. Hennig1, W. Buchenberg2, M. Menza3, U. Ludwig4, R. Lorenz5, J. Bock6, B. Jung7
Jürgen Hennig, [email protected]
1-6 University Medical Center Freiburg, Dept. of Radiology – Medical Physics,
Freiburg, Germany
7 Inselspital and University MR Center, Bern, Switzerland
Magnetic Resonance Imaging has become one of the main imaging techniques in
radiological practice, clinical and preclinical applications and research. In addition to
offer the possibility for non-invasive observation of a huge variety of pathologies,
MRI also allows to directly measure functional information. The possibility to directly
and quantitatively measure the velocity of moving spins by use of bipolar flow
encoding gradients has led to the development of 4D-Flow-MRI, in which a spatially
highly resolved dataset (typically with 3-dimensional spatial encoding) is acquired
with flow encoding in all 3 spatial dimensions. In order to follow arterial pulsatility
over the ECG-cycle, the measurement is performed with ECG gating. This allows
highly detailed study of hemodynamics in normal as well as in patients with relevant
pathologies (atherosclerosis, stenosis, thrombi, malformations, aneurysma,…). Flow
related parameters like wall shear stress and pressure are important parameters for risk
stratification in patients with pertinent disease.
In addition to clinical use, 4D-Flow MRI can also be used to study technical flow.
Compared to existing optical techniques it can be easily applied to opaque media and
allows a very efficient and comprehensive assessment of flow behavior in complex
systems with controlled variation of relevant parameters. In recent developments we
were able to combine flow measurements with simultaneous temperature mapping in
order to investigate heat exchange in flowing media.
[1] Markl M, Kilner PJ, Ebbers T. Comprehensive 4D velocity mapping of the heart
and great vessels by cardiovascular MR. J Cardiovasc Magn Reson. 2011;13:7.
[2] Grundmann S, Wassermann F, Lorenz R,et al. Experimental investigation of
helical structures in swirling flows. Int. J. for Heat and Fluid Flow 2012;
[3] Buchenberg, W., Wassermann, F., Grundmann, S., et al. Acquisition of 3D
temperature distributions in fluid flow using PRF thermometry. Magn.Reson.Med. in
press
Plenary Lectures
Engineering defects in diamond
M.W. Dale1, B.G. Breeze2, B.L. Green3, S. Onoda4, T. Oshima5, J. Isoya6, M.E.
Newton7
Mark Newton, [email protected]
1-3, 7 Department of Physics, University of Warwick, Coventry, UK
4, 5 Japan Atomic Energy Agency (JAEA), Takasaki, Japan
6 University of Tsukuba, Tsukuba, Japan
Defects in diamond have great potential for use as quantum sensors and qubits [1]. To
fully exploit their optical and spin properties necessitates that we control their
position, orientation and environment to optimise all of the desirable properties.
Electron paramagnetic resonance (EPR) and optical data will be presented on the
production and preferential orientation of defects in intrinsic diamond by electron
irradiated while subjected to a large uniaxial stress, and subsequently annealed under
uniaxial stress. Furthermore, a new probe will be described that has been designed to
apply up to 6 GPa of uniaxial stress on single crystal samples whilst simultaneously
performing both continuous wave and pulsed EPR experiments. In this probe a loop
gap resonator is used to obtain high EPR sensitivities for the small samples required to
obtain high pressures. Pressurised gas and a piston are used to apply stress to the
sample via quartz rods and diamond anvils. The probe is compatible with standard
variable temperature cryostats and has optical access to the sample.
New EPR data is presented using uniaxial stress to investigate both the reorientation
and the spin relaxation properties of single substitutional nitrogen centre (Ns0) in
diamond. It will be shown that uniaxial stress can be used to influence spin diffusion
and change spin-spin relaxation.
The authors gratefully acknowledge De Beers Technologies for financial support and
sample preparation. MWD and BGB acknowledge support from the EPSRC funded
Integrated Magnetic Resonance Centre for Doctoral Training.
[1] Doherty M W, Manson N B, Delaney P, Jelezko F, Wrachtrup J, and Hollenberg L
C L, Phys. Rep. 528 (2013), 1–45
Plenary Lectures
RNA-protein complexes in RNA metabolism: an
integrative structure biology approach
A. Lapinaite1, A. Marchanka2, B. Simon3, A. Graziadei4, T. Carlomagno5
Teresa Carlomagno, [email protected]
1- 5 EMBL, Heidelberg, Germany
During the biosynthesis and processing of the pre-rRNA and mRNA transcripts posttranscriptional modifications of ribonucleotides occur in functionally relevant regions.
In eukaryotes and archaea 2’-OH ribose methylation is carried out by the Box C/D
small nucleolar RNA-protein complex (s(no)RNP).
In the first part of the talk I will present the structure of the catalytically active Box
C/D sRNP complex in solution (390 kDa) assembled around a physiological sRNA
construct [1]. The structure is obtained by a powerful combination of solution state
NMR and small angle neutron scattering (SANS). We show that the active sRNP is a
pseudo-tetrameric complex: by solving the structure of both the apo- and the holocomplex we are able to decipher the mechanisms of methylation and to explain the
specificity of the enzyme. Furthermore, with an NMR detected activity assay we
reveal that the methylation at different rRNA sites is regulated, which in turns offer
implication for rRNA folding.
In the second part of the talk, I will present a novel strategy to determine the structure
of RNA by solid-state NMR. To date, substantial progresses have been made in the
structure determination of membrane proteins and amyloid fibrils, while significantly
fewer studies have addressed the structure of RNA or protein-RNA complexes (RNP)
by ssNMR. Nevertheless, the application of ssNMR to study large RNP complexes
holds excellent promises, due to the independence of the ssNMR line widths from the
molecular size. Here, we present the ssNMR-based structure of the 26mer box C/D
RNA [2].
[1] A. Lapinaite, B. Simon, L. Skjaerven, M. Rakwalska-Bange, F.Gabel, T.
Carlomagno (2013) Nature 502, 519-523
[2] A. Marchanka, B. Simon, G. Althoff-Ospelt, T. Carlomagno (2015) Nature
Communications, DOI: 10.1038/ncomms8024
Plenary Lectures
DNP-enhanced solid-state NMR on membrane
proteins
C. Glaubitz
Clemens Glaubitz, [email protected]
Institute of Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance
The advancement in structural biology of membrane proteins mainly due to
crystallography has created a great demand and offers also the opportunity of in-depth
spectroscopic studies to resolve functional mechanisms. In many cases, solid-state
NMR is the method of choice and recent advancements in dynamic nuclear
polarisation have broadened its applicability to towards cases, which have not been
accessible before (e.g. low spin numbers, lower populated intermediate states etc.).
The first part of this presentation will therefore provide an overview about recent
developments and applications of DNP-enhanced solid-state NMR to challenging
membrane proteins. Examples involve trapped intermediate states of
channelrhodopsin-2 [1], mapping of cross-protomer contacts in proteorhodopsin
complexes [2] and mechanistic details induced by small ligands bound to transport
proteins [3]. Practical aspects such as sample handling and doping with polarizing
agents will be discussed. Strategies of utilising hydrophobic radicals will be presented
[4] and novel experiments at the interface between solid- and liquid state NMR
towards high temperature DNP will be introduced [5].
In the second part of the presentation, it will be discussed how high-field and real-time
solid-state NMR approaches provide new mechanistic insight into the catalytic cycle
of ATP-driven (ABC) transporters.
[1] J. Becker-Baldus et al., PNAS (2015).
[2] J. Maciejko et al., JACS (2015), 137, 9032-9043.
[3] J. Mao et al., JACS (2014), 136, 17578-90.
[4] J. Mao et al., JACS (2013), 135, 19275-81.
[5] O. Jakdetchai et al., JACS (2014), 136, 15533-6.
Plenary Lectures
Recent progress in high-field EPR and ENDOR to
study biological proton-coupled electron transfer
M. Bennati
Marina Bennati, [email protected]
Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
Several fundamental biological processes, like photosynthesis or DNA biosynthesis,
involve translocation of electron and protons via formation of transient amino-acid
radical intermediates. The main difficulty in these studies is related to the transient
nature of these species and their low concentrations, often not amenable to advanced
EPR investigations. In Class I RNRs the catalytic mechanism involves a reversible
radical transfer across two protein subunits over an unprecedented distance of 3.5 nm.
Using a particular mutation strategy combined with pulsed 263 GHz spectroscopy we
could resolve the g-values of radical intermediates at three essential tyrosine residues
and detected a change in polarity from the most buried intermediate to the most
exposed one at the subunit interface. Moreover, 94-GHz 2H ENDOR allowed for
detection of a hydrogen bond network around each intermediate. Nevertheless the
acquisition of 94-GHz 2H ENDOR data required considerable signal averaging, which
motivated us to re-examine the method efficiency. The standard wide-spread ENDOR
experiment suffers from nuclear spin saturation when detecting slow relaxing nuclei.
To overcome the issue, we have introduced a sequence reminiscent of the HartmannHahn experiment in solid state NMR, in which two spins are concomitantly irradiated
to match their energy splitting. For electron and nuclear spins, the largely different
gyromagnetic ratios can be compensated by the hyperfine coupling and a proper
choice of resonance offsets. Performance and application potential of this experiment
are presented.
Plenary Lectures
Long-lived spin states: breaking the T1 limit in
solution NMR
M.H. Levitt
Malcolm H. Levitt, [email protected]
School of Chemistry, University of Southampton, SO17 1BJ UK.
Long-lived states are configurations of nuclear spins that display long relaxation
times, relative to ordinary nuclear magnetization. A primary example is the state of
singlet order in a pair of spins-1/2, defined as the mean population difference between
the spin-0 singlet state and the spin-1 triplet state. In favourable circumstances the
lifetime of nuclear singlet order may exceed that of longitudinal magnetization by a
factor of 50 or more. Singlet order does not itself provide an NMR signal but it is
possible to convert magnetization into singlet spin order, and back again, providing
that a small symmetry-breaking mechanism is provided (rather like the keyhole in a
safe).
We have used molecular dynamics, quantum chemistry and spin dynamical theory to
guide the design of molecular systems providing exceptionally long-lived singlet
order. Target systems could then be synthesised through a collaboration with synthetic
organic chemists. An example will be given of a molecular system that exhibits a
nuclear singlet lifetime of more than 1 hour in a room-temperature liquid.
Systems of this kind hold promise as transport agents for nuclear hyperpolarization
and for molecular sensing and imaging applications.
Long-lived states are not restricted to two-spin systems. If time permits, some
experiments on long-lived states in the three-proton systems of methyl groups will
also be presented.
Plenary Lectures
Using parahydrogen to sensitise MR detection
S.B. Duckett
Simon B. Duckett, [email protected]
Department of Chemistry, University of York, York, UK
In the Centre for Magnetic Resonance in York, we are seeking to develop
hyperpolarised MR methods that use parahydrogen [1] as a latent source of
hyperpolarisation to improve MR sensitivity.
Recently, we developed a pump-probe time-resolved technique to track rapid chemical
change by following a hyperpolarised MR signal.[2] We do this by employing a metal
dihydride complex which undergoes photochemical reductive elimination of H2. This
is followed by the addition of parahydrogen which acts to prepare a reaction product
in a precisely defined hyperpolarized nuclear spin-state. We then investigate the timeevolution of this state as a function of a delay that is introduced between the initial
laser excitation step and the final NMR observation set. As a result we see signal
oscillations that encode the magnetic properties of the complex and the rate of the
product forming step. I will discuss the basis of these results and link them through to
the signal amplification by reversible exchange (SABRE) processes.[3] SABRE
hyperpolarises a target molecule (the contrast agent) using a reversible exchange
reaction involving the contrast agent, parahydrogen and a polarisation transfer
catalyst. I will describe the basis of SABRE and illustrate how it can be optimised. I
will finish by discussing our progress towards achieving viable MRI contrast agents
through SABRE.
[1] Duckett, S. B. & Mewis, R. E. Application of Parahydrogen Induced Polarization
Techniques in NMR Spectroscopy and Imaging. Acc. Chem. Res. 2012 (45) 12471257.
[2] Torres, O.; Procacci, B.; Halse, M. E.; Adams, R. W.; Blazina, D.; Duckett, S. B.;
Eguillor, B.; Green, R. A.; Perutz, R. N.; and Williamson, D. C., Photochemical pump
and NMR probe: chemically created NMR coherence on a microsecond timescale, J.
Am. Chem. Soc., 2014 (136) 10124-10131.
[3] Adams, R. W. et al. Reversible Interactions with para-Hydrogen Enhance NMR
Sensitivity by Polarization Transfer, Science, 2009 (323) 1708-1711.
Plenary Lectures
Pure Shift NMR: Recent Advances and
Applications
G.A. Morris
Gareth A. Morris, [email protected]
School of Chemistry, University of Manchester, UK
Spin-spin coupling is simultaneously one of the most fruitful sources of structural
information in NMR, and one of the biggest obstacles to the extraction of such
information. Couplings carry a wealth of information about structure, stereochemistry
and electronic environment, but the multiplet structure they cause limits spectral
resolution to the extent that almost all 1D proton spectra show overlapping multiplets,
and many are partly or wholly unresolved.
The resolution of this paradox is, in principle, straightforward: design experiments
that switch off the effects of coupling when resolution is needed, but restore them
when coupling information is required. The need for such methods was articulated as
early as 1960, by Ernst and Primas, but until recently general and practical techniques
for broadband homonuclear decoupling have been slow to emerge.
A variety of experiments are now available for measuring “pure shift” spectra, i.e.
spectra in which all homonuclear couplings are inactive. The different mechanisms
and underlying principles involved will be described, practical results and applications
compared, and some recent developments and extensions presented [1-4].
[1] M. Foroozandeh, R.W. Adams, N. Meharry, D. Jeannerat, M. Nilsson and G.A.
Morris, Angew. Chem. Int. Ed. (2014), 53, 6990.
[2] M. Foroozandeh, R.W. Adams, M. Nilsson and G.A. Morris, J. Am Chem Soc.
(2014), 136, 11867.
[3] L. Kaltschnee, A. Kolmer, I. Timári, V. Schmidts, R.W. Adams, M. Nilsson, K.E.
Kövér, G. A. Morris and C.M. Thiele, Chem. Commun. (2014), 50, 15702.
[4] I. Timári, T.Z. Illyés, R.W. Adams, M. Nilsson, G.A. Morris and K.E. Kövér.
Chem. Eur. J. (2015), 21, 3472.
Plenary Lectures
Optimum Control and Visualization of Spin
Dynamics in Magnetic Resonance
S.J. Glaser
Steffen J. Glaser, [email protected]
Department of Chemistry, TU München, Garching, Germany
Optimal Control Theory offers powerful analytical and numerical tools to design pulse
sequences and to explore their performance limits. These tools have not only provided
pulse sequences of unprecedented quality and capabilities, but also new analytical and
geometrical insight and a deeper understanding of pulse design problems. Efficient
numerical algorithms, such as the GRAPE algorithm [1], make it possible to develop
robust time-optimal or relaxation-optimized pulse sequences, taking into account
experimental limitations and imperfections, such as maximum pulse amplitudes,
maximum pulse power, pulse inhomogeneity as well as transient effects associated
with the switching of pulse amplitudes and phases. Examples will be shown for
applications in NMR and EPR spectroscopy, including broadband pulses and
heteronuclear decoupling sequences [2,3]. In addition to individually optimized
pulses, simultaneously optimized cooperative (COOP) pulses provide significant
performance gains by exploiting additional degrees of freedom [4]. Novel cooperative
pulses will be presented for broadband Hahn echo experiments.
Finally, new ways to look at pulses [5] and their effects on spin systems will be
discussed. The DROPS representation of spin operators [6] provides an intuitive and
general way to visualize the dynamics of coupled spins and its implementation in the
SpinDrops app makes it possible to interactively design and analyze pulse sequences.
[1] N. Khaneja, T. Reiss, C. Kehlet, T. Schulte-Herbrüggen, S.J. Glaser, JMR 172,
296-305 (2005).
[2] M. Lapert, E. Assémat, S.J. Glaser, D. Sugny, J. Chem. Phys. 142, 044202 (2015).
[3] F. Schilling, L.R. Warner, N.I. Gershenzon, T.E. Skinner, M. Sattler, S.J. Glaser,
Angew. Chem. 53, 4475-4479 (2014).
[4] M. Braun, S.J. Glaser, New J. Phys. 16, 115002 (2014).
[5] S.S. Köcher, T. Heydenreich, S.J. Glaser, JMR 249, 63-71 (2014).
[6] A. Garon, R. Zeier, S.J. Glaser, PRA 91, 042122 (2015)
Plenary Lectures
45 7.3. Parallel Sessions Parallel Sessions
46 Parallel Session 1
Diving into the unknown: using solid-state NMR to
understand the molecular structure of tissues
M.J. Duer
Melinda J. Duer, [email protected]
Dept of Chemistry, University of Cambridge, UK
The extracellular matrix forms the bulk of our structural tissues. At a molecular level,
it provides the scaffold which supports cells and essential signalling pathways, as well
as underpinning the mechanical properties of our tissues. However, understanding the
molecular level properties of the extracellular matrix has been hampered by the lack of
methods to study tissues at the atomic scale.
Here we show that using
multidimensional solid-state correlation NMR spectra (13C-13C, 13C-15N) from
“heavy” mouse tissues to map the underlying molecular structures in native tissues
allows us to develop laboratory-grown tissues that can be shown to have very similar
molecular structures to native tissues, and thus represent demonstrably good models of
native tissue. The refined laboratory-grown tissues can then be manipulated by
growing them with isotope labels in specific components to allow detailed study of
structure and possibly function of the various extracellular matrix components. This
talk will illustrate this approach by detailing how it has led to new insight into tissue
calcification and ageing in particular, as well as an understanding for the first time of
extracellular matrix components such as collagen glycosylation.
Parallel Sessions
Application of High-Field Solid-State NMR to
Pharmaceuticals, Supramolecular Self-Assembly
and Plant Cell Walls
S.P. Brown
Steven P. Brown, [email protected]
Department of Physics, University of Warwick, Coventry, UK
Applications of advanced solid-state NMR methods for probing intermolecular
interactions, notably hydrogen bonding are presented, with two-dimensional highresolution 1H experiments [1] being shown to be particularly powerful. Homonuclear
1
H-1H double-quantum (DQ) experiments reveal proximities (typically under 3.5
Angstroms) among pairs of hydrogen atoms, for example identifying an anhydrous or
hydrate form of an active pharmaceutical ingredient in a tablet formulation [2] or
distinguishing between ribbon-like or quartet-like self assembly in guanosine
supramolecular structures [3,4]. 14N-1H spectra show one-bond NH connectivities or
additionally longer-range NH proximities depending on the recoupling time
employed. Applications to guanosine self assembly [3,4] and proving molecular level
mixing in co-crystals [5,6] and an amorphous dispersion [6] are shown. Recent results
applying 1H-decoupled 11B MAS NMR to probe metal-templated guanosine quartet
formation in a guanosine-borate hydrogel [7] as well as 13C refocused INADEQUATE
spectra to characterize biopolymer interactions in plant cell walls will also be
presented [8].
[1] Brown, S. P. Solid State Nucl. Magn. Reson. 2012, 41, 1.
[2] Griffin, J. M.; Martin D. R. and Brown, S. P. Angew. Chem. Int. Ed. Engl. 2007,
46, 8036.
[3] Webber, A. L.et al J. Am. Chem. Soc. 2011, 133, 19777.
[4] Reddy, G. N. M. et al Solid State Nucl. Magn. Reson. 2015, 65, 41.
[5] Maruyoshi, K. et al Chem. Commun. 2012, 48, 10844.
[6] Tatton, A. S. et al Mol. Pharm. 2013, 10, 999.
[7] Peters, G. M. et al J. Am. Chem. Soc. 2014, 136, 12596.
[8] Dupree, R. et al Biochemistry 2015 , 54, 2335.
Parallel Sessions
Interface-selective solid-state NMR in hybrid
materials
U. Scheler
Ulrich Scheler, [email protected]
Leibniz-Institut für Polymerforschung Dresden e.V.
The interface between the organic and the inorganic component in hybrid materials,
which can be biomaterials like bone or polymer composites, determines properties and
functions.
To study molecular dynamics in thin polymer films, relaxation NMR combined with
CRAMPS detection provides resolution to identify functional groups and to separate
solvent signals. The molecular dynamics and swelling in polymer brushes is much
faster than in bulk polymers.
Selective excitation at the interface is achieved by trans-interface magnetization
transfer like fluorine-proton cross polarization has been applied on polyelectrolyte
multilayers on a Nafion film. Spin diffusion spreads the magnetization. Thus the
gradient of structure or molecular mobility in the polymer from the surface to the bulk
is probed. Selective excitation and relaxation as demonstrated in nanoparticles from
hydroxyapatite.
The OH signal is selectively excited by a chemical-shift selective spin echo, which
benefits from the narrow linewidth of the OH signal. Then the magnetization is spread
out by spin diffusion. The particles had been coated by polylelectrolyte multilayers
and PSS as the outermost layer which is identified in the spectrum and can thus be
used as a ruler. The selectivity is compared to solid-state DNP experiments in which
spin-labeled polymers are used.
After establishing the techniques on model systems, it has been applied to realistic
particle-filled polymer systems and biomimetic hydroxyapatite-gelatine nanoparticles.
Parallel Sessions
Enhanced local 1H spin diffusion by moderate
MAS
M. Roos1, P. Micke2, K. Saalwächter3, G. Hempel4
Günter Hempel, [email protected]
1, 3, 4 Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
2 Max-Planck-Institut für Kernphysik, Heidelberg, Germany
Proton NMR spin-diffusion experiments are often combined with magic-angle
spinning (MAS) to achieve higher spectral resolution of solid samples. Here we show
that local proton spin diffusion can indeed become faster at low (<10 kHz) spinning
rates as compared to static conditions. This is due to the modulation of the orientationdependent dipolar couplings during sample rotation. Spin diffusion under static
conditions can thus be slower than the often referred value of 0.8 nm²/ms, which was
determined using slow MAS [1].
The amplification of spin diffusion by slow MAS cannot be explained by any model
based on independent spin pairs; at least three spins have to be considered. In spin
pairs the MAS effect can only reduce the dipolar interaction and therefore the spin
diffusivity; there is no possibility for enhancement. The eight levels of a three-spin
system, however, are varying in height by rotation. This enables level crossings during
the sample rotation. A second way of explanation is based on density-matrix
calculations which imply the truncation of binary dipolar couplings by the existence of
a third spin which is differently coupled to the both paired spins. Third, we performed
numerical calculations with the program SPINEVOLUTION. They also confirm the
possible enhancement of polarization exchange by slow MAS in three-spin systems.
[1] J. Clauss, K. Schmidt-Rohr, and H. W. Spiess. Acta Polym. (1993), 44, 1
Parallel Sessions
Towards In-Vivo Histology using Magnetic
Resonance Imaging (MRI)
N. Weiskopf
Nikolaus Weiskopf, [email protected]
Wellcome Trust Centre for Neuroimaging, UCL, London, UK
Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
Understanding the normal and diseased human brain crucially depends on reliable
knowledge of its anatomical microstructure and functional micro-organization (e.g.,
cortical layers and columns of 200-1000µm dimension). Even small changes in this
microstructure can cause debilitating diseases. Until now, the microstructure can only
be reliably determined using invasive methods, e.g., ex-vivo histology. This limits
neuroscience, clinical research and diagnosis.
The presentation will discuss how an interdisciplinary approach developing novel
MRI acquisition methods, image processing methods and integrated biophysical
models aims to achieve quantitative histological measures of brain tissue, leading to
the emerging field of in vivo histology using MRI (hMRI; [1]). The talk will cover the
challenges of hMRI and different milestones on the path towards this goal including
recent methodological advances in quantitative MRI [2] and related biophysical
modelling. As an example application we will focus on the characterization of cortical
myelination and its relation to brain function [3]. The presentation will conclude with
an outlook on future developments, applications and the potential impact of in-vivo
histology using MRI.
[1] Weiskopf, N., Mohammadi, S., Lutti, A. & Callaghan, M. F. Advances in MRIbased computational neuroanatomy: from morphometry to in-vivo histology. Curr.
Opin. Neurol. 28, 313–322 (2015).
[2] Weiskopf, N. et al. Quantitative multi-parameter mapping of R1, PD*, MT, and
R2* at 3T: a multi-center validation. Front. Neurosci. 7, 95 (2013).
[3] Dick, F. et al. In vivo functional and myeloarchitectonic mapping of human
primary auditory areas. Journal of Neuroscience 32, 16095–105 (2012).
Parallel Sessions
Magnetic resonance measurements of flow and
phase behaviour in multi-phase reactors
A.J. Sederman
Andy J. Sederman, [email protected]
Magnetic Resonance Research Centre, Department of Chemical Engineering and
Biotechnology, University of Cambridge, UK
Magnetic Resonance methods are most commonly associated with medical MRI and
for use as an analytical spectroscopy tool; however its infinite flexibility has led to it
being applied in a wide range of other areas. This flexibility makes Magnetic
Resonance (MR) an ideal measurement method for investigating problems in chemical
engineering where non-invasive local measurements of velocity, diffusion,
concentration or NMR relaxation can provide useful information, though working
with engineering systems will usually bring its own MR measurement complications.
This talk will focus on some of the MR challenges that have to be overcome in order
to provide quantitative data on the required timescales in reaction engineering
samples. Gas/liquid/solid three-phase reactors are widely used for reactions such as
desulphurisation, hydrogenation and oxidation but an understanding of the mass
transport between these phases within these reactors is limited. We have used MR
imaging and spectroscopy to elucidate mass transport and reaction mechanisms at
realistic reactor temperatures and pressures. In these experiments, it is necessary to
quantitatively identify phase behaviour and chemical species. In gas-liquid bubbly
flows, the phase distribution is highly time dependent and here imaging speed is
important and non-linear sparse sampling can be used to obtain the timescales
required.
Parallel Sessions
MRI Techniques for Thermofluids Engineering
F. Wassermann1, B. Buchenberg2, B. Jung3, R. Simpson4, C. Tropea5, S. Grundmann6
Florian Wassermann, [email protected]
1- 3, 5 Department of Fluid Mechanics and Aerodynamics, Technische Universität
Darmstadt, Darmstadt, Germany
2, 4 Department of Radiology/Medical Physics, University Medical Center Freiburg,
Freiburg, Germany
3 University Hospital, Institute of Diagnostic, Interventional and Pediatric Radiology,
Bern, Switzerland
6 Department of Fluid Mechanics, University of Rostock, Rostock, Germany
Magnetic resonance imaging (MRI) techniques for the acquisition of flow quantities,
such as velocity, concentration, turbulence and temperature have been established as a
potential measurement technique for many fluid mechanical applications over the last
years [1].
Measuring three-dimensional temperature fields (magnetic resonance thermometry MRT) simultaneously with three-dimensional three-component velocity fields
(magnetic resonance velocimetry - MRV) is the goal of a DFG-funded joint research
project at Technische Universität Darmstadt and the University Medical Center
Freiburg. The most advanced and promising MRT method is based the proton
resonance frequency (PRF) shift of the water molecule [2].
This work aimed to investigate the temperature and velocity distributions in a
countercurrent double pipe heat exchanger [3]. The flow model consists of two
concentrically aligned pipes. The outer pipe is made of Plexiglas. The inner pipe is
made of copper. Both pipes form an annulus through which the measurement fluid is
flowing. Water is pumped through the inner pipe. A temperature distribution is
obtained in the annulus by unbalancing the inlet fluid temperatures into the inner and
outer pipe flow. Strong buoyancy forces are evoked in the annulus flow. This leads to
the formation of three-dimensional temperature structures in combination with the
formation of a secondary flow system. This novel experimental approach and the
results achieved with MRT and MRV are presented.
[1] C. Elkins and M. Alley, Exp. Fluids (2007), 43(6):823–858.
[2] V. Rieke and K. Butts Pauly, J. Magn. Reson. Im. (2008), 27(2):376-90.
[3] W. B. Buchenberg, F. Wassermann, S. Grundmann, B. Jung and R. Simpson,
under review J. Magn. Reson. Med. (2015).
Parallel Sessions
Improved electrophoretic NMR – A systematic
study comparing ionic transference numbers in
Ionic Liquids
M. Gouverneur1, J. Kopp2, L. van Wüllen3, M. Schönhoff4
Monika Schönhoff, [email protected]
1, 2, 4 Institute of Physical Chemistry, University of Muenster, Münster, Germany
3 Institute of Physics, University of Augsburg, Augsburg, Germany
Ion transport in Ionic Liquids (IL) is very important for their application in energy
storage devices [1]. Diffusion, conductivity and viscosity are commonly determined
quantities; however, they can not quantify the contribution of a specific ion species to
the conductivity. This information is contained in the electrophoretic mobility, which
needs to be known to determine ionic transference numbers.
Electrophoretic NMR (eNMR), based on the application of a voltage during a pulsed
field gradient NMR experiment, is one of the few methods to measure mobilities for
non-metal ions, and it has been mainly applied to dilute salt solutions [2]. The
investigation of highly conductive liquids such as IL is difficult due resistive heating
of the sample inducing convection [3]. So far, only two IL mobilities in the range of
10-9 m2/Vs could be determined [4].
Here we employ a self-built eNMR electrode configuration and generator developed
for highly conductive samples. With this setup we show for the first time a systematic
mobility study of seven different IL in the range down to 10-10 m2/Vs. Cation and
anion (1H, 19F, rsp.) mobilities depend strongly on molecular structure and increase for
cations with shorter alkyl residues, and enhanced delocalization of the positive charge,
which weakens the ion-ion interaction in the IL. The comparison of the electrophoretic
mobilities with self-diffusion coefficients provides insights in the intermolecular
dynamics, in particular into the relevance of asymmetric ionic clusters.
[1] M. Armand, F. Endres, D. R. MacFarlane, H. Ohno, B. Scrosati, Nature Mater., 8,
621, 2009.
[2] M. Holz, Chem. Soc. Rev. 23, 16, 1994.
[3] F. Hallberg, I. Furo, P. V. Yushmanov, and P. Stilbs, J. Magn. Reson. 192, 69,
2008.
[4] Z. Zhang, L. Madsen, J. Chem. Phys. 140, 84204, 2014.
Parallel Sessions
Purcell-enhanced relaxation of electron spins
A. Bienfait1, J.J. Pla2, Y. Kubo3, X. Zhou4, K. Moelmer5, T. Schenkel6, D. Vion7,
D. Esteve8, J.J.L. Morton9, P. Bertet10
John Morton, [email protected]
1, 3, 4, 7, 8, 10 Quantronics group, SPEC (CNRS URA 2464), IRAMIS, DSM, Gifsur-Yvette, France
2, 9 London Centre for Nanotechnology, University College London, UK
5 Department of Physics and Astronomy, Aarhus University, Aarhus C, Denmark
6 Accelerator and Fusion Research Division, Lawrence Berkeley National Laboratory,
Berkeley, California, USA
Observing spontaneous emission in spins is challenging. Nuclear spins in 800 MHz
NMR exhibit a free space spontaneous emission rate of ~1E-22 /s, while for electron
spins at a typical X-band frequency this rate is ~1E-12 /s. Spontaneous emission
therefore presents a negligible contribution to the spin relaxation time T1, which is
instead driven by a variety of other processes, such as spin-phonon interactions. When
a two-level system is placed in a resonant cavity, spontaneous emission is enhanced
through the Purcell effect [1], which has been observed for several decades for optical
transitions in a variety of atomic and solid state systems [2]. Nevertheless, for typical
cavity Q-factors and mode volumes in conventional ESR, even this enhanced
relaxation rate remains on the order of 1/year.
By coupling an ensemble of Bi donors in Si to a 7.3 GHz micron-scale
superconducting resonator with Q > 100,000, we achieve a Purcell-enhanced
relaxation rate of up to 3 Hz, well in excess of the natural spin relaxation rate of this
system (observed to be 10 s at 3.5 K [3] and expected to be even longer at 10 mK used
here). We find that the measured spin relaxation rate (1/T1) follows the square of the
cavity-spin coupling constant, as expected. In this way, the Purcell effect provides a
possible mechanism to engineer spin relaxation, thus making mK ESR feasible in
systems which would otherwise possess impractically long relaxation times.
[1] E. M. Purcell, Spontaneous emission probabilities at radio frequencies, Phys. Rev.
1946, 69, 681.
[2] P. Goy, J. M. Raimond, M. Gross, S. Haroche, Observation of Cavity-Enhanced
Single-Atom Spontaneous Emission, Phys. Rev. Lett. 1983, 50, 1903.
[3] G. Wolfowicz et al., Decoherence mechanisms of 209Bi donor electron spins in
iso-topically pure 28Si, Phys. Rev. B, 2012, 86, 245301.
Parallel Sessions
Electrical detection of magnetic resonance: From
broad-band excitation to spin mechanics
M.S. Brandt
Martin S. Brandt, [email protected]
Walter Schotty Institut, Technische Universität München, Germany
Via the Pauli principle, spins influence charge transport processes. This can be used to
very sensitively detect paramagnetic states, to microscopically understand charge
transport and to measure its dynamics. The talk will introduce different approaches to
the electrical detection of magnetic resonance, including real-time measurements and
broad-band excitation, and will discuss some applications to semiconductor physics
such as the crystal fields in silicon monitored by quadrupole interaction of As donors
and the specifics of recombination in photovoltaic materials.
Parallel Sessions
Transient Electrically Detected Magnetic
Resonance Spectroscopy applied to Organic
Solar Cells
F. Kraffert1, R. Steyrleuthner2, C. Meier3, R. Bittl4, J. Behrends5
Felix Kraffert, [email protected]
1-5 Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, Berlin,
Germany
Techniques based on electron paramagnetic resonance spectroscopy can provide
valuable insight into excitation transfer pathways in organic semiconductors used as
absorber layers in solar cells. However, these measurements are usually performed on
"model systems", and the conclusions drawn from such experiments may not be valid
under true solar cell operating conditions.
Here we report on the development of a setup that allows for simultaneous detection
of transient electron paramagnetic resonance as well as transient electrically detected
magnetic resonance (trEDMR) signals from fully-processed and encapsulated solar
cells. Combining both techniques provides a direct link between photoinduced triplet
excitons, charge transfer states and free charge carriers as well as their influence on
the photocurrent generated by organic photovoltaic devices. Our results obtained from
solar cells based on poly(3-hexylthiophene) and a fullerene-based electron acceptor
show that the resonant signals observed in low-temperature (T = 80 K) trEDMR
spectra can be attributed to positive polarons in the polymer as well as negative
polarons in the fullerene phase, indicating that both centers are involved in spindependent processes that directly influence the photocurrent.
Parallel Sessions
Development of New Nitroxide Spin Labels
B. Hajjaj1, S. Bell2, D. Georgiev3, A.N. Hulme4, M. Haugland5, E.A. Anderson6,
J.E. Lovett7
Janet Lovett, [email protected]
1, 2, 7 PHYESTA School of Physics and Astronomy, University of St Andrews, UK
3, 4 EaStCHEM School of Chemistry, University of Edinburgh, UK
5, 6 Chemistry Research Laboratory, University of Oxford, UK
Site-directed spin labelling (SDSL) usually targets cysteine residues with thiol
reactive spin labels. However, this can pose a problem for looking at proteins that
have multiple naturally occurring cysteine amino acids, particularly intracellular
proteins where these cysteines are not part of disulfide bonds. We are developing
methods to site specifically target the labelling of cysteine rich proteins.
The first method is to label an unnatural amino acid which has orthogonal
functionality to natural amino acids.[1] We will present work with the Cu(I) catalyzed
cycloaddition “click” reaction with an alkyne functionalised amino acid incorporated
into myoglobin.
The second method is to label pairs of natural amino acids such cysteines: a
potentially useful ap-proach for both proteins which are cysteine or that contain just
one or two disulfide bonds. We are developing an arsenical label which should only
bind to cysteine pairs and we are utilising next generation maleimides such as bromoor phenoxy-maleimides.[2,3] Our results on labelling proteins and peptides will be
presented and we will compare the flexibility of our new labels to the bis-nitroxide
label Rx.[4]
As well as developing new coupling methods, we are interested in developing
nitroxide spin labels that may be suitable for use in reducing environments such as the
cell and/or at room temperature.[1] These labels have been attached to the sugar of
different nucleic acid bases, using click chemistry, and short DNA oligos synthesised.
We will compare their relaxation times and mobility.
[1] M. J. Schmidt, J. Borbas, M. Drescher, and D. Summerer, JACS, (2014), 136,
1238-1241.
[2] C. Huang, Q. Yin, Q. Zhu, Y. Yang, X. Wang, Z. Qian, and Y. Xu, ACIE, (2011),
50, 7551-7556.
[3] M. E. B. Smith, F. F. Schumacher, C. P. Ryan, L. M. Tedaldi, D. Papaioannou, G.
Waksman, S. Caddick, and J. R. Baker, JACS (2010), 132, 1960-1965.
[4] M. R. Fleissner, M. D. Bridge, E. K. Brooks, D. Cascio. T. Kalai, K. Hideg, and
W. L. Hubbell, PNAS (2011), 108, 16241-16246.
Parallel Sessions
Kinetic Regulation by Transcriptional
Riboswitches
H. Schwalbe1, C. Helmling2, S. Keyhani3, F. Sochor4, H.S. Steinert5, H. Keller6,
M. Hengesbach7, B. Fürtig8
Harald Schwalbe, [email protected]
1-5, 7, 8 Inst. für Org. Chem./Chem. Biol., Zentrum für biomolek. magn. Resonanz
(BMRZ), Goethe-Universität Frankfurt, Frankfurt/M, Germany
6 Inst. für Biowissenschaften, Zentrum für biomolek. magn. Resonanz (BMRZ), GoetheUniversität Frankfurt
Transcriptional riboswitches regulate gene expression by termination of transcription in
response to the presence or absence of a particular metabolite. These type of riboswitches
operate under kinetic control, where ligand binding and transitions between mutually
exclusive conformations are co-transcriptional events.[1] The full length mRNA the
guanine sensing riboswitch from B.subtilis[2,3] and the 2’dG sensing riboswitch from
M.florum[4,5] adopt the terminator conformation at thermodynamic equilibrium regardless
of whether the ligand is present.
We developed a method for simultaneous screening of RNA secondary structure of a
multitude of transcriptional intermediates at single nucleotide resolution. We applied this
approach to monitor the transcriptional progress by screening the secondary structure of 30
different transcriptional intermediates of the 2’dG-sensing riboswitch. Ligand binding by
transcriptional intermediates turned out to be highly dependent on the [Mg2+]. While all
intermediates with a folded aptamer domain bind 2’dG at low [Mg2+], intermediates
adopting the on-state can bind 2’dG and switch to the off-state but require increasing
[Mg2+] with increasing stability of the antiterminator. We further determined segments on
the riboswitch, in which a particular conformation is adopted in both absence and presence
of ligand. In particular, at [Mg2+] = 3 mM, ligand binding can occur over a stretch of 41 nt,
while the kinetically stabilized on-state is stable for a stretch of 22 nt in the absence of
ligand and for a stretch of 16 nt in the presence of ligand.
[1] Wickiser, J. K., Winkler, W. C., Breaker, R. R. & Crothers, D. M. Mol. Cell 18, 49–60
(2005)
[2] Christiansen, L. C., Schou, S., Nygaard, P. & Saxild, H. H. J. Bacteriol. 179, 2540–50
(1997).
[3] Mandal, M. et al. Cell 113, 577–86 (2003).
[4] Kim, J. N., Roth, A. & Breaker, R. R. Proc. Natl. Acad. Sci. U. S. A. 104, 16092–16097
(2007).
[5] Wacker, A. et al. Nucleic Acids Res. 39, 6802–12 (2011).
Parallel Sessions
Enhancing DEER distance distribution
measurements by optimized passage pulses
G. Jeschke1, S. Pribitzer2, N. Wili3, A. Dounas4, J. Soetbeer5, Y. Polyhach6, M. Qi7,
A. Godt8, A. Doll9
Gunnar Jeschke, [email protected]
1-6, 9 Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland
7, 8 Faculty of Chemistry and Center for Molecular Materials, Bielefeld University,
Unversitätsstraße 25, 33615 Bielefeld, Germany
An optimum DEER measurement between labels of the same type uses a fraction λ of
the spin transitions as pumped transitions and a fraction 1-λ as observer transitions and
does not influence any transitions by both the observer and pump pulses. Distance
measurements between Gd(III) labels are very far from this ideal, which can be better
approached by making use of shaped frequency-modulated pulses. Ultrawideband prepolarization pulses shift polarization from otherwise unused satellite transitions of the
S = 7/2 spin to the observed central transition (CT) [1]. For enhancing modulation
depth, λ echo suppression effects must be taken into account that arise from excitation
of satellite transitions that share a level with the CT. By adding a second pump pulse
on the other side of the CT, λ can be almost doubled without significant further echo
suppression and with the additional advantage of compensating Bloch-Siegert phase
shifts.
In measurements between nitroxide labels the distance range is limited by protoninduced transverse relaxation. The five-pulse DEER experiment [2] reduces such
relaxation by dynamical decoupling. However, non-ideal band selectivity of the pump
pulses introduces artifacts that require more elaborate and less robust data analysis,
which limits the number of refocusing cycles and thus decoupling efficiency.
Optimized passage pulses reduce artefact peaks in distance distributions obtained by
Tikhonov regularization to a level not exceeding the one of noise peaks for typical
biosamples.
[1] A. Doll, M. A. Qi, S. Pribitzer, N. Wili, M. Yulikov, A. Godt, and G. Jeschke,
Phys. Chem. Chem. Phys. (2015) 17(11), 7334-7344.
[2] P. P. Borbat, E. R. Georgieva, J. H. Freed, J. Phys. Chem. Lett. (2012), 4(1), 170175.
Parallel Sessions
Solid State NMR, Quantum Mechanical and
Molecular Dynamics Simulations Deliver Spatial
Information about the Organic/Inorganic Interface
in Biohybrids
S.I. Brückner1, S. Donets2, M. Abacilar3, R. Kiyandokht4, A. Jantschke5, A. Dianat6,
R. Gutiérrez7, G. Cuniberti8, A. Geyer9, E. Brunner10
Stephan I. Brückner, [email protected]
1, 5, 10 Institute for Bioanalytical Chemistry, Faculty of Chemistry and Food Chemistry,
TU Dresden, Dresden, Germany
2, 4, 6-8 Institute for Materials Science, Faculty of mechanical science and engineering, TU
Dresden, Dresden, Germany
3, 9 Faculty of Chemistry, Philipps-University Marburg, Marburg, Germany
Interactions between silica and organic molecules are important in various fields.
Especially diatoms are known for their formation of well-defined silicified cell walls and
its associated biomolecules [1]. Solid state NMR is capable of providing information about
the composition and spatial arrangement of the (bio-)silica associated molecules at the
interface between the organic phase and silica. It also allows to derive models for the
predominant interaction mechanisms between the molecules during and after the formation
of biosilica.
In our studies, isotopically labeled choline and polyamines (13C, 15N) are used to study the
interaction with 29Si-labeled monosilicic acid. The formed nanocomposites were analyzed
with respect to interactions between the organic molecules and silica.
The application of CP MAS-based experiments like 1H-13C-{29Si}REDOR [2] and 1H13 1
C/ H-29Si-HETCOR [3] allows the determination of spatial parameters, especially 29Si13
C internuclear distances and molecular orientations in this system. Thus the type of
interaction (hydrogen bonding or electrostatic interactions) between the organic molecules
and the silica surface can be determined. Furthermore, the different phases resulting from
the silica formation are distinguishable. The derived NMR-parameters are in excellent
agreement with the results of corresponding QM and MM simulations. QM calculations
where made with CP2K which provides density functional theory (DFT) methods as well
as classical pair and many-body potentials.
[1] C. Gröger, K. Lutz, E. Brunner, Prog. Nucl. Mag. Res. Sp. 54 (2009) 54-68
[2] T. Gullion, J. Schaefer, J. Magn. Reson. 81 (1989) 196-200
[3] B.-J. van Rossum, H. Foerster, H.J.M. deGroot, J. Magn. Reson. 124 (2003) 516-519
Parallel Sessions
Slow Reorientational Dynamics in Intrinsically
Disordered Proteins: Effect of Hydrodynamic
Coupling
N. Rezaei-Ghaleh1, G. Parigi2, A. Giachetti3, F. Klama4, F. Munari5, S. Becker6,
M. Blackledge7, C. Griesinger8, C. Luchinat9, M. Zweckstetter10
Nasrollah Rezaei-Ghaleh, [email protected]
1 Dept. Structural Biology in Dementia, German Center for Neurodegenerative
Diseases (DZNE), Göttingen, Germany
2, 3, 9 Dept. Chemistry “Ugo Schiff” & CERM, University of Florence, Italy
4-6, 8, 10 Dept. NMR-based Structural Biology, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
7 CNRS, Protein Dynamics and Flexibility, Institut de Biologie Structurale, France
Proteins containing long intrinsically disordered regions (IDPs) represent a large
fraction of human proteome. Due to their association with pathologic states such as
cancers and neurodegeneration, there is growing interest in high-resolution description
of IDPs as potential druggable targets. Dynamical investigation of IDPs by NMR is
hampered by large amplitude motions at several timescales and the coupling between
them. A similar problem arises in flexible multidomain proteins where interdomain
motions introducing a drastic alteration in protein shape are coupled to the overall
tumbling of protein. Recently, we demonstrated that the effective rotational
correlation time of protein domains in flexible multidomain proteins can be well
reproduced on the basis of hydrodynamic drag-mediated coupling between protein
domains [1]. We extended the application of the above-mentioned approach to IDPs.
Treating IDPs as worm-like chains constituted by rigid segments freely jointed to each
other, it was predicted that friction-mediated coupling between protein segments
induces a motion with a long correlation time in dependence of the protein size. The
general presence of such slow motions was supported by proton relaxation dispersion
data at low fields for a series of synuclein variants [2]. Taken the success of our
ensemble-based hydrodynamic approach to quantitatively capture the slow motion in
IDPs, we hope to advance the analysis of NMR relaxation rates in IDPs in order to
better quantify their fast backbone motions.
[1] Rezaei-Ghaleh N, Klama F, Munari F, Zweckstetter M. Angew Chem Int Ed Engl.
2013; 52: 11410-4.
[2] Parigi G, Rezaei-Ghaleh N, Giachetti A, Becker S, Fernandez C, Blackledge M,
Griesinger C, Zweckstetter M, Luchinat C. J Am Chem Soc. 2014; 136: 16201-9.
Parallel Sessions
LC-NMR as a powerful tool for the
characterization of polymers
W. Hiller1, M. Hehn2
Wolf Hiller, [email protected]
1, 2 Faculty of Chemistry and Chemical Biology, TU Dortmund
New methods of the online coupling of liquid chromatography and NMR for the
characterization of polymers are presented. In particular, the coupling of NMR to size
exclusion chromatography (SEC), liquid adsorption chromatography (LAC), liquid
chromatography at critical conditions (LCCC), field flow fractionation (FFF) as well
as two-dimensional liquid chromatography (2D-LC) will be applied to separate and
analyze homopolymers and block copolymers.
New approaches of SEC-NMR have been developed for the correct determination of
molar mass distributions of copolymers [1,2].
The LCCC-NMR coupling was used to characterize block copolymers, the
microstructure and isotopic composition of polymers [3-6]. Critical conditions allow
for the separation of polymers according to their chemical heterogeneity. LCCC-NMR
is the best tool to provide the true chemical composition and molar masses of block
copolymers [3].
Most challenging applications of LC-NMR are related to separations of
microstructures of polymers. Both LCCC and LAC are coupled to NMR for analyzing
PMMA, PS and PI regarding to their microstructures [4-6].
The power of two-dimensional chromatography for the analysis of polymers will be
demonstrated. The first online coupling of 2D-LC-NMR will be shown. 2D-LCCCSEC-NMR of PEOs is used for these experiments [7].
The first coupling of thermal field flow fractionation and NMR will be demonstrated.
Different homo- and copolymers are studied with FFF-NMR [8]. The method is
particularly useful for the separation and determination of molar masses of large
macromolecules.
[1] Hiller, Hehn, Hofe, Oleschko Anal.Chem. 2010,82,8244
[2] Hehn, Wagner, Hiller Anal.Chem. 2014,86, 490
[3] Hiller et al. Macromolecules 2010,43,4853
[4] Hehn, Sinha, Pasch, Hiller J. Chromatogr. A 2015, 1387, 69
[5] Hiller,Sinha,Hehn,Pasch Macromolecules 2011,44,1311
[6] Hehn, Maiko, Pasch, Hiller Macromolecules 2013, 46, 7678-7686
[7] Hiller,Hehn,Sinha,Raust,Pasch Macromolecules 2012, 45, 7740
[8] Hiller, van Aswegen, Hehn, Pasch Macromolecules 2013, 46, 2544
Parallel Sessions
Combining low-field NMR and rheology to
correlate polymer melt properties at different
length and time scales
M. Wilhelm1, K.-F. Ratzsch2, M.B. Özen3, G. Guthausen4
Manfred Wilhelm, [email protected]
1-4 Institut für Technische Chemie und Polymerchemie ITCP, Karlsruher Institut für
Technologie KIT, Karlsruhe, Germany
High field Rheo-NMR has been an established method for 20 years; however outside
the reach of most rheologists. New developments with permanent Halbach magnets
have shrunk NMR magnets to under 20 cm and a few kilograms [1], making it
possible to integrate such a device into a commercial high end rheometer. NMR
sensitivity at fields below 1 Tesla is unproblematic for relaxation time measurements.
Possible applications for low-field Rheo-NMR include the measurement of
quantitative composition in crystallizing polymers and multiphase systems [2] during
the application of non-linear mechanic deformations, e.g. shear induced
crystallization.
For the first time a Rheo-NMR system using a home-made magnet with 0.7 T was
installed in a Rheometrics/TA ARES rheometer, together with a convective sample
heating reaching 200 °C. This unique combination can simultaneously make a full
rheological shear characterization (G’, G’’, LAOS, I3/1, FT-Rheology [3]) while
monitoring the development of the crystallinity via 1H NMR [4]. This enables a direct
correlation between the changes in the modulus as a function of the degree of
crystallinity. To display the possibilities of this new setup, we show measurements on
shear-induced crystallization of isotactic polypropylene and polyethylene regarding
the development of the mass crystallinity and the mobility of the amorphous phase, as
displayed by NMR relaxometry. The findings are also compared to earlier
measurements with conventional rheometry [5], and to crystallization experiments
conducted in the linear mechanical regime [6].
[1] B. Blümich, F. Casanova, S. Appelt, Chem. Phys. Lett., 2009, 477, 231 - 240.
[2] K. Saalwächter, Prog. Nucl. Magn. Reson. Spectrosc., 2007, 51, 1-35.
[3] M. Wilhelm, Macromol. Mater. Eng., 2002, 287, 83-105.
[4] V. Räntzsch, K.-F. Ratzsch, G. Guthausen, M. Wihelm, Magn. Reson. Chem.,
2015, DOI 10.1002/mrc.4219.
[5] S. Vleeshouwers, H. E. H. Meijer, Rheol. Acta, 1996, 35, 391-399.
[6] A. Maus, C. Hertlein, K. Saalwächter, Macromol. Chem. Phys., 2006, 207, 11501158.
Parallel Sessions
NMR Field-Cycling at Ultra Low Magnetic Fields
B. Kresse1, A.F. Privalov2, M. Hofmann3, E.A. Rößler4, F. Fujara5
Alexei F. Privalov, [email protected]
1, 2, 5 Institut für Festkörperphysik, TU Darmstadt
3, 4 Experimentalphysik II, Universität Bayreuth
A field cycling (FC) NMR experiment is presented which allows for evolution fields
in the sub-microtesla range such that the smallest 1H-resonance frequency of 12 Hz
was measured [1]. Moreover, this technique offers the possibility of a simultaneous
determination of magnetic fields down to a few microtesla and the measurement of the
corresponding T1 in these fields [2]. The technique enables broad band spin-lattice
relaxation dispersion experiments down to about 100 Hz 1H Larmor frequency and
can be fruitfully applied when studying slow polymer dynamics [3].
[1] B. Kresse, A. F. Privalov, F. Fujara, Solid State NMR (2011), 40, 134-137
[2] B. Kresse, A. F. Privalov, A. Herrmann, M. Hofmann, E. A. Rössler, F. Fujara,
Solid State NMR (2014), 59-60, 45-47
[3] B. Kresse, M. Hofmann, A. F. Privalov, N. Fatkullin, F. Fujara, E. A. Rössler,
Macromolecules, DOI: 10.1021/acs.macromol.5b00855
Parallel Sessions
Segmental Mean Square Displacement in
Polymer Melts Revealed by Field-Cycling 1H NMR
Relaxometry and Field Gradient 1H NMR
M. Hofmann1, B. Kresse2, A.F. Privalov3, N. Fatkullin4, F. Fujara5, E.A. Rößler6
Marius Hofmann, [email protected]
1, 6 Experimentalphysik II, Universität Bayreuth
2, 3, 5 Institut für Festkörperphysik, TU Darmstadt
4 Institute of Physics, Kazan Federal University, Kaza, Russia
Employing a commercial FC relaxometer and a self built one equipped with earth and
stray field compensation, proton larmor frequencies down to 200 Hz are achieved
allowing to probe very slow chain dynamics in polymer melts. The 1H relaxation rate
dispersion is composed of an intra- and an intermolecular contribution,
R1=R1intra+R1inter, the latter being related to the segmental mean square displacement
< r2(t) > via Fourier transformation. It can be isolated, e.g., in isotope dilution
experiments. Assuming frequency-temperature superposition, master curves are
constructed from dispersion measurements carried out at different temperatures which
not only extend the frequency window covered by FC NMR but also enable to
complement the data with corresponding results from FG NMR, a well-established
and absolute method for measuring the diffusion coefficient D. In the entangled state
D becomes time-dependent at sufficiently short times and < r2(t) >=6D(t)t sub-linear.
In the complementary time windows covered by both NMR techniques four powerlaw regimes are observed for high molar masses M, the exponents of which are in
accordance with the tube/reptation model. From our analysis we also extract polymer
specific length and time scales which are compared with mechanical data. We will
show that combining FC and FG NMR is a powerful approach of molecular rheology
[1].
[1] B. Kresse, M. Hofmann, A. F. Privalov, N. Fatkullin, F. Fujara, E. A. Rössler
Macromolecules 2015, 10.1021/acs.macromol.5b00855
Parallel Sessions
Applications of EPR & ENDOR spectroscopy for
the characterisation of paramagnetic
homogeneous catalysts.
D.M. Murphy1, E. Carter2
Damien M. Murphy, [email protected]
1, 2 School of Chemistry, Cardiff University, Cardiff, UK
Both homogeneous and heterogeneous catalysts are extremely important in the
modern chemical industry, since it is estimated that ca. 90% of all processed
chemicals have, at some point in this production, involved the use of a catalyst.
Improvements in catalysts design, function and stability are constantly required, so
that understanding the operational mode and mechanism of the reaction is essential in
order to enhance the performance. Numerous spectroscopic techniques are therefore
used to characterise the active catalysts and interrogate the reaction mechanism. In
systems involving paramagnetic centres, including transition-metal complexes and
coordinated radicals, EPR and the related hyperfine techniques such as ENDOR, are
without doubt the techniques of choice to fully interrogate the system [1]. In this
presentation, results will be presented to demonstrate the utility of 1H ENDOR
spectroscopy to investigate the weak outer sphere non-covalent interactions
contributing to the selectivity of homogeneous catalysts, whilst cw EPR is applied to
investigate the spin state transitions [3] and the transient free radicals [4] that
participate in a range of homogeneous and heterogeneous oxidation reactions.
[1] E. Carter, D.M. Murphy, Electron Paramagnetic Resonance, Vol. 24, Eds. B.C.
Gilbert, V. Chechik, D.M. Murphy, RSC, Cambridge, (2015) 148.
[2] M.E. Owen, E. Carter, G.J. Hutchings, B.D. Ward, D.M. Murphy. Dalton Trans.,
(2012) 41, 11085.
[3] E. Vinck, E. Carter, D.M. Murphy, S. Van Doorslaer. Inorg. Chem., (2012), 51,
8014.
[4] M. Sankar, E. Nowicka, E. Carter, D. M. Murphy, D.W. Knight, D. Bethell, G.J.
Hutchings. Nature Communications, (2014), 5, 3332.
Parallel Sessions
The structure of glasses and its evolution above
Tg – crystallisation, phase separation and species
exchange: lessons from in situ MAS-NMR.
L. van Wüllen
Leo van Wüllen, [email protected]
Institute of Physics, University of Augsburg, Germany
Despite considerable progress in the characterization of the structure of amorphous
solids at ambient temperatures, only sparse information is available about the structure
of the corresponding melts and the evolution of the structure with temperature.
Changes in the atomic structure occurring during cooling of the glass melt contribute
to the configurational entropy of the liquid and are thus closely linked to structural
relaxation and viscous flow. Since the structure of the glass and hence its physical and
chemical properties critically depend on these structural changes and the
corresponding kinetics (e. g. phase separation, crystallisation), a detailed knowledge
of the equilibria between different structural units and their temperature dependence
constitutes a necessary ingredient to a full understanding of the glass structure at
ambient conditions.
Here we present an in-depth study of the network structure of different phosphate
based (aluminophosphates, phosphosilicates) and borosilicate glasses and its evolution
at temperatures above the glass transition temperatures. Employing a range of
advanced solid state NMR methodologies including 31P{27Al}- and 31P{29Si}CPMAS-HETCOR-NMR, 31P{27Al}-REAPDOR-NMR and 29Si{31P}- and 31P{29Si}REDOR-NMR spectroscopy, the structural motifs on short and intermediate length
scales are identified. The evolution at high temperatures is evaluated employing in situ
MAS NMR techniques, allowing to monitor local structural changes, crystallization
and species exchange.
Parallel Sessions
Solid-State NMR Characterisation of 17O- and
29
Si-Enriched UTL-Derived Zeolites
G.P.M. Bignami1, D.M. Dawson2, V.R. Seymour3, P.S. Wheatley4, R.E. Morris5,
S.E. Ashbrook6
Giulia P.M. Bignami, [email protected] *
1-6 School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University
of St Andrews, St Andrews, UK
The vast success of zeolites has brought the elusive goal of targeting new framework
types to the forefront of research. The ADOR (assembly-disassembly-organisationreassembly) method [1] represents a feasible approach to be followed to achieve such
a goal, transforming the way new, stable and active materials can be synthesised. In
this contribution, we report the ADOR synthesis of 17O- and 29Si-enriched UTLderived zeolitic frameworks and their subsequent characterisation through 17O and 29Si
solid-state NMR.
Exploiting the different stages of the ADOR process, the final products have been
successfully 17O- and 29Si-enriched. Specifically, either a natural abundance Ge-UTL
or a 29Si-enriched Ge-UTL has been synthesised, used as the parent zeolite and then
disassembled employing 41% 17O-enriched H217O in a low-volume HCl-catalysed
hydrolysis reaction.
17
O NMR was able to demonstrate the success of this enrichment process and it has
also been possible to selectively enhance the signal from Si-OH interlayer species in
cross-polarised 1D spectra. Moreover, to resolve the intrinsically broad 17O spectral
lineshapes, MQMAS and 17O-29Si correlation experiments were carried out.
Furthermore, 29Si NMR spectra have been usefully employed to track structural
changes in silicon sites depending on hydrolysis conditions.
In conclusion, we show how 17O and 29Si NMR-based structural investigation proves
extremely helpful to gain insights into the ADOR mechanism, shedding light on the
way new and targeted zeolitic structures could be achieved.
[1] Roth et al., Nat. Chem. (2013), 5, 628
* Royal Society of Chemistry NMR DG Postgraduate Meeting Prize Winner.
Parallel Sessions
Amyloid proteins studied by solid state NMR
spectroscopy at high sensitivity
C. Beumer1, L. Gremer2, W. Hoyer3, A. König4, H. Müller5, T. Piechatzek6,
D. Schölzel7, B. Uluca8, F. Weirich9, H. Heise10
Henrike Heise, [email protected]
1-10 Research Centre Jülich, Institute of Complex Systems 6 / Heinrich-HeineUniversität Düsseldorf
Protein misfolding and amyloid formation are connected to a variety of diseases, like
the neurodegenerative disorders Alzheimer’s disease, Parkinson’s disease and
sponigiform encephalopaties or other disease associated amyloidosis [1]. Here, we
present results obtained on the 37-residue peptide hormone IAPP. Site-specific
resonance assignments could be obtained for all residues. The secondary structure is
in rough agreement with previous findings [2-4], although some differences to
previous results can be seen. Measurements with DNP enhancement at 395 GHz
microwave frequency show consistent results. In total an enhancement factor of 20 is
gained.
The ovine prion protein in its infectious form, PrPSc, is the causative agent of the fatal
disease scrapie in sheep. We report preliminary site-specific resonance assignments
for fibrils obtained by seeding with brain-derived fibrils [6] and compare results from
different seeding protocols. Our data indicate a semi-flexibile N-terminus and a
distinct β-sheet core C terminal of residue -155.7.
[1] Hoyer, W.; Heise, H. In Amyloid Fibrils and Prefibrillar Aggregates; Otzen, D.,
Ed.; Wiley-VCH Verlag GmbH & Co. KGaA: 2013, p 39.
[2] Luca, S.; Yau, W. M.; Leapman, R.; Tycko, R. Biochemistry 2007, 46, 13505.
[3] Alexandrescu, A. T. Plos One 2013, 8, 8.
[4] Bedrood, S.; Li, Y.; Isas, J. M.; Hegde, B. G.; Baxa, U.; Haworth, I. S.; Langen, R.
J. Biol. Chem. 2012, 287, 5235.
[6] Müller, H.; Brener, O.; Andreoletti, O.; Piechatzek, T.; Willbold, D.; Legname, G.;
Heise, H. Prion 2014, 8, 344.
Parallel Sessions
High pressure NMR spectroscopy and mapping of
Xenon binding sites indicate structural fluctuations
in human prion protein
W. Kremer1, D.G. Nair2, D. Schaal3, M.B. Aguiar4, S. Wenzel5, S. Schwarzinger6,
S.P. Narayanan7, H.R. Kalbitzer8
Werner Kremer, [email protected]
1, 2, 4, 7, 8 Institute of Biophysics and Physical Biochemistry and Centre of Magnetic
Resonance in Chemistry and Biomedicine (CMRCB), University of Regensburg
3, 5, 6 Institute of Biopolymers, NW1/BGI, University of Bayreuth
Prion diseases cause fatal neurodegenerative disorders termed transmissible
spongiform encephalopathies (TSEs) that are associated with the accumulation of
fibrils of misfolded prion protein PrP. High pressure is a powerful tool to study the
physicochemical properties of proteins as well as the dynamics and structure of
folding intermediates. In addition the noble gas xenon can been used to identify
hydrophobic cavities in isotope enriched human PrP(23-230) by solution NMR
spectroscopy. We will discuss our findings for the human prion protein in this talk.
Parallel Sessions
(De)coupling of rotational and translational
diffusion in crowded protein solutions
M. Roos1, M. Hofmann2, S. Link3, A. Krushelnitsky4, J. Balbach5, E.A. Rößler6,
K. Saalwächter7
Matthias Roos, [email protected]
1, 3-5, 7 Martin-Luther-University Halle-Wittenberg, Germany
2, 6 University of Bayreuth, Germany
6 University of Bayreuth, Germany
Inside cells, the mean distance between neighboring proteins is similar to their size
[1,2], and therefore Brownian motion gets significantly changed compared to dilute
solutions. By incorporating viscosity measurements, pulsed-field gradient NMR and
1
H NMR relaxometry, i.e., T1 field-cycling NMR measurements along with T1rho and
T2 measurements, we obtain a comprehensive picture on the translational and
rotational motion of proteins over a wide concentration range. We investigated three
proteins (lysozyme, BSA, aB-crystallin [3]) of different size and properties, and
observed for all three of them a slow-down of translational diffusion that
quantitatively follows the increase in macro-viscosity when increasing the protein
concentration. To the contrary, rotational diffusion is rather protein specific and
decouples from translational diffusion to various extents: whereas lysozyme
experiences a rotational correlation time that fully matches the expectation from
translational diffusion and viscosity, rotational diffusion of aB-crystallin occurs
almost independently of concentration, and BSA shows intermediate behavior. We
attribute this effect to protein-specific anisotropic steric and electrostatic interactions,
and link our observations to concepts from colloid science.
[1] R.J. Ellis, Curr Opin Struct Biol (2001), 11, 114–119
[2] R.J. Ellis and A.P. Minton, Nature (2003) 425: 27-28
[3] M. Roos, S. Link, J. Balbach, A. Krushelnitsky, and K. Saalwächter, Biophys. J.
(2015), 108, 98-106.
Parallel Sessions
Solid-state NMR approaches for the investigation
of "large" proteins
T. Wiegand1, C. Gardiennet2, R. Cadalbert3, A. Bazin2, D. Lacabanne2, B. Kunert2,
L. Terradot4, M. Yulikov3, G. Jeschke5, A. Böckmann6, B.H. Meier7
Thomas Wiegand, [email protected]
1, 3, 5, 7 Laboratorium für Physikalische Chemie, ETH Zürich, Zürich, Switzerland
2, 4, 6 IBCP BMSSI, Lyon, France
The rapidly increasing progress in the field of solid-state NMR spectroscopy presently
allows for the elucidation of the 3D structures of small to medium sized proteins
(<100-150 amino acids) by NMR alone whereas the structure investigation of large
proteins still remains challenging. In this contribution we present strategies for an
NMR-based description of dodecameric DnaB helicase (molecular mass of 12*59
kDa) from Helicobacter pylori consisting of 488 amino acids [1] as an example for a
"large" protein. Potentials and limits of classical diamagnetic NMR strategies for
assignment and secondary structure determination were investigated and an attractive
pathway for studying large proteins by separately investigating the individual domains
is presented. In that vein, microcrystalline samples of the N- and C-terminal domain
of HpDnaB were investigated [2] revealing that many structural features are conserved
in the full-length protein which allows to transfer the assignments and secondary
structure information, although also significant differences were identified yielding to
new insights into the structures of the studied proteins. With a molecular mass of 59
kDa, full length HpDnaB is clearly at the upper limit of what can be done by classical
assignment strategies. Therefore, we currently develop paramagnetic solid-state NMR
approaches [3] on covalently spin-labeled mutants of HpDnaB which will enter the
assignment and structure determination progress. EPR investigations (e.g. for
determining spin-labeling efficiencies quantitatively) complement the performed
studies.
[1] C. Gardiennet, A. K. Schütz, A. Hunkeler, B. Kunert, L. Terradot, A. Böckmann,
B. H. Meier, Angew. Chem. Int. Ed. 2012, 51, 7855-7858.
[2] T. Wiegand, C. Gardiennet, F. Ravotti, A. Bazin, R. Cadalbert, D. Lacabanne, B.
Kunert, P. Güntert, L. Terradot, A. Böckmann, B. H. Meier, Biomol. Assign. 2015,
submitted.
[3] G. Pintacuda, G. Kervern, in Modern NMR Methodology, Vol. 335 (Eds.: H.
Heise, S. Matthews), Springer Berlin Heidelberg, 2013, pp. 157-200.
Parallel Sessions
Combined Application of NOEs and RDCs in the configurational
assignment of secondary metabolites from the brown seaweed
Cystoseira baccata
J. Muñoz1, A. Krupp2, S. Immel3, M. Reggelin4, G. Culioli5, M. Köck6
Matthias Köck, [email protected]
1, 6 Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung,
Bremerhaven, Germany
2-4 Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische
Universität Darmstadt, Darmstadt, Germany
5 Université de Toulon, MAPIEM, La Garde cedex, France
The systematic investigation of the brown seaweed Cystoseira baccata actually
revealed seven new meroditerpenes, the cystochromanes A-G [1]. Cystoseira is one of
the most studied genera of the Sargassaceae family and Cystoseira spp. are known to
produce a wide array of terpenes, such as linear diterpenes or meroditerpenes [2-4].
Even though these compounds have been studied for more than 40 years, it was
recently demonstrated that their structures could still raise interesting issues,
especially concerning their stereochemistry [1,5]. The isolation and structure
elucidation of the meroditerpenes from Cystoseira baccata led to a strong indication
for a revision of the bicyclo[4.3.0]nonane system characteristic for compounds of this
family [1].
A detailed study of the relative and absolute configurations of the new molecules as
well as a model compound (the structurally simplest member of the family) was
carried out. For the determination of the relative configuration, NOE-derived
interproton distances were used as input for floating chirality DG/DDD simulations.
Since the number of NOEs was not sufficient for an unambiguous assignment of the
relative configuration, residual dipolar couplings (RDCs, measured in lyotropic liquid
crystalline phases of chiral polyarylacetylenes [6]) were used to refine the structures.
The absolute configurations of the new compounds were assessed by comparison of
their circular dichroism (CD) spectra to the calculated ones.
[1] Muñoz, J.; Krupp, A.; Immel, S; Reggelin, M.; Culioli, G.; Köck, M., J. Nat. Prod.
2015, submitted.
[2] Blunt, J. W.; Copp, B. R.; Hu, W.-P.; Munro, M. H. G.; Northcote, P. T.; Prinsep,
M. R., Nat. Prod. Rep., 2008, 25, 35-94.
[3] Valls, R.; Piovetti, L., Biochem. Syst. Ecol., 1995, 23, 723-745.
[4] Amico, V., Phytochemistry, 1995, 39, 1257-1279.
[5] Mokrini, R.; Ben Mesaoud, M.; Daoudi, M.; Hellio, C.; Maréchal, J.-P.; El Hattab,
M.; Ortalo-Magné, A.; Piovetti, L.; Culioli, G., J. Nat. Prod., 2008, 71, 1806-1811.
[6] Meyer, N.-C.; Krupp, A.; Schmidts, V.; Thiele, C. M.; Reggelin, M., Angew.
Chem. Int. Ed. 2012, 57, 8334-8338.
Parallel Sessions
Novel Techniques for Small Molecules
B. Luy
Burkhard Luy, [email protected]
Institut für Organische Chemie und Institut für Biologische Grenzflächen 4 Magnetische Resonanz, Karlsruher Institut für Technologie (KIT)
Several novel concepts for the improved acquisition of routine experiments and
structure determination of small molecules with (limited) inherent flexibility using
RDCs and molecular dynamics with orientation constraints (MDOC) will be
introduced.
Experiments include the CLIP-COSY as a fast alternative to conventional COSY
experiments with inphase multiplets and the possibility for homonuclear decoupling.
In addition, specifically tilted HMQC/HMBC-type experiments are introduced that
allow homonuclear decoupling based on projection reconstruction methods and fast
experiments based on the ASAP-HSQC approach are presented.
Parallel Sessions
Solution NMR Analysis of Single Molecule
Magnets
M. Damjanovic1, M. Enders2
Markus Enders, [email protected]
1, 2 Institute for Inorganic Chemistry, Heidelberg University
Single molecule magnets (SMMs) are paramagnetic metal complexes displaying
stable magnetization at low temperature. The first SMMs consisted of clusters with
several magnetic centers, but in the last decade well defined mono and dinuclear
SMMs have been reported. The prerequisite for SMM behaviour is a high spin
quantum number combined with a large magnetic anisotropy. Magnetic
measurements, conducted at low temperatures are usually used for characterization of
SMMs. Solution NMR studies at room temperature have been reported in rare cases
only. However, NMR spectroscopy can provide valuable information for SMM
properties, as the mean paramagnetic susceptibility and its anisotropy can be obtained
easily.
We have studied several Terbium-phthalocyaninato (TbPc2) SMMs by paramagnetic
1
H- and 13C NMR and were able to determine important parameters from the NMR
spectra. These include magnetic anisotropies from Residual Dipolar Couplings (RDC)
due to preferential orientation in the magnetic field.
The ligand-radical containing neutral TbPc2, along with its cationic and anionic
counterparts, was used in a combined NMR and DFT study for a comprehensive
determination of various contributions to the hyperfine shift terms of the 1H and 13C
resonances.
The 49 signals observed in the 1H NMR spectrum of a C2h symmetric slipped tripledecker were assigned with COSY and NOESY spectra and used for determining the
rotation barrier of the phthalocyaninato ligand and the coordination geometry of the
Tb ions.
[1] M. Damjanović, K. Katoh, M. Yamashita, M. Enders, J. Am. Chem. Soc. (2013),
135, 14349-14358.
[2] M. Damjanović, T. Morita, K. Katoh, M. Yamashita, M. Enders, Chemistry Eur. J.
(2015), accepted for publication
Parallel Sessions
Characterization of Unexpected Catalytic
Reaction Intermediates by Classical NMR
Methods and PHIP
M. Leutzsch1, L.M. Wolf2, P. Gupta3, M. Fuchs4, W. Thiel5, C. Farès6, A. Fürstner7
Markus Leutzsch, [email protected]
1, 6 NMR Department, Max-Planck-Institut für Kohlenforschung, Mülheim an der
Ruhr, Germany
2, 3, 5 Department for Theoretical Chemistry, Max-Planck-Institut für
Kohlenforschung
4, 7 Department for Organometallic Chemistry, Max-Planck-Institut für
Kohlenforschung
The detection of intermediates is essential to support mechanistic details of catalytic
reactions, but is complicated by their typically low concentration and short lifetimes.
Nevertheless, the characterization of elusive intermediates has been reported,
including striking recent examples by NMR.[1,2] Recently, Fürstner and coworkers
reported the unusual trans-selective hydrogenation of alkynes catalyzed by [Cp*Ru]
complexes, for which the mechanism is still debated. [3] Inspired by previous
parahydrogen induced polarization (PHIP) studies of a similar reaction by Bargon and
his coworkers[4], we used the same approach to detect key intermediates in the novel
catalytic system. During our investigations, we were able to observe previously
undescribed hyperpolarized NMR signals. Further NMR examination revealed the
structure of these compounds to be carbene intermediates, which was later confirmed
by X-ray. Most interestingly, the PHIP experiments demonstrate that the hydrogen
molecule in these intermediates is transferred to a single carbon atom. The mechanism
of this “gem-hydrogenation” and the role of the yet unprecedented carbene
intermediate in the catalytic cycle was then further investigated by EXSY-NMR and
DFT calculations.[5]
[1] M. B. Schmid, K. Zeitler, R. M. Gschwind, Angew. Chem. Int. Ed. (2010), 49,
4997–5003.
[2] A. Berkessel, S. Elfert, V. R. Yatham, J.-M. Neudörfl, N. E. Schlörer, J. H. Teles,
Angew. Chem. Int. Ed. (2012), 51, 12370–12374.
[3] K. Radkowski, B. Sundararaju, A. Fürstner, Angew. Chem. (2013), 125, 373–378.
[4] D. Schleyer, H. G. Niessen, J. Bargon, New J. Chem. (2001), 25, 423–426.
[5] M. Leutzsch, L. Wolf, P. Gupta, M. Fuchs, C. Farès, W. Thiel, A. Fürstner,
manuscript in preparation
Parallel Sessions
Distance measurements on Spin-labeled TRIM
Proteins
M.A. Stevens1, H. El-Mkami2, D.G. Norman3
David G. Norman, [email protected]
1,3 Nucleic Acid Structure Research Group, College of Life Sciences, University of
Dundee, UK
2 School of Physics and Astronomy, University of St Andrews, St. Andrews, UK
Tripartite motif (TRIM) proteins make up a large family of coiled-coil containing
RING E3 ligases, with many different postulated functions and biological roles.
TRIM25 has been shown to function as part of the innate antiviral response pathway
(1). TRIM25 protein dimerises by forming an interdigitated, antiparallel coiled-coil
(2). The dimerisation domain positions the N-terminal catalytic RING domains at
opposite ends of the protein and the C-terminal substrate-binding domains at the
center.
This dimerisation motif appears to be conserved across all TRIM proteins. The extra
N and C terminal domains allow the TRIM family of proteins to be separated into as
many as 11 subfamilies.
We are investigating the structure of TRIM proteins using spin labeling and pulsed
EPR. We are concentrating on two specific proteins of diverse subgroups (one being
TRIM25 and the other TRIM63). The TRIM anti-parallel coiled-coil is around 170Å
long and requires the measurement of extreme distances which we can access using
total system deuteration. We will present some preliminary measurements on the
coiled-coil domain including distance measurements that exceed anything previously
recorded using EPR.
[1] Mcnab FW, Rajsbaum R, Stoye JP, & O'Garra A (2011) Tripartite-motif proteins
and innate immune regulation. Curr Opin Immunol 23(1):46-56.
[2] Sanchez JG, et al. (2014) The tripartite motif coiled-coil is an elongated
antiparallel hairpin dimer. P Natl Acad Sci USA 111(7):2494-2499.
Parallel Sessions
Pulse EPR Distance Measurements in Dimeric
and Multimeric Systems
S. Valera1, A. Giannoulis2, K. Ackermann3, B.E. Bode4
Bela E. Bode, [email protected]
1-4 EaStCHEM, Biomedical Sciences Research Complex, and Centre for Magnetic
Resonance, University of St Andrews, UK
Distance measurements by pulsed EPR spectroscopy are an emerging complementary
tool for structural biology. The method is particularly appealing for systems which are
intractable via NMR or crystallography. Systems forming homo-dimers or homomultimers pose additional challenges as the introduction of a single spin-labelling site
leads to the presence of two or more radicals in the actual multimer. Especially for
more than two spins this is known to lead to complications in data analysis [1].
Here, we report recent results in monitoring protein dimerisation and a corresponding
biomimentic model [2]. Furthermore, we will update on model studies [3,4] and
applications in homo-multimeric systems.
[1] G. Jeschke, M. Sajid, M. Schulte, A. Godt, Phys. Chem. Chem. Phys. (2009), 11,
6580-6591.
[2] K. Ackermann, A. Giannoulis, D. B. Cordes, A. M. Z. Slawin, B. E. Bode, Chem.
Commun. (2015), 51, 5257-5260.
[3] A. Giannoulis, R. Ward, E. Branigan, J. H. Naismith, B. E. Bode, Mol. Phys.
(2013), 111, 2845-2854.
[4] S. Valera, J. E. Taylor, D. S. B. Daniels, D. M. Dawson, K. S. Athukorala
Arachchige, S. E. Ashbrook, A. M. Z. Slawin, B. E. Bode, J. Org. Chem. (2014), 79,
8313–8323.
Parallel Sessions
Protein function studied by in cell EPR
R. Bittl
Robert Bittl, [email protected]
Institut für Experimentalphysik, Fachbereich Physik, Freie Universität Berlin
Blue-light photoreceptors of the BLUF, LOV and cyrptochrome (CRY) protein
families contain flavin as the photoactive pigment. The flavin moiety, in contrast to
the retinal and tetrapyrrole chromophores in rhodopsin and phytochrome, respectively,
can not photo-isomerize upon excitation and there seems to be no common photoreaction mechanism for the three blue-light photoreceptor families.
The photoactivation mechanism of CRY is still under discussion. We have suggested
flavin reduction from the fully oxidized to the neutral radical form as the dark-to-light
transition based on in cell EPR experiments [1]. This suggestion was challenged by
findings of photochemical inactivity of purified mutant proteins involving amino acid
residues in a tryptophane triade supposed to be essential for electron transfer to the
flavin, while the same mutant proteins are found to be signalling competent in vivo.
We were recently able the resolve this seemingly contradictory findings by a further in
cell EPR study, showing photoreduction of the flavin in the mutant proteins under in
cell conditions [2]. In LOV proteins, so far, the formation of a covalent Cys-flavin
adduct is tought to be essential for the signalling process. Here, again making use of in
cell EPR we will present data showing that LOV domains lacking the reactive Cys
residue still are signalling competent and a flavin radical state seems to be the
substitue for the covalent adduct [3].
[1] J.-P. Bouly, E. Schleicher, M. Dionisio-Sese, F. Vandenbussche, D. Van Der
Straeten, N. Bakrim, S. Meier, A. Batschauer, P. Galland, R. Bittl, M. Ahmad, J. Biol.
Chem. (2007), 282 (13), 9383–9391.
[2] C. Engelhard, X. Wang, D. Robles, J. Moldt, L.-O. Essen, A. Batschauer, R. Bittl,
M. Ahmad, The Plant Cell. (2014), 26 (11), 4519–4513.
[3] E. F. Yee, R. P. Diensthuber, A. T. Vaidya, P. P. Borbat, C. Engelhard, J. H.
Freed, R. Bittl, A. Möglich, B. R. Crane, submitted.
Parallel Sessions
Polynomial scaling at last: quantum mechanical simulation
of protein and ribonucleic acid NMR, and a lot more
Z.T. Welderufael1, D.L. Goodwin1, L.J. Edwards2, S. Imai3, S. Robson3, G. Wagner3, V.
D'Souza4, M. Carravetta5, P.T.F. Williamson6, J.M. Werner6, B. Odell7, T.D.W. Claridge7,
B. Gouilleux8, L. Rouger8, P. Giraudeau8, J.-N. Dumez9, I. Kuprov10
Ilya Kuprov, [email protected]
1, 5, 10 School of Chemistry, University of Southampton, Southampton, UK
2 Wellcome Trust Centre for Neuroimaging, London, UK
3 Harvard Medical School, Harvard University, Boston, Massachusetts
4 Department of Molecular and Cellular Biology, Harvard University, Cambridge,
Massachusetts
6 Centre for Biological Sciences, University of Southampton, Southampton, UK
7 Department of Chemistry, University of Oxford, Oxford, UK
8 University of Nantes, Nantes, France
9 Institute de Chimie des Substances Naturelles, Gif-sur-Yvette, France
This is a progress report on our effort to build a large-scale magnetic resonance simulation
library that would incorporate all forms of magnetic resonance spectroscopy and imaging
under the same roof. The project is based on the recently discovered polynomially scaling
spin dynamics simulation algorithms that make large-scale calculations possible [1,2] – the
computational complexity no longer scales exponentially with the number of spins in the
system. The software library we are building is called Spinach [3].
Recent additions to Spinach include a J-coupling estimation module for ribonucleic acids
that makes quantum mechanical DNA and RNA magnetic resonance simulation possible, a
double rotation module using Fokker-Planck formalism [4], support for overtone NMR
spectroscopy [5], treatment of scalar relaxation and cross-relaxation processes [5],
treatment of spatially distributed spin dynamics, cutting edge optimal control algorithms
[6], better use of parallel processing [7] and GPGPU coprocessor cards.
On a more general level, it appears that the task of building a generic simulation library that
supports spatial dynamics (diffusion, spinning, hydrodynamics, MRI) at the same
conceptual level as spin dynamics is better served by the Fokker-Planck equation than
Liouville - von Neumann equation: it is our intention to dust off the Fokker-Planck
formalism and make it the centre of the forthcoming version 2.0 of Spinach kernel.
This work is supported by EPSRC (EP/F065205/1, EP/H003789/1, EP/J013080/1,
EP/M003019/1, EP/M023664/1).
[1] I. Kuprov, N. Wagner-Rundell, P.J. Hore, J. Magn. Reson. 189 (2007) 241-250.
[2] J.-N. Dumez, M.C. Butler, L. Emsley, J. Chem. Phys. 133 (2010) 224501.
[3] H.J. Hogben et al., J. Magn. Reson. 208 (2011) 179-194.
[4] L.J. Edwards et al., J. Magn. Reson. 235 (2013) 121-129.
[5] I.M. Haies et al., Phys. Chem. Chem. Phys. 17 (2015) 6577-6587.
Parallel Sessions
Dissolution DNP - Theory and Experiments with a
Dedicated Spectrometer
W. Köckenberger
Walter Köckenberger, [email protected]
Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy,
University of Nottingham, UK
Dynamic nuclear polarization (DNP) is a promising strategy for generating a
significantly increased nonthermal spin polarization in nuclear magnetic resonance
(NMR) and its applications that range from medicine diagnostics to material science.
Being a genuine nonequilibrium effect, DNP circumvents the need for strong
magnetic fields. We provide here a formalism that makes it possible to analyse the
polarization dynamics of large systems of interacting nuclear spins distributed around
one or two electrons. We show analytically that the nonequilibrium buildup of
polarization heavily relies on a mechanism which can be interpreted as kinetically
constrained diffusion [1]. Beyond revealing this insight, our approach furthermore
permits numerical studies of ensembles containing thousands of spins that are
typically intractable when formulated in terms of a quantum master equation.
Furthermore, we will present a summary of recent work optimising a unique
experimental set-up, which is based on a dual isocentre magnet (3.4T and 9.4T) that
was designed to perform rapid dissolution DNP experiment [2].
[1] A. Karabanov, D. Wiśniewski, I. Lesanovsky, and W. Köckenberger, (2015),
Phys. Rev. Lett, 115, 020404
[2] J. Leggett, R. Hunter, J. Granwehr, R. Panek, AJ. Perez-Linde, A. Horsewill, J.
McMaster, G. Smith, W. Köckenberger (2010) Phys. Chem. Chem. Phys. 12(22)
5883-5892
Parallel Sessions
Dynamic Nuclear Polarization with Endogenous
Polarizing Agents
B. Corzilius
Björn Corzilius, [email protected]
Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt
Although MAS NMR has become a powerful and indispensable technique in
structural biology as well as materials science, the inherently low sensitivity of the
nuclear spins is still one of the limiting factors in its application: the small thermal
spin polarization often leads to prohibitively long acquisition times. Dynamic nuclear
polarization (DNP) has been introduced as a tool to overcome this problem by
transferring the significantly larger spin polarization of unpaired electrons to the
nuclei of interest during a typical MAS NMR experiment.[1]
The utilization of endogenous radicals in biomolecules has already been demonstrated
for 1H DNP.[2] The introduction of paramagnetic metal complexes as polarizing
agents has opened many possibilities towards DNP using endogenous paramagnetic
sites of biomolecules.[3] Furthermore, these metals are stable under physiological
conditions which makes them potential polarizing agents for in-cell applications.
In this presentation several routes for the labeling of biomolecules with Mn2+ or Gd3+
will be discussed, including direct metal binding and covalent linking with chelating
tags. Several biomolecular systems containing paramagnetic metal ions including
proteins and nucleic acids will be presented. We show EPR and MAS NMR
experiments in order to investigate metal binding, electron spin properties, as well as
electron–nuclear interactions such as paramagnetic relaxation and signal quenching.
Finally we will demonstrate the direct, intramolecular DNP of 13C from endogenous
metal sites in biomolecules.
[1] A. W. Overhauser, Phys. Rev. (1953), 92, 411; L. R. Becerra, G. J. Gerfen, R. J.
Temkin, D. J. Singel, R. G. Griffin, Phys. Rev. Lett. (1993), 71, 3561; R. G. Griffin
and T. F. Prisner, Phys. Chem. Chem. Phys. (2010), 12, 5737.
[2] T. Maly, D. Cui, R. G. Griffin, A.-F. Miller, J. Phys. Chem. B (2012), 116, 7055.
[3] B. Corzilius, A. A. Smith, A. B. Barnes, C. Luchinat, I. Bertini, R. G. Griffin, J.
Am. Chem. Soc. (2011), 133, 5648.
Parallel Sessions
Effective SABRE Labelling of Oligopeptides
T. Ratajczyk1, T. Gutmann2, P. Bernatowicz3, G. Buntkowsky4, J. Frydel5, B.
Fedorczyk6
Tomasz Ratajczyk, [email protected]
1, 3 Institute of Physical Chemistry PAS, Warsaw, Poland
2, 4 Eduard Zintl Institut für Anorganische und Physikalische Chemie, Technische
Universität Darmstadt, Germany
5 Venitur Sp. z o.o., Krakow, Poland
6 Faculty of Chemistry, University of Warsaw, Poland
Nuclear magnetic resonance suffers strongly from inherently low sensitivity which
results from low polarization. This drawback can be overcome by so-called
hyperpolarization techniques. One of these techniques is Signal Amplification by
Reversible Exchange – SABRE, which employs a reversible interaction of the
molecule, an iridium-based catalyst and parahydrogen. Because of this interaction, a
ternary labile complex of parahydrogen, catalyst and the molecule is formed. In such a
complex, high spin polarization is transferred from parahydrogen to the molecule.
Finally, the complex splits up; however, the molecule is hyperpolarized.
SABRE is capable of sensitizing the NMR signal of only a few bio-relevant
molecules. Thus, the design of appropriate SABRE-active molecular systems is of
vital importance. Herein, we propose a new SABRE activation strategy that will
further expand the set of hyperpolarizable molecular systems. In particular, a SABREactive pyridine-based molecular framework is incorporated into simple synthetic
oligopeptides. SABRE-activity of the pyridine-based framework was preserved. The
SABRE hyperpolarization was observed in both methanol and a methanol/water (v:v
1:1) mixture. The enhancement factors were evaluated. In methanol/water the
evaluated enhancement factors are lower than in pure methanol.
This work has been supported by the Polish National Science Centre (NCN) under
Contract No.: SONATA-2011/03/D/ST4/02345.
Parallel Sessions
Kinases, Phosphatases, Phosphomutases and Gproteins
J.P. Waltho
Jonathan P. Waltho, [email protected]
Manchester Institute for Biotechnology, University of Manchester and Krebs Institute,
University of Sheffield, UK
Using a combination of multinuclear NMR spectroscopy, high resolution X-ray
crystallography, synthetic chemistry and computational chemistry we have explored
the conformational behaviour of proteins under a very wide range of conditions.
Recently, we have focussed on enzymes that catalyse the transfer of phosphoryl
groups, where the non-catalysed reactions can be among the slowest known for a
physiological process: phosphate monoesters, for example, have calculated lifetimes
to spontaneous hydrolysis of up to 1012 years. I will use a range of phosphoryl
transfer enzymes to illustrate what contributes to the very high levels of catalysis
achieved by these enzymes. Specifically, we have examined what happens during
domain folding, during assembly of the native enzyme, during substrate binding, and
during transition state binding. The introduction of metal fluoride species to mimic the
ground states and the transition state of the transferring phosphate group has allowed
us to dissect the steps involved in catalysis. In particular, these enzymes illustrate how
the charge distribution in the close vicinity of the transferring phosphate is tightly
controlled by the enzyme, and how the near transition state complex conformation
reacts to modulation of these charges. I will also discuss phosphoryl transfer in the
context of the domain closure required to bring about catalysis.
[1] Cliff, M. J. et al., J. Am. Chem. Soc. 2010, 132, 6507-6516.
[2] Marston, J. P. et al., J. Mol. Biol. 2010, 396, 345-360.
[3] Baxter, N. J. et al., Proc. Nat. Acad. Sci. USA 2010, 107, 4555-4560.
[4] Liu, X. et al., J. Am. Chem. Soc. 2011, 133, 3989-3994.
[5] Griffin, J. L. et al., Proc. Nat. Acad. Sci. USA 2012, 109, 6910-6915.
[6] Jin, Y. et al., Proc. Nat. Acad. Sci. USA 2014, 111, 12384-12389.
Parallel Sessions
NMR spectroscopy at the edge: From Tau to
TSPO
M. Zweckstetter
Markus Zweckstetter, [email protected]
German Center for Neurodegenerative Diseases (DZNE) / Max Planck Institute for
Biophysical Chemistry / University Medical Center, Göttingen, Germany
We are interested in the folding and misfolding of proteins and in particular in the
molecular basis of the interaction of small molecules with proteins involved in
neurodegenerative diseases. Our studies focus on the microtubule-associated protein
Tau and the mitochondrial membrane protein TSPO.
We have studied the binding of PcTS, the phenothiazine methylene blue (MB) and its
N-demethylated derivatives to human Tau protein. Our studies showed that MB and
its metabolites modify the native cysteines of Tau and retain it in a monomeric
disordered state. In contrast, PcTS binds to aromatic residues of Tau and targets the
protein into noncooperatively stabilized oligomers. Our results suggest that
conformational modulation of Tau is a viable strategy for the development of novel
therapeutics.
The 18-kilodalton translocator protein TSPO is found in mitochondrial membranes
and mediates the import of cholesterol and porphyrins into mitochondria. In line with
the role of TSPO in mitochondrial function, TSPO ligands are used for a variety of
diagnostic and therapeutic applications in animals and humans. We determined the 3D
high-resolution structure of mammalian TSPO in complex with its high-affinity ligand
PK11195. Ligand-induced stabilization of the structure of TSPO suggests a molecular
mechanism for the stimulation of cholesterol transport into mitochondria.
[1] Akoury, E.; Pickhardt, M.; Gajda, M.; Biernat, J.; Mandelkow, E.; Zweckstetter,
M., Mechanistic basis of phenothiazine-driven inhibition of Tau aggregation. Angew
Chem Int Ed Engl 2013, 52 (12), 3511-5.
[2] Jaremko, L.; Jaremko, M.; Giller, K.; Becker, S.; Zweckstetter, M., Structure of
the mitochondrial translocator protein in complex with a diagnostic ligand. Science
2014, 343 (6177), 1363-6.
Parallel Sessions
Combining electron paramagnetic resonance
(EPR) and X-ray crystallography to study the
structure and dynamics of MTSSL spin labels in
protein single crystals of T4 lysozyme
P. Consentius1, B. Loll2, U. Gohlke3, T. Risse4
Thomas Risse, [email protected]
1, 4 Institute of Chemistry and Biochemistry, Physical Chemistry, Freie Universität
Berlin, Germany
2 Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry,
Freie Universität Berlin
3 Max-Delbrück Center for Molecular Medicine, Berlin
The line shape of cw electron paramagnetic resonance (EPR) spectra of spin labeled
proteins has been used extensively to analyze to extract structural and dynamic
information such local dynamics, backbone fluctuations and structural rearrangements
of proteins. In this study we use single crystals of MTSSL labeled T4 lysozyme as a
prototype example of an α-helical protein to investigate the structure and dynamics of
the paramagnetic side chain in detail by a combination of X-ray crystallography and
EPR spectroscopy. X-ray diffraction is used to determine the orientation of the unit
cell with respect to the EPR sample tube, which in turn allows to determine the
orientation of the spin labels for every EPR spectrum of an angular dependent series
given that the structure and orientation of the protein in the unit cell is known. To this
end high-resolution crystal structures of spin labeled T4 lysozyme of the respective
variants were taken at 100 K and room temperature.
We will discuss the angular dependent line shape of EPR spectra taken at room
temperature with respect to the orientation of the spin label as deduced from X-ray
crystallography. A reversible temperature induced transformation in the crystal as well
as the implications of the high-resolution structure for the dynamics of the spin label
encoded in the line shape of the cw-EPR spectra will be discussed.
Parallel Sessions
Time-resolved NMR spectroscopy reveals high
cooperativity in the folding and unfolding of the
fluoride riboswitch
H. Keller1, H.S. Steinert2, E. Duchardt-Ferner3, B. Fürtig4, D. Passias5, H. Schwalbe6,
J. Wöhnert7
Heiko Keller, [email protected]
1, 3, 7 Wöhnert Group, Institute for Molecular Biosciences, Goethe University
Frankfurt / SFB 902 / BMRZ
2 Schwalbe Group, Institute for Organic Chemistry and Chemical Biology, Goethe
University Frankfurt / BMRZ
4, 6 Schwalbe Group, Inst. for Organic Chemistry and Chemical Biology, Goethe
University Frankfurt / SFB902 / BMRZ
5 Wöhnert Group, Institute for Molecular Biosciences
Riboswitches are highly structured non-coding RNAs that regulate gene expression by
direct binding of small molecules. Several classes of riboswitches have been identified
that selectively bind different cofactors, amino acids, nucleobases or even ions. One of
the most spectacular examples for the ligand recognition capabilities of riboswitches
is the fluoride sensing riboswitch which is able to discriminate between the fluoride
ion and the other halogenide ions [1].
A recent crystal structure revealed how this riboswitch is able to bind selectively to
fluoride ions [2]. The fluoride ion is directly coordinated by a cage consisting of 3
Mg2+-ions. The Mg2+-ion cage itself is bound by five backbone phosphates brought
together in close spatial proximity by an intricate RNA tertiary structure containing
several pseudoknot-like interactions and non-canonical base pairing. However, how
the RNA folds into this complicated tertiary structure and how the binding pocket is
assembled is not known.
Here, we investigate the ligand induced folding of the fluoride riboswitch as well as
possible unfolding pathways under different conditions. We show with nucleotide
resolution using time-resolved NMR spectroscopy and a fast mixing device that RNA
folding and unfolding for binding and release of the fluoride ion is highly cooperative.
Our investigations contribute to understanding how RNAs fold into intricate threedimensional structures in order to specifically recognize small ligands and thereby
regulate gene expression.
[1] J. L. Baker, N. Sudarsan, Z. Weinberg, A. Roth, R. B. Stockbridge, R. R. Breaker,
Science (2012), 335 (6065), 233-235.
[2] A. Ren, K. R. Rajashankar, D. J. Patel, Nature (2012), 486 (7401), 85-89.
Parallel Sessions
Routine Application of NMR Spectroscopy in
Official Food Control
D.W. Lachenmeier1, T. Kuballa2
Dirk W. Lachenmeier, [email protected]
1, 2 Chemisches und Veterinäruntersuchungsamt Karlsruhe, Karlsruhe, Germany
Nuclear magnetic resonance (NMR) spectroscopy is gaining more and more
importance in mixture analysis with one large application field in food analysis [1]. In
this presentation, we will summarize our experience in the routine application of
NMR spectroscopy in governmental food control.
The first applications have been developed for beverages, which can be measured
without any sample preparation. For example, it has been possible to detect microbial
beer spoilage [2] or to authenticate fruit juices. In wine analysis, NMR is unique in
providing a comprehensive prediction of the grape variety as well as the simultaneous
quantitative determination of 56 compounds from the same spectrum. In the field of
alcohol-free beverages, we have established an automated processing of spectra that
allows to control the legal limits for various compounds including caffeine,
preservatives and sweeteners.
For solid foods, an aqueous or solvent extract has to be prepared for measurement
with liquid probes, while we found the measurement using solid state NMR currently
not feasible for routine control purposes.
Examples for solid foods include the verification of the labelling of Arabica and
Robusta coffee species [3], the determination of rice type (Basmati), or the detection
of pine nut species that may cause taste disturbances [4].
In conclusion, NMR spectroscopy was judged as suitable for the rapid routine analysis
of samples in official food control and the application range will be extended to
further matrices in the future.
[1] D.W. Lachenmeier, E. Humpfer, F. Fang, et al., J. Agric. Food Chem. (2009), 57,
7194-7199.
[2] D.W. Lachenmeier, W. Frank, E. Humpfer, et al., Eur. Food Res. Technol. (2005),
220, 215-221.
[3] Y.B. Monakhova, W. Ruge, T. Kuballa, et al., Food Chem (2015), 182, 178-184.
[4] H. Köbler, Y.B. Monakhova, T. Kuballa, et al., J. Agric. Food Chem. (2011), 59,
6877-6881.
Parallel Sessions
DOSY: Progress and Pitfalls
M. Nilsson
Mathias Nilsson, [email protected]
School of Chemistry, University of Manchester, UK
NMR is a wonderful tool for determining molecular structure, but it works best when
analysing pure compounds. In mixtures it is commonly not straightforward to
determine which signals come from which compound. As many, if not most,
interesting problems present themselves as mixtures, there is a strong need for
experiments that are capable of efficiently analysing these mixtures.
One such tool is Diffusion-Ordered SpectroscopY (DOSY) in which signals from
different compounds are resolved by the diffusion behaviour of the molecular species.
DOSY is often very effective, and when the NMR spectra are resolved diffusion
coefficient differences of less than 1% can be detected. However, there are several
potential pitfalls in setting up DOSY experiments and analysing DOSY data that can
severely compromise the quality of the information obtainable.
A common, but often overlooked source of error is convective flow; fortunately there
are efficient tools available to detect and mitigate the effects of convection. If
component spectra overlap, analysis is much less straightforward, but can be greatly
improved using more advanced (e.g. multivariate) processing. When molecular
species are of very similar size the standard DOSY experiment is ineffective, but here
diffusion behaviour can often be manipulated in our favour by using a co-solvent in a
“Matrix-Assisted DOSY” experiment.
The most recent advances in setting up and analysing DOSY experiments will be
discussed, and solutions to some of the most important challenges will be presented.
[1] I. Swan, M. Reid, P. W. A. Howe, M. A. Connell, M. Nilsson, M. A. Moore and
G. A. Morris, J. Magn. Reson., 2015, 252, 120-129.
[2] J. A. Aguilar, R. W. Adams, M. Nilsson and G. A. Morris, J. Magn. Reson., 2014,
238, 16-19.
[3] A. A. Colbourne, S. Meier, G. A. Morris and M. Nilsson, Chem. Commun., 2013,
49, 10510-10512.
[4] R. Evans, S. Haiber, M. Nilsson and G. A. Morris, Anal. Chem., 2009, 81, 45484550.
Parallel Sessions
Unravelling the Structures in Complex Mixtures:
Isotope-filtered nD NMR Spectroscopy
N.G.A. Bell1, A.A.L. Michalchuk2, J.W.T. Blackburn3, L. Murray4, M.C. Graham5,
D. Uhrín6
Nicholle G.A. Bell, [email protected]
1-4, 6 School of Chemistry, Kings Buildings, University of Edinburgh, UK
5 School of Geosciences, Kings Buildings, University of Edinburgh, UK
One of the major challenges confronting NMR spectroscopy is the elucidation of
structures contained within chromatographically inseperable mixtures. Where standard
nD NMR experiments fail it becomes neccesary to implement a form of
‘spectroscopic separation’ by combining isotope tagging with purposely designed
NMR experiments. Towards this end we present isotope-filtered nD NMR
spectroscopy [1] which uses NMR active tags to obtain information about the parent
molecules and illustrate this methodology on the most complex mixture on Earth Humic Substances (HS). Created by the microbial degradation of plant and animal
matter, HS represent the main organic component of soil. Due to their importance in
global biogeochemical cycles, HS have been studied by high resolution techniques
such as FT-ICR-MS as well as an array of NMR experiments. However, hindered by
the inherent complexity of HS, neither technique has afforded unambiguous structure
identification of individual molecules. With this in mind, we performed a suite of Xfiltered 3D/4D NMR experiments to study the aromatic components of a 13C
methylated HS sample isolated from a Scottish peaty soil [2]. Using our methodology
we were able to, for the first time, characterise the major phenolic moieties in a HS
sample and bring a new understanding of their source and degradation mechanisms
within this peaty landscape. Our approach is applicable to a wide range of mixtures
using an array of tagging strategies. We are currently exploring several different
approaches based on the principles outlined here.
[1] N. G. A. Bell, L. Murray, M. C. Graham, D. Uhrín, Chem. Commun. (2014), 50,
1694-1697.
[2] N. G. A. Bell, A. A. L. Michalchuk, J. W. T. Blackburn, M.C. Graham, D. Uhrín,
Angew. Chem. Int. Ed., (2015) DOI:10.1002/anie.201503321
Parallel Sessions
Improving Signal Separation for Oligomeric
Structures in Pure Shift HSQC Spectra
L. Kaltschnee1, T. Imhof2, K. Pulka-Ziach3, Yu.E. Moskalenko4, W. Bermel5,
C.M. Thiele6
Lukas Kaltschnee, [email protected]
1, 2, 4, 6 Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische
3 Faculty of Chemistry, University of Warsaw, Poland
5 Bruker Biospin GmbH, NMR Application, Rheinstetten, Germany
Repetitive motives in oligomers intrinsically carry a high risk of signal overlap in
NMR spectra when signals are clustering in specific spectral regions due to structural
similarity. Such a situation was identified throughout the structural analysis of a novel
oligourea, built out of one monomer type. Oligoureas belong to a peptidomimetic
class of helical foldamers[1] and they offer new prospects for designing of selfassembled structures[2].
The high potential of broadband homodecoupling methods to reduce signal overlap in
such cases has recently been presented[3,4], though applications providing decoupling
of diastereotopic methylene groups remain scarce[5,6]. Robust approaches giving
clean signals even in the case of strongly coupled signals are required, to avoid
missing out signals of such protons that may have very weak intensities in
homodecoupled spectra.
To improve signal separation for the hexamer oligourea, in particular in the backbone
region, we combined the perfectBIRD HSQC experiment[6] with the RESET
processing approach[3]. The homodecoupling strategy chosen allows the collection of
broadband homodecoupled spectra of high quality over the full 1H and 13C offset
range, even for diastereotopic methylene groups. While homodecoupling artifacts
cannot be avoided by this method, the RESET processing approach of the data can
provide a strong reduction of the artifacts associated with strongly coupled signals.
High quality correlation maps can therefore be obtained with a good signal separation
even for the pivotal backbone signals.
[1] C. Hemmerlin et al., Helv. Chim. Acta (2002), 85 (11), 3692-3711.
[2] L. Fischer, G. Guichard, Org. Biomol. Chem. (2010), 8 (14), 3101–3117.
[3] P. Sakhaii, B. Haase, W. Bermel, J. Magn. Reson. (2009), 199 (2), 192-198.
[4] L. Paudel et al., Angew. Chem. Int. Ed. (2013), 52 (44), 11616-11619.
[5] T. Reinsperger, B. Luy, J. Magn. Reson. (2014), 239, 110-120.
[6] L. Kaltschnee et al., Chem. Commun. (2014), 50 (99), 15702 – 15705.
Parallel Sessions
Ultrahigh resolution 1H-1H coupling measurement
D. Sinnaeve1, M. Foroozandeh2, M. Nilsson3, G.A. Morris4
Davy Sinnaeve, [email protected]
1 School of Chemistry, University of Manchester, UK /Department of Organic and
Macromolecular Chemistry, Ghent University, Belgium
2-4 School of Chemistry, University of Manchester
Homonuclear scalar couplings are a double-edged sword. They deliver a wealth of
structural information, but equally they are detrimental to spectral resolution,
impeding their accurate measurement. One way to disentangle individual couplings
from complex spectra is the SERF experiment, which delivers a 2D J-resolved
spectrum containing only selected couplings.[1] A variant of this experiment, G-SERF,
uses the Zangger-Sterk pulse sequence element to deliver simultaneously all the
individual couplings to one selected resonance.[2] Other recent variants incorporate
band-selective and Zangger-Sterk pure shift acquisition.[3,4] However, all these
methods can break down in crowded spectra, either because of signal overlap or
because chemical shift differences between coupled spins are too small.
Here, we present the PSYCHEDELIC (Pure Shift Yielded by CHirp Excitation to
DELiver Individual Couplings) experiment, derived from the PSYCHE pure shift
method.[5] It delivers simultaneously all individual couplings to a selected proton, with
minimal constraints on spectral overlap and chemical shift difference, with the usual
high sensitivity and spectral purity of PSYCHE.
[1] T. Facke, and S. Berger, J. Magn. Res. Ser. A, (1995), 113(1), 114-116.
[2] N. Giraud, L. Beguin, J. Courtieu, and D. Merlet, Angew. Chem. Int. Ed., (2010),
49(20), 3481-3484.
[3] J. E. H. Pucheta et al., Chem. Commun., (2015), 51(37), 7939-7942.
[4] D. Pitoux, et al., Chem. Eur. J., (2015), 21(25), 9044-9047.
[5] M. Foroozandeh, R. W. Adams, N. J. Meharry, D. Jeannerat, M. Nilsson, and G.
A. Morris, Angew. Chem. Int. Ed., (2014), 53(27), 6990-6992.
Parallel Sessions
The BROCODE of NMR: BROadband
COoperative DEcoupling
T. Reinsperger1, F. Schilling2, S.J. Glaser3, B. Luy4
Tony Reinsperger, [email protected]
1, 4 Institute for Biological Interfaces 4, Karlsruhe Institute of Technology,
Eggenstein-Leopoldshafen, Germany
2, 3 Department of Chemistry, Technische Universität München, Garching, Germany
In heteronuclear correlation spectroscopy, decoupling sequences are a key element in
every experiment where resolution and sensitivity are of higher importance than the
information provided by heteronuclear couplings. Pulse sequences are needed which
provide high signal intensity and low artifact levels for a wide range of resonance
offsets. Up to recently it was best-practice to pursue these goals in three steps:
1) Find a robust inversion pulse
2) Expand this inversion pulse by phase cycling
3) Dynamically alter the timing of the sequence in order to achieve cancellation of
artifacts.
Maybe the best standard implementation addressing artifacts originating from the
three-step approach is adiabatic bilevel decoupling [1]. It relies on adiabatic frequency
sweeps as inversion elements and a temporal variation at the beginning of the
sequence for each of the successive scans of an NMR experiment that ultimately
cancels the most spurious artifacts that are introduced by the repetitive sweeping
scheme.
Recently, methods based on Optimal Control Theory [2] have been introduced that
tackle all of the three above-mentioned tasks simultaneously. By combining the
Optimal Tracking algorithm [3] with multi-scan cooperativity [4], it is possible to
derive a complete set of decoupling sequences that compensate each other’s
imperfections de novo. In this work, we compare the results of the Optimal Control
approach with the adiabatic bilevel technique in cases where the radio frequency
power levels are high enough as well as too low to fulfill the adiabatic condition.
[1] Ē. Kupče, R. Freeman, G. Wider, K. Wüthrich, J. Magn. Reson. A 122, 81 -84
(1996)
[2] N. Khaneja, T. Reiss, C. Kehlet, T. Schulte-Herbrüggen, S.J. Glaser,
J. Magn. Reson. 172, 296-305 (2005)
[3] J.L. Neves, B. Heitmann, N. Khaneja, S.J. Glaser, J. Magn. Reson. 201, 7-17,
(2009)
[4] M. Braun, S.J. Glaser, J. Magn. Reson. 207, 114-123 (2010)
Parallel Sessions
Extended Acquisition Time (EXACT) NMR
I.E. Ndukwe1, C. Cobas2, C.P. Butts3
Ikenna E. Ndukwe, [email protected]
1 Craig Butts Group, School of Chemistry, University of Bristol, Bristol, UK
2 Mestrelab Research, Santiago de Compostela, Spain
3 School of Chemistry, University of Bristol, Bristol, UK
The overall duration of NMR acquisition time (AQ) is a function of the dwell time,
DW and the total number of specified data points, TD (AQ = DW*TD). This defines
the frequency resolution of the spectrum after FT. The duration of acquisition time is,
however, limited by spin relaxation and extensive scalar coupling, further reducing
spectral resolution and sensitivity of 1H NMR spectra. To improve NMR spectral
resolution and sensitivity, multiplets are collapsed into singlets by homonuclear
decoupling either by concatenation of short ‘data chunks’ – PSYCHE [1], or by
interrupted acquisition (‘real-time’ decoupling – HOBS [2,3] and ‘pure-shift’ HSQC
[4]). In the real-time methods, band- or isotope-selective pulses on the target (active)
spins are applied during ‘J-refocussing’ breaks in the acquisition period in order to
refocus coupling. The downside of these methods is that data is not sampled during
the J-refocussing breaks, which artificially shortens the acquisition time – leading to
artificial line broadening.
Herein, we introduce a new method EXACT (EXtended ACquisition Time) which not
only retains the full length of the acquisition time but offers the flexibility of
extending this period as well. Data points (with zero intensity) are acquired during the
J-refocusing period and these points are subsequently reconstructed with the
Mestrenova Iterative Soft Thresholding algorithm to give an FID which reflects the
‘true’ T2* relaxation, maximising resolution and sensitivity and with less than 2 Hz
linewidths achievable in both 1D and 2D EXACT experiments.
[1] Foroozandeh, M.; Adams, R; Meharry, N; Jeannerat, D; Nilsson, M; Morris, G.
Angew. Chem. Int. Ed. (2014), 53, 6990-6992.
[2] Castañar, L.; Saurí, J.; Nolis, P.; Virgili, A.; Parella, T., J. Magn. Res. (2014), 238,
63-69.
[3] Castañar, L.; Nolis, P.; Virgili, A.; Parella, T., Chem. Eur. J. (2013), 19, 1728317286.
[4] Paudel, L.; Adams, R. W.; Király, P.; Aguilar, J.; Foroozandeh, M; Cliff, M;
Nilsson, M; Sándor, P; Waltho, J; Morris, G. Angew. Chem. Int. Ed. (2013), 52,
11616-11619.
Parallel Sessions
Compensation of Pulse Transients in NMR
Spectroscopy: Application to Symmetry-Based
Recoupling in Solid-State NMR
J. Wittmann1, K. Takeda2, B.H. Meier3, M. Ernst4
Johannes Wittmann, [email protected]
1, 3, 4 Physical Chemistry, ETH Zürich, Zürich, Switzerland
2 Division of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
Pulse Transients, e.g. deviations of amplitude and phase of the rf pulse inside the
probe's coil from the desired values programmed at the spectrometer can have a severe
impact on the performance of pulse sequences and cause significant differences
between different experimental setups [1-3]. This is especially the case, if the spininteraction to be exploited in the experiment (e.g. the dipolar interaction) is small
compared to potential competing error terms.
One possibility to generate transient-compensated pulses is an approach based on
linear response theory [4]. However, it is not possible to achieve transient-free
rectangular pulses, but only pulses with edges of finite rising and falling time. In this
presentation we demonstrate how to implement such transient-compensated
amplitude-shaped pulses as basic elements in symmetry-based pulse sequences using
the double-quantum recoupling sequence POST-C721 as an example [5,6].
Based on a Floquet analysis we propose modifications to the basic elements that retain
high recoupling efficiencies combined with optimal error-term compensation.
Properties of the transient-compensated sequences with different modified basic
elements are analyzed using numerical simulations and experimental data.
We demonstrate that the application of transient-compensated pulses, where the rf
field acting on the spins in the coil is controlled by the spectrometer operator, lead to a
high reproducibility of the experiments, especially if small dipolar couplings shall be
measured by symmetry-based recoupling.
[1] M. Mehring, Rev. Sci. Instrum. (1972), 43,649
[2] W.-K. Rhim, et al., J. Chem. Phys. (1973), 59, 3740
[3] W.-K. Rhim, et al., J. Chem. Phys. (1974), 60, 4595
[4] Tabuchi, et al., J. Magn. Reson. (2010), 204, 327
[5] Hohwy et al., J. Chem. Phys. (1998), 108, 2686
[6] M. H. Levitt, J. Chem. Phys. (2008),128, 052205
Parallel Sessions
The role of (de)localized defects for Charge
carrier separation at photoactive interfaces
M. Rohrmüller1, W.G. Schmidt2, E. Rauls3, U. Gerstmann4
Martin Rohrmüller, [email protected]
1-4 Universität Paderborn, Theoretische Physik, Paderborn
To develop novel materials for photovoltaic or photocatalytic application a detailed
atomistic understanding of charge carrier separation and the corresponding
recombination processes is crucial. In this work we show how microscopic modeling
of the involved defect states helps to analyze the data obtained from magneto-optical
experiments. It will also be demonstrated that theory can give valuable information
about the charge carrier separation, which give some hints for further improvement of
the materials, even if this kind of information is not directly accessible by experiment.
This is shown using the interface of amorphous silicon and crystalline silicon (a-Si/cSi) (in solar cells) as a prototype example [1]. As investigated by orientation
dependent electrically detected magnetic resonance (EDMR) and density functional
theory (DFT) we analyze the spin-dependent recombination. By this we find that (i)
the interface exhibits microscopic roughness, (ii) the localized interface defects mimic
the famous Pb-centers at the Si/SiO2 Interface, (iii) we identify the microscopic origin
of the conduction and valence band tail states, whereby (iv) the role of excitonic
coupling to localized electrons is discussed.
[1] A. B. M. George, J. Behrends, A. Schnegg, T. F. Schulze, M. Fehr, L. Korte,
B.Rech, K. Lips, M. Rohrmüller, E. Rauls, W. G. Schmidt, and U. Gerstmann, Phys.
Rev. Lett. (2013), 110, 136803.
Parallel Sessions
Spin decoherence at high magnetic fields
S. Takahashi
Susumu Takahashi, [email protected]
Department of Chemistry and Department of Physics, University of Southern
California, Los Angeles CA, USA
Electron paramagnetic resonance (EPR) spectroscopy interrogates unpaired electron
spins in solids and liquids to reveal local structure and dynamics, for example, EPR
can probe the origin of decoherence in condensed matter, which is of fundamental
importance to the development of quantum information processors. The spectral
resolution, spin polarization, sensitivity, and time resolution of pulsed EPR all
increase with increasing static magnetic field and the associated Larmor precession
frequency. In this presentation, I will present development of a high-field pulsed EPR
spectrometer [1,2] and novel applications of pulsed EPR spectroscopy at high
magnetic field that enables the control of spin decoherence due to the electron spin's
local environment. In particular, I will discuss our demonstration of quenching spin
decoherence of diamond [3] and identification of decoherence mechanisms in
molecular magnets [4,5].
[1] F. Cho et al., Rev. Sci. Instrum. 85 , 075110 (2014).
[2] V. Stepanov et al., Appl. Phys. Lett. 106, 063111 (2015).
[3] S. Takahashi et al., Phys. Rev. Lett. 101, 047601 (2008).
[4] S. Takahashi et al., Nature 476, 76 (2011).
[5] C. Abeywardana et al., in-preparation (2015).
Parallel Sessions
CMOS oscillator based frequency and amplitude
sensitive electron spin detection
J. Anders
Jens Anders, [email protected]
Institute of Microelectronics, University of Ulm, Ulm, Germany
Despite its inferior sensitivity, inductive detection of the EPR effect is still the most
widely used detection method because it can work at ambient conditions, requires no
special sample properties, is compatible with all biological samples and therefore
represents the by far most versatile EPR detection principle. The relatively poor spin
sensitivity of inductive EPR detection originates in the relatively small number of
polarized spins at room temperature. As a result, using inductive EPR detection, the
amount of required sample material is relatively large, presenting a significant
obstacle to the analysis of mass limited samples as it is e.g. the case for biological
samples which are often associated with multi-stage syntheses, combinatorial
chemistry procedures and natural product extracts. In this talk, it will be explained
how modern CMOS integrated circuit technologies can be used to manufacture
oscillator-based, miniaturized, high-resolution inductive EPR detectors for both
frequency and amplitude sensitive cw-EPR experiments, which allow for a
simultaneous measurement of the real and the imaginary part of the complex sample
susceptibility. Furthermore, thanks to the scaled down transistors available in modern
nanometer CMOS technologies the oscillator based detectors can be realized for
elevated operating frequencies between 10 and 300 GHz, thereby benefiting from the
enhanced spin polarization at the corresponding elevated B0 fields. Measured data of
prototypes at 14 GHz, 28 GHz [1] and 56 GHz will validate the proposed method.
[1] J. ANDERS, K. ANGERHOFER, G. BOERO: K-band single-chip electron spin
resonance detector. In: Journal of Magnetic Resonance 217 (2012), S. 19-26.
Parallel Sessions
FD-FT THz-EPR for Zero-Field Splittings of 1000
GHZ and Above
J. Nehrkorn1, S. Stoll2, K. Holldack3, A. Schnegg4
Joscha Nehrkorn, [email protected]
1, 4 Institut für Nanospektroskopie, Helmholtz-Zentrum Berlin für Materialien und
Energie
2 Department of Chemistry, University of Washington
3 Institut für Methoden und Instrumentierung der Forschung mit
Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie
Very large zero field splittings (ZFS) of high spin transition metal ion clusters recently
received significant attention due to their importance in single-molecule magnets and
as sensitive probes of the electronic structure. However, direct determination of ZFS
in the THz range is still a challenge. To further push this restriction we developed a
Frequency-Domain Fourier-Transform THz-EPR set-up. This system employs
coherent synchrotron radiation in combination with high magnetic fields (+10T/-10T).
It allows for the determination of ZFS in the range from 100 GHz up to 5 THz [1].
The information extractable from this spectrometer may be even increased by varying
the excitation geometry. Based on recent upgrades we are now able to extract THzEPR spectra in Voigt and Faraday configurations, as well as in transmission and
induction mode and with variable alignment of the linearly polarized THz radiation
with respect to the external magnetic field.
In addition to appropriate spectroscopic tools, precise determination of spin coupling
parameters requires robust simulation routines. To provide such a tool for frequency
and field domain EPR, we developed general, representation-independent formulas
which cover all possible excitation geometries, in particular, linear, circular and
unpolarized microwave excitations.[2] These new capabilities are now included in
EasySpin 5.0.[3] Herein, we present new FD-FT THz EPR results alongside with
spectral simulations.
[1] A. Schnegg, J. Behrends, K. Lips, R. Bittl, and K. Holldack Phys. Chem. Chem.
Phys. (2009), 11, 6820
[2] J. Nehrkorn, A. Schnegg, K. Holldack, and S. Stoll Phys. Rev. Lett. (2015), 114,
010801
[3] J. Nehrkorn, J. Telser, K. Holldack, S. Stoll, A. Schnegg, submitted
Parallel Sessions
New Horizons in THz Frequency Domain
Magnetic Resonance
P. Neugebauer1, D. Bloos2, R. Marx3, J. Vaverka4, J. van Slageren5
Dominik Bloos, [email protected]
1-5 Institut für Physikalische Chemie, Universität Stuttgart, 70569 Stuttgart, Germany
Among the multiple experimental methods for the investigation of the electronic
structure of materials and molecules, High Frequency Electron Paramagnetic
Resonance (HFEPR) is an outstanding method, because of its high g-value resolution
and the access to large energy splittings. This leads to the opportunity to investigate a
wide range of systems, from biomolecules, over metal centers to magnetic materials.
However, traditional field domain HFEPR is slow and may cause structural changes in
the sample during the large magnetic sweeps. This is eliminated by performing
Frequency Domain Magnetic Resonance (FDMR) spectroscopy. We set up a novel
combined HFEPR/FDMR spectrometer, which covers a broad frequency range from
85 GHz to 1100 GHz and magnetic fields up to 17 T.
The recent progress in development of the HFEPR/FDMR spectrometer in Stuttgart
with a Fabry-Pérot-Resonator (Q = 1200) for high sensitivity measurements, a single
crystal rotator and a sample holder for air sensitive samples will be presented. We
greatly reduced the noise caused by frequency switching in fast FDMR. As a result,
we were able to speed up the measurement by two orders of magnitude, leading to
measurement times less than 1 s. Finally we were able to eliminate the standing waves
in the system by applying an additional Faraday rotator into the quasi-optics. The
HFEPR setup is also used to measure cyclotron resonances to investigate the
electronic band structure near the band edge of 2D-materials, like graphene.
Parallel Sessions
Single Spin Magnetic Resonance with 60-90 GHz
(E-Band) Microwave Resonators
P. Neumann1, N. Aslam2, M. Pfender3, M. Scheffler4, H. Sumiya5, H. Abe6,
S. Onoda7, T. Oshima8, J. Isoya9, J. Wrachtrup10
Philipp Neumann, [email protected]
1-3, 10 3. Physikalisches Institut, Universität Stuttgart
4 1. Physikalisches Institut, Universität Stuttgart
5 Sumitomo Electric Industries, Ltd.
6-8 Japan Atomic Energy Agency
9 Research Center for Knowledge Communities, University of Tsukuba, Japan
Single electron and nuclear spin magnetic resonance experiments in the context of
quantum information processing and nanoscale metrology can benefit strongly from
high magnetic fields. The product basis of e.g. an electron and a nuclear spin becomes
closer and closer to the eigenenergy basis, which is favorable for quantum information
processing tasks. In addition, when it comes to sensing and distinguishing single
molecules via their nuclear spins, the chemical shift is a handy fingerprint; the latter
gets larger in absolute numbers and therefore better resolvable in higher magnetic
fields. So far single electron spin experiments were performed at magnetic fields up to
1.6 T (e.g. for Si:P). Here, we explore the frequency range up to 90 GHz, respectively
magnetic fields of up to 3T for single spin magnetic resonance via optical spin
readout. To exploit the available low power amplifiers in the corresponding E-band
fullest, we develop suitable microwave resonators. As a test spin system, we employ
the nitrogen-vacancy (NV) center in diamond. We use the electron spin of a single NV
center to detect proximal nuclear spins via ENDOR. To this end, we design suitable
combinations of dynamical decoupling on the electron spin and tailored nuclear spin
manipulation to detect weakly coupled nuclear spins. Finally, we demonstrate the
benefit of higher magnetic fields by showing longer nuclear spin lifetimes than in
previous studies.
Parallel Sessions
103 7.4. Poster Presentations Poster Presentations
104 Biomaterials in solid state NMR
Poster Presentation P1
The 18kDa translocator protein in the lipid bilayer
G. Jaipuria1, K. Giller2, R. Linser3, S. Becker4, M. Zweckstetter5
Garima Jaipuria, [email protected]
1 Max Planck Institute for Biophysical Chemistry / Deutsches Zentrum für
Neurodegenerative Erkrankungen (DZNE), Göttingen, Germany
2-4 Max Planck Institute for Biophysical Chemistry, Göttingen
5 MBIBPC / DZNE, Göttingen / Center for Nanoscale Microscopy and Molecular
Physiology of the Brain, University Medical Center, Göttingen
The 18 kDa translocator protein (TSPO) is mainly found on the outer mitochondrial
membrane of steroid synthesizing cells [1]. TSPO was first described as a peripheral
benzodiazepine receptor, a secondary receptor for diazepam. TSPO was subsequently
suggested to be important for the transport of cholesterol into mitochondria.
Expression of TSPO is strongly up-regulated in areas of brain injury and in
neuroinflammatory conditions including Alzheimer’s and Parkinson’s disease. TSPO
ligands have potential diagnostic and therapeutic applications such as attenuation of
cancer cell proliferation and neuroprotective effects. Recently, we determined the
high-resolution structure of mouse TSPO in complex with its diagnostic ligand
PK11195 [2]. Here, we present the latest developments on the study of the structure of
TSPO in a lipid bilayer.
[1] R. Rupprecht et al., Nat. Rev. Drug. Discov. (2010), 9, 971-988.
[2] L. Jaremko, M. Jaremko, K. Giller, S. Becker, M. Zweckstetter, Science (2014),
343, 1363-1366.
Poster Presentations
The effect of oxidized phospholipids in model
membranes studied by dipolar recoupling NMR
T.M. Ferreira1, R. Sood2, R. Bärenwald3, S. Drescher4, K. Saalwächter5, O.H.S. Ollila6
Tiago Ferreira, [email protected]
1, 3, 5 Institut of Physics - NMR group, Faculty of Natural Sciences II, Martin-Luther
University Halle-Wittenberg, Germany
2, 6 Department of Biomedical Engineering and Computational Science, Aalto
University, Finland
4 Biophysical Pharmacy, Faculty of Natural Sciences I, Martin-Luther University
Halle-Wittenberg, Germany
The presence of reactive oxygen species (ROS) causes oxidation of lipids in the
human body. In the last years, several studies have been published showing evidence
for a high increase of the concentration of peroxidized lipids in tissues under different
pathological conditions e.g. in Parkinson’s disease, multiple sclerosis, kidney damage,
preclampsia, catarats and others [1]. However, the effect of peroxidized lipids on lipid
model membranes is still rather unknown at the molecular level. We present a dipolar
recoupling 1H-13C NMR study of the effect of the peroxidized lipid PazePC on
different model membranes. By combining measurements of 1H-13C dipolar couplings
in multilamellar vesicles with MD simulations of small bilayer patches (128 lipids),
we interpret the molecular orientation and protonation state of PazePC and its effect
on the different non-oxidized lipid bilayer matrices. The striking observation is that
the deprotonation/protonation ratio of the carboxylic acid in the peroxidized chain is
sensitive to the bilayer environment, namely that saturated or unsaturated
environments influence the pKa of the carboxylic acid and therefore the interfacial
charge of the bilayer.
[1] T. T. Reed, Free Radical Biology and Medicine (2011), 51 (7), 1302–1319
Characterization of Protonic Conductor Based on
Cellulose Functionalized with Imidazole Molecules
I. Smolarkiewicz1, T. Gutmann2, L. Zhao3, A. Rachocki4, K. Pogorzelec-Glasser5,
R. Pankiewicz6, P. Ławniczak7, J. Tritt-Goc8, G. Buntkowsky9
Iga Smolarkiewicz, [email protected]
1 Institute of Molecular Physics, Polish Academy of Sciences Poznań /
NanoBioMedical Centre, Adam Mickiewicz University in Poznań, Poland
2, 3, 9 Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische
4, 5 Institute of Molecular Physics, Polish Academy of Sciences, Poznań
6 Faculty of Chemistry, Adam Mickiewicz University in Poznań
7, 8 Institute of Molecular Physics, Polish Academy of Sciences, Poznań
Nowadays, an important field of research is finding novel proton-conducting materials
to use as solid electrolytes in electrochemical devices as fuel cells, batteries, sensors,
etc.The aim of the study was synthesis and characterization of polymeric material
based on microcrystalline cellulose functionalized by imidazole (abbreviation: ImCELL). The combination of selected natural polymers with heterocyclic molecules
containing nitrogen atoms will allow to find new, biodegradable proton-conducting
materials which exhibit high electrical conductivity for application in the temperature
range above 100°C.
To investigate the temperature behavior of the electrical property of the samples, the
electrical impedance spectroscopy (EIS) measurements were performed [1]. Powdered
samples of microcrystalline cellulose functionalized by imidazole molecules were
studied by means of 1H, 13C, 15N solid-state MAS NMR and heteronuclear correlation
experiments (HETCOR) in various temperatures. Additionally, dynamic nuclear
polarization (DNP) NMR experiments were performed for the samples of cellulose,
imidazole and Cell-Im.
The obtained results have shown that in the temperature range above the water boiling
point the sample of Cell-Im exhibits approximately four orders of magnitude higher
electric conductivity (up to about 2 × 10-4 S/m at 160 °C) than that of the pure
microcrystalline cellulose [1]. In order to understand the local structure and molecular
dynamics of the molecules within the composite material, the samples were examined
with the use of selected NMR techniques.
[1] I. Smolarkiewicz, et al., Electrochimica Acta (2015), 155, 38–44.
Effects of solvent concentration and composition
on protein dynamics: 13C MAS NMR studies of
elastin in glycerol–water mixtures
D. Demuth1, M. Vogel2
Dominik Demuth, [email protected]
1, 2 Institut für Festkörperphysik, Technische Universität Darmstadt
We use 13C CP MAS NMR to investigate the dependence of elastin dynamics on the
concentration and composition of the solvent at various temperatures. For elastin in
pure glycerol, line-shape analysis shows that larger-scale fluctuations of the protein
backbone require a minimum glycerol concentration of ~0.6 g/g at ambient
temperature, while smaller-scale fluctuations are activated at lower solvation levels of
~0.2 g/g. Immersing elastin in various glycerol-water mixtures, we observe at room
temperature that the protein mobility is higher for lower glycerol fractions in the
solvent and, thus, lower solvent viscosity. When decreasing the temperature, the
elastin spectra approach the line shape for the rigid protein at 245 K for all studied
samples, indicating that the protein ceases to be mobile on the experimental time scale
of ~10-5 s. Our findings yield evidence for a strong coupling between elastin
fluctuations and solvent dynamics and, hence, such interaction is not restricted to the
case of protein-water mixtures. Spectral resolution of different carbon species reveals
that the protein-solvent couplings can, however, be different for side chain and
backbone units.[1]
[1] D. Demuth, N. Haase, D. Malzacher, M. Vogel, BBA-Proteins Proteomics (2015),
1854 (8), 995-1000
Synthesis and Solid State NMR Characterization
of Noval Peptide/Silica Hybrid Materials
M. Brodrecht1, M. Werner2, H. Breitzke3, A.S. Thankamony4, T. Gutmann5,
G. Buntkowsky6
Martin Brodrecht, [email protected]
1-6 Eduard-Zintl-Institute of Inorganic and Physical Chemistry, Technische
Biological mineralization is one of the most interesting topics for material scientists.
Nature manages to create hybrid materials made of an inorganic matrices and organic
fibers to combine most desired and often reverse properties such as robustness and
flexibility. To copy these properties, the material scientist must understand how the
two materials are linked to each other and how they arrange to give these sorts of
materials and consequently show these properties. Extensive studies have been done
to understand the role of apatite, the collagen structure [1-4] and biomineralization
processes in general [5]. The successful synthesis and solid state NMR
characterization of silica-based organic-inorganic hybrid materials is presented. A
collagen like peptide sequence was synthesized and bound on porous silica materials.
The covalent binding of the peptide’s N-terminus was monitored by 15N CP MAS
Dynamic Nuclear Polarization (DNP). The DNP enhancement allows the probing of
natural abundance 15N nuclei and does not require expensive labeling of peptides.
Finally, the 15N chemical shifts also deliver indications for a certain structural
preference of the peptide within the pores.
109 Biomolecules in solution NMR/EPR
Structural Investigation of 2-Fluoroadeninesubstituted RNA
F. Sochor1, B. Fürtig2, R. Silvers3, C. Richter4, H. Schwalbe5
Florian Sochor, [email protected]
1, 2, 4, 5 Center for Biomolecular Magnetic Resonance, Institute for Organic
Chemistry and Chemical Biology, Goethe University Frankfurt, Frankfurt/M,
Germany
3 Department of Chemistry, Francis Bitter Magnet Laboratory, Massachusetts
Institute of Technology
The size limitations of NMR spectroscopy on RNA molecules are constantly pushed
to higher molecular weights using isotopic labeling and multidimensional heteronuclear correlation experiments. However, the loss of resolution and spectral
crowding can only be compensated partially by these methods. Furthermore, the
signal intensities of the imino proton resonances which serve as reporters on
secondary and tertiary structure interactions are highly temperature and solvent
sensible. Therefore, NMR experiments utilizing these protons require very defined
experiment settings. Fluorine-19 (19F) labeling represents a potential alternative. 19F
has a 100 % natural abundance and a chemical shift dispersion which is 100 fold
higher than that of 1H. It can be incorporated in high yields by in vitro transcription
using 19F-labeled nucleotide triphosphates. Depending on the used label, 19F-RNAs
allow the easy identification of cross-signals in multidimensional experiments as well
as the determination of population ratios in multistable RNAs. We therefore
transcribed a 22 kDa RNA aptamer with 2F-ATP and showed that the secondary
structure and the ligand binding activity were not impaired by the label. We could
furthermore show, that 2F-ATP allows the identification of binding reporter signals in
multidimensional experiments.
Structural investigation of the dG-sensing aptamer
domain of Mesoplasma florum via paramagnetic
NMR-Spectroscopy
K. Schnorr1, C. Helmling2, A. Wacker3, H.R.A. Jonker4, N.S. Qureshi5,
D.B. Gophane6, S.Th. Sigurdsson7, C. Richter8, H. Schwalbe9
Kai Schnorr, [email protected]
1-5, 8, 9 Institute for Organic Chemistry and Chemical Biology, Center for
Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt/M,
Germany
6, 7 University of Iceland, Department of Chemistry, Science Institute, Reykjavik,
Iceland
The object of our research is to determine the structure of the 2’-deoxyguanosine
sensing aptamer (I-A) from Mesoplasma florum by NMR. In order to obtain a highresolution NMR structure, we are combining structural restraints extracted from
torsion angles, short-range distances, NOE restraints, H-Bonds and planarity restraints
with long-range information extracted out of paramagnetic relaxation enhancement
(PRE). The site-directed incorpora-tion of the paramagnetic species was performed
noncovalently via hybridization of a spin-labeled fragment to a helix segment of the
aptamer. In cooperation with the Sigurdsson lab (Reykjavik), we have been able to
measure PREs with spin-labels of different dynamical properties at varying positions
of the stem helix. In particular, the different dynamical prop-erties of the labels as well
as the observed proton (exchanging vs. non-exchanging protons) for the transversal
PRE rates (Γ2) have provided further insight into secondary and tertiary interactions
of the I-A aptamer.
Investigation of G-quadruplex-ligand interactions
using NMR-spectroscopy
J. Wirmer-Bartoschek1, L.E. Bendel2, J. Henker3, E. Meggers4, P. Gratteri5,
H. Schwalbe6
Julia Wirmer-Bartoschek, [email protected]
1, 2, 6 BMRZ, Institut für Organische Chemie und chemische Biologie, Goethe
University Frankfurt, Frankfurt/M, Germany
3, 4 Phillips Universität Marburg, Hans-Meerwein-Str., 35032 Marburg, Germany
5 University of Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Firenze, Italy
G-quadruplex structures are important targets in cancer research. Development of
ligands that bind more specifically to G-quadruplex structures than to double-stranded
DNA and that are able to differentiate between different G-quadruplex conformations
is a challenge in this research. Here, we investigate the mode of binding of new
classes of complex ligands to telomeric DNA in two abundant conformations (hybrid
1 and hybrid 2).
While metal-ion complexes are prominent ligands for proteins, they are not so
common yet in quadruplex research. Following the concept of classical
metallointercallators but replacing potential toxic metals by Si, octaedrically
coordinated Si complexes have been shown to bind to DNA by intercalation. Their
potential as quadruplex ligands is investigated here. We show that they are able to
induce quadruplex formation and different ligands show differential binding to the
two G-quadruplex DNAs investigated here.
Gold(III) complexes have recently been discovered as quadruplex binders. The three
Gold(III) complexes investigated here, bind more specific to G-quadruplexes than to
double-stranded DNA. Using NMR-spectroscopy, specific binding of a complex
called Auoxo6 to the hybrid 2 conformation can be identified. Further structural
characterization will be presented.
Structural Characterization of FGFR-ligand
interaction by NMR spectroscopy
F. Kappert1, S. Sreeramulu2, K. Saxena3, C. Richter4, D. Kudlinzki5, H. Schwalbe6
Franziska Kappert, [email protected]
1, 2, 4 Institut für Organische Chemie und Chemische Biologie, Goethe University
Frankfurt, Frankfurt/M, Germany
3, 5, 6 Institut für Organische Chemie und Chemische Biologie, Frankfurt /German
Cancer Research Center (DKFZ), Heidelberg, Germany
Fibroblast growth factors (FGFs)/Fibroblast growth factor receptors (FGFRs) play an
important role in the signaling network of cell growth and development. Deregulation
of the FGFR/FGF signaling network can lead to various diseases including cancer.
Traditionally, the majority of drugs developed for targeting the extracellular domains
of RTKs have been antibodies. SSR128129E (SSR)[1,2], a compound with potential
anti-cancer properties, represents the first multi-FGFR inhibitor, which acts
allosterically on the extracellular domains. However, the exact structural basis for the
binding of SSR to the D3 domain of FGFR still remains elusive. This is partly due to
the fact that the D3 domain of FGFR1, 2 and 4 exists in a molten globule state, posing
huge challenges for structural studies. A recent study[3] of the single FGFR3cD3
domain showed its amenability to solution NMR studies. However, detailed structural
studies are particularly challenging due to its dynamic nature and low protein
solubility. We have overcome both of these hurdles and using a combination of
different NMR experiments and labeled samples achieved 66% of the backbone
assignment of the FGFR3cD3, setting up the platform for the interaction studies with
SSR. We then used NMR chemical shift perturbation (CSP) that reveal a novel
binding pocket (L259, G295, G335, Y337, T338, S348-L354) of SSR and could
visualize its allosteric interaction with FGF1 on the D3 domain. These structural
insights significantly improve our understanding and help us to design novel and
better small molecule FGFR inhibitors.
[1] C. Herbert, U. Schieborr, K. Saxena, J. Juraszek, F. De Smet, C. Alcouffe, M.
Bianciotto, G. Saladino, D. Sibrac, D. Kudlinzki, et al., Cancer Cell (2013), 23, 489–
501.
[2] F. Bono, F. De Smet, C. Herbert, K. De Bock, M. Georgiadou, P. Fons, M. Tjwa,
C. Alcouffe, A. Ny, M. Bianciotto, et al., Cancer Cell (2013), 23, 477–488.
[3] J. Kalinina, K. Dutta, D. Ilghari, A. Beenken, R. Goetz, A. V Eliseenkova, D.
Cowburn, M. Mohammadi, Structure (2012), 20, 77–88.
Orthogonal spin labeling of proteins using Click
Chemistry for in vitro and in vivo applications
S. Suvorina1, D. Klose2, S. Korneev3, D. Grohmann4, E.A. Lemke5, J. Klare6,
H.-J. Steinhoff7
Svetlana Suvorina, [email protected]
1, 2, 6, 7 Department of Physics, University of Osnabrück
3 Department of Biology & Chemistry, University of Osnabrück, Germany
4 Institute of Physical and Theoretical Chemistry, TU Braunschweig, Germany
5 Structural and Computational Biology Unit, EMBL, Heidelberg, Germany
Site-directed spin labeling (SDSL) EPR spectroscopy is a powerful technique to
investigate biomolecules in vitro. However, this method has some limitations in vivo.
Firstly, standard cysteine-based spin labeling becomes impractical due to the large
number of native cysteines in living cells. Secondly, the widely employed nitroxide
spin labels are quickly reduced by the intracellular environment.
In order to solve these challenges we applied Click Chemistry[1] as an alternative
labeling strategy providing fast and selective coupling of azide and alkyne groups. We
chose eGFP as a model protein for in vitro optimization and modified it with an
unnatural amino acid (UAA) [2] containing the required chemical group. The effective
labeling with new synthesized nitroxides was obtained within short incubation times
using the copper-catalyzed azide-alkyne cycloaddition (CuAAC) [3]. Copper-free
click reactions showed a slower reaction kinetic. DEER spectroscopy of a double
labeled variant proves the applicability of our method.
In spite of the known reduction of nitroxides we detected EPR signals for experiments
carried out in E.coli cytoplasm and cells. Nevertheless, we are currently applying
Gd(III)-DOTA complexes and their derivates to avoid spin reduction. The toxicity and
incorporation into cells of Gd(III)-DOTA spin labels were determined for E.coli
strains.
[1] H. C. Kolb, M. G. Finn, K. B. Sharpless, Angew. Chem. Int. Ed., 2001, 40, 20042021;
[2] J. W. Chin, S. W. Santoro, A. B. Martin, D. S. King, L. Wang, P. G. Schultz, J.
Am. Chem. Soc., 2002, 124, 9026-9027;
[3] V. V. Rostovtsev, L. G. Green, V. V. Fokin, K. B. Sharpless, Angew. Chem. Int.
Ed., 2002, 41, 2596-2599.
Rapid NMR screening of RNA secondary
structure
S. Keyhani1, C. Helmling2, F. Sochor3, B. Fürtig4, M. Hengesbach5, H. Schwalbe6
Sara Keyhani, [email protected]
1-6 Center for Biomolecular Magnetic Resonance (BMRZ), Institut für Organische
Chemie und Chemische Biologie, Goethe University Frankfurt, Frankfurt/M,
Germany
NMR has become a useful method for RNA structure analysis e. g. to elucidate RNA
folding pathways or functional aspects of regulatory RNA elements. The commonly
used approaches for RNA preparation are time-consuming and with low throughput.
Here, we present a high throughput method for rapid and native preparation of RNA
samples providing NMR data that are comparable to commonly used RNA
preparation approaches. We developed this method for the parallel synthesis of RNA
riboswitch constructs. We show the applicability of our method by screening the
aptamer domain of the 2’dG-sensing riboswitch. We produced several transcription
intermediates within two days and monitored the change in ligand affinity with
increasing RNA chain length. Further, we apply our method for an RNA assignment
strategy in consideration of the fact that varying lengths of the RNA can be prepared
rapidly. Each nucleotide of the RNA can be assigned by comparing the NMR spectra
of two constructs that differ in one single nucleotide.
Structural characterization of the rS1-protein and
its mRNA complexes
N.S. Qureshi1, H.R.A. Jonker2, H. Schwalbe3, B. Fürtig4
Nusrat Qureshi, [email protected]
1-4 Center for Biomolecular Magnetic Resonance (BMRZ), Institut für Organische
Chemie und Chemische Biologie, Goethe University Frankfurt, Frankfurt/M,
Germany
As part of the translational machinery the rS1-protein recognizes mRNAs and
facilitates their interaction with the 30S subunit of the ribosome. It contains six
homologues domains that provide the rS1 with two functionally specialized regions,
enabling interactions with proteins and RNAs [1]. Solution NMR structures of
individual domains were solved but there is no structure available regarding the RNA
binding region [2], [3]. We aim to structurally characterize the rS1 RNA binding
region and to investigate its interaction with the translation initiation region (TIR) of
mRNAs using solution NMR. Here, we use the 5´-UTR and TIR of an mRNA,
comprising an adenine dependent riboswitch (ASW) as substrate [4]. In accordance to
Bisaglia et al. [5] we designed five multidomain constructs, by stepwise truncating the
RNA binding region from the N- and C-terminal ends of the protein. Our
electrophoretic mobility shift assays indicate that constructs containing at least the
third and fourth domains are capable of RNA binding. For the shortest construct we
studied the RNA binding by solution NMR. The timescale for this interaction appears
to be within the intermediate to fast exchange time regime. This finding indicates
dynamic interaction between protein and RNA, characterized by relative high koffvalues and does not contradict previous studies [1]. As a mediator of translation
initiation, the rS1-protein has to bind and prepare the mRNA for the interaction with
the ribosome. Subsequently it has to dissociate from the mRNA, to enable the
formation of the translation initiation complex.
[1] Subramanian, A.R. Prog. Nucleic Acids Res. (1983) 28, 101-142.
[2] Salah, P. Bisaglia, M. Aliprandi, P. Uzan, M. Sizun C. Bontems, F. Nucleic Acids
Res. (2009) 37, 5578-5588.
[3] Giraud, P. Crechet, J. B. Uzan, M. Bontems, F. Sizun C. Biomol. NMR Assign.
(2014) 9, 107-111.
[4] Reining, A. Nozinovic, S. Schlepckow, K. Buhr, F. Fürtig, B. Schwalbe, H. Nature
(2013) 499, 355-360.
[5] Bisaglia, M. Laalami, S. Uzan, M. Bontems, F. J. Biol. Chem. (2003) 278, 1526115271.
Photoresponsive formation of an intermolecular
minimal G-Quadruplex motif
J. Thevarpadam1, I. Bessi2, O. Binas3, H.R.A. Jonker4, C. Richter5, H. Schwalbe6,
A. Heckel7
Oliver Binas, [email protected]
1, 7 Heckel group, Institute for Organic Chemistry and Chemical Biology, Goethe
University Frankfurt, Frankfurt/M, Germany
2-6 Schwalbe group, Institute for Organic Chemistry and Chemical Biology, Goethe
University Frankfurt
Intermolecular G-Quadruplex structures can act as building blocks for
nanotechnological applications, ligating guanine-rich DNA strands in hoogsteen-bond
G-tetrads.[1] The incorporation of an Azobenzene moiety into a DNA strand enables
light control of the system, through isomerization of the Azo-group.[2]
Screening different Azobenzene-DNA constructs, GG-Azo-GG could be identified as
promising system, forming one specific G-Quadruplex structure, that unfolds under
UV-irradiation. The construct was therefore structurally investigated, utilizing NMRmethods involving NOE- and through-bond correlation, showing a highly symmetric
two tetrad Quadruplex structure with two lateral loops. An NMR-structure of GGAzo-GG could be derived from NOE data and angular restraints, obtained from
E.COSY and HSQC experiments.
To show the capability of the system, to couple larger DNA, a model system with a 20
nt Duplex attached to GG-Azo-GG was analyzed by 1D-NMR screening.
[1] G. Mayer, L. Kröck, V. Mikat, M. Engeser, and A. Heckel, ChemBioChem (2005),
6, 1966-1970
[2] J. Zhang, J. Wang and H. Tian, Mater. Horiz. (2014), 1 , 169-184
Conformational flexibility of the isoindoline derived
spin labels
N. Erlenbach1, B. Endeward2, D.B. Gophane3, S.Th. Sigurdsson4, T.F. Prisner5
Nicole Erlenbach, [email protected]
1, 2, 5 Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt,
Frankfurt/M, Germany
3, 4 University of Iceland Science Institute, Reykjavik, Iceland
Due to the hyperfine-coupling- and g-Tensor anisotropy in EPR, which is especially at
high field spectrally resolved, there is an orientation dependency in PELDOR for
systems which are not free in motion. In our work we could show that PELDOR
experiments performed at multiple magnetic fields (0.3, 1.2 and 6.4 T) allows the
determination of conformational flexibility of spin label which are covalently attached
to a nucleic acids based on the orientation of the nitroxide ensemble.
Here we analyzed the dynamic of recently presented isoindoline derived spin label,
which are semi-rigid [1] or conformational unambignious [2]. All of them are
incorporated into chosen positions of a 20mer DNA. This allows studying the
dynamic of the spin labels separated to the known dynamic of the DNA with this
sequence. The DNA double helix dynamics was generated according to the breathing
model developed using the rigid spin label Ç [3]. In addition to this conformational
flexibility of the DNA, the local mobility with an overdue motion of the spin label was
taken into account to accomplish good fits to the experimental PELDOR time traces.
[1] D. Gophane and S. Sigurdsson Chem. Commun.(2013), 49, 999-1001
[2] D.Gophane, B. Endeward, T. Prisner, S. Sigurdsson, Chem. Eur. J. (2014), 20,
15913-15919
[3] A. Marko, V. Denysenkov, D. Margraf, P. Cekan, O. Schiemann, S. Sigurdsson, T.
Prisner, J. Am. Chem. Soc. (2011), 133, 13375-13379
A new RNA model system for investigation of
helicases unwinding mechanism via NMR
spectroscopy
H. Zetzsche1, B. Fürtig2
Heidi Zetzsche, [email protected]
1, 2 Center for Biomolecular Magnetic Resonance (BMRZ), Institute for Organic
Chemistry and Chemical Biology, Goethe University Frankfurt, Frankfurt/M,
Germany
Both in eukaryotic and prokaryotic cells unwinding of RNA molecules is exerted by
RNA helicases, enzymes which separate double stranded ribonucleic acids in an ATP
dependent reaction. RhlB, an E.coli RNA helicase from the DEAD-Box family, is part
of the degradosome. As a key component of this mRNA degradation complex RhlB is
responsible for unfolding secondary structure elements in mRNAs before nucleases
PNPase and RNase E can degrade them. So far only little is known about RhlB’s
unwinding mechanism and in particular how the conformation of the individual RNA
strands changes during destabilization.
In this project we designed and synthesized an artificial RNA substrate for RhlB
whose low molecular weight of 21,2 kDa allows analyses of the unwinding
mechanism via NMR spectroscopy. It is composed of two complementary 21 and 46
nucleotide long strands and includes specific mRNA substrate features of RhlB such
as a 5’ overhang and a hairpin loading platform. Via NOESY and HSQC
measurements we could determine the conformation of RNA duplex as well as the
individual strands and the Mg2+ dependency of the annealing process. Real-time
mixing NMR experiments and fluorescence-spectroscopic studies showed a strong
and homogeneous duplex formation. With this new RNA model system set up it will
be possible to see changes in chemical shift or peak intensity of individual nucleotides
upon binding of RhlB to the double stranded region and the loading platform. This
will give insights into the enzyme’s mechanism and can be expanded by the use of
photocaged or non-hydrolysable ATP.
Rotational Dynamics of Proteins at Crowding
Conditions
A. Krushelnitsky1, M. Roos2, M. Hofmann3, E.A. Rößler4, K. Saalwächter5
Alexey Krushelnitsky, [email protected]
1, 2, 5 Martin-Luther-University Halle-Wittenberg, Germany
3, 4 University of Bayreuth, Germany
The overall Brownian dynamics is one of the key factors affecting biological function
of proteins in a living cell. In most cases, structural and dynamic NMR studies of
proteins are conducted on diluted solutions. However, many protein properties may
change significantly upon a transition from diluted to highly concentrated (crowding)
solution, the latter being more important since crowding mimics the in-vivo
conditions. It has been shown that the effect of increased protein concentration on the
protein Brownian tumbling cannot be simply reduced to increased viscosity. Interprotein interactions give rise to the appearance of the slow (~0.1-10 us) component of
the rotational correlation function which reflects the local anisotropy of microsurrounding for each protein [1,2]. Studying the tumbling correlation function in a
wide time scale range using the routine high field T1/T2/NOE experiments is hardly
possible since the microsecond range of correlation times is the "blind zone" for them.
In this contribution we present a detailed systematic study of the rotational correlation
function of two proteins, lysozyme and BSA, at concentrations from 60 to 250 mg/ml
using field-cycling relaxometry of protein protons in D2O solutions [3] complemented
with standard proton T1rho and T2 measurements. The abundant relaxation data
measured in a frequency range of several orders of magnitude enabled obtaining
detailed quantitative information on the concentration dependence of the rotational
protein dynamics which will be thoroughly discussed.
[1] A. Krushelnitsky, Phys. Chem. Chem. Phys. (2006), 8, 2117-2128.
(2015), 108, 98-106.
[3] I. Bertini, Y.K. Gupta, C. Luchinat, G. Parigi, C. Schorb, and H. Schwalbe,
Angew. Chem. Int. Ed. (2005), 44, 2223-2225.
EPR Studies on the Signal Peptidase LspA and the
Symporter BetP: Probing the Influence of Lipids on
Structure and Functionality
E. Jaumann1, B. Endeward2, A. Laguerre3, I. Waclawska4, V. Dötsch5, C. Ziegler6,
T.F. Prisner7
Eva Jaumann, [email protected]
1, 2, 7 Institute of Physical and Theoretical Chemistry and Center for Biomolecular
Magnetic Resonance (BMRZ), Goethe University Frankfurt, Frankfurt/M, Germany
3, 5 Institute of Biophysical Chemistry and Biocenter Campus Riedberg, Goethe
University
4, 6 Department of Structural Biology, Max Planck Institute of Biophysics Frankfurt
We present initial electron paramagnetic resonance (EPR) experiments on two different
membrane proteins: the Signal Peptidase A (LspA) and the Betaine Symporter BetP.
The Lipoprotein LspA plays an important role in the removal of signal peptides from
prolipoproteins. With a molecular weight of only 19 kDa it belongs to the family of small
helical membrane proteins, whose structures are highly dependent on their lipid
environment. It is therefore crucial to characterize the topology of the protein in a nativelike environment, such as nanodiscs. These are soluble fragments of phospholipid bilayers.
We aim to address the open questions of protein tertiary structure, number of protomers
and the role of the inhibitor globomycin by investigating the system using pulsed electron–
electron double resonance (PELDOR).
The trimeric Na+-coupled Betaine Symporter BetP is an osmoregulating membrane protein
which originates from the soil bacterium Corynebacterium glutamicum, allowing it to
counteract hyperosmotic stress.[1] The activation of BetP is linked to the binding of fatty
acyl chains from the lipid bilayer to the protein and protein surrounding.[2] The protomer’s
different states adopted during the transport cycle have been studied by PELDOR. Distinct
differences between active and inactive condition sample preparation were observed.[3] To
study the influence of the lipid composition on the structure and functionality, we aim to
reconstitute BetP in nanodiscs of different lipid compositions and compare PELDOR data
measured on this system with data obtained from BetP in detergent.
[1] B. Poolman, J. J. Spitzer, and J. M. Wood, Biochim. Biophys. Acta - Biomembr.
(2004), 1666, 88–104.
[2] C. Koshy, E. S. Schweikhard, R. M. Gärtner, C. Perez, O. Yildiz, and C. Ziegler,
EMBO J. (2013), 32, 3096–3105.
[3] P. E. Spindler, I. Waclawska, B. Endeward, E. Schleiff, C. Ziegler, and T. F. Prisner,
(2015), work in progress
Synonymous codons direct co-translational folding
towards different protein conformations
F. Buhr1, S. Jha2, M. Thommen3, J. Mittelstaet4, F. Kutz5, H. Schwalbe6,
M.V. Rodnina7, A.A. Komar8
Felicitas Kutz, [email protected]
1, 5, 6 Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry
and Chemical Biology, Goethe University Frankfurt, Frankfurt/M, Germany
2, 8 Center for Gene Regulation in Health and Disease, Cleveland State University,
Cleveland, Ohio, USA
3, 4, 7 Department of Physical Biochemistry, Max Planck Institute for Biophysical
Chemistry, Goettingen, Germany
The genetic code is degenerate, with up to six synonymous codons encoding a given
amino acid in the protein. The occurrence of synonymous codons in open reading
frames (ORFs) of genes is not random, suggesting the existence of evolutionary
constraints on codon choice. It has been suggested that non-random synonymous
codon usage may result in non-uniform translation kinetics, which could affect cotranslational protein folding. Here, we demonstrate that synonymous codon usage
governs the kinetics of translation, co-and post-translational protein folding and the
final protein structure. We show that ribosome-bound nascent chains of the
mammalian eye lens protein, gamma-B crystallin, expressed from two gene variants
with different synonymous codon composition but encoding the same polypeptide,
attain different conformations as indicated by altered in vivo stability, in vitro
fluorescence-based assays and protease resistance. 2D NMR spectroscopic data
suggest that the observed structural differences are associated with different cysteine
oxidation states of the purified protein expressed from the synonymous gene variants.
Synonymous codon usage altered local and global rates of translation and affected the
efficiency of co-translational folding of protein domains as well as the ultimate stable
conformation attained by the protein.
Structural characterization of a complex between
Protein-Tyrosine Phosphatase A (MptpA) and
Protein-Tyrosine Kinase A (PtkA) from
M. tuberculosis by NMR spectroscopy
A. Niesteruk1, H.R.A. Jonker2, C. Richter3, S. Sreeramulu4, T. Stehle5, H. Schwalbe6
Anna Niesteruk, [email protected]
1-6 Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular
Magnetic Resonance (BMRZ), Goethe University Frankfurt am Main, Germany
Protein-tyrosine phosphatases (PTPs) and protein-tyrosine kinases co-regulate cellular
processes. They are frequently exploited to act as key virulence factors for human
diseases. Characterization of the involved proteins and their interactions is of crucial
importance for understanding the pathogen regulation pathways. Mycobacterium
tuberculosis, the causative organism of tuberculosis, secretes a low molecular weight
PTP (LMW-PTP), MptpA, which is required for its survival upon infection of host
macrophages. PtkA, the kinase complementary to MptpA, belongs to the haloacid
dehalogenase (HAD) superfamily [1] and phosphorylates two key tyrosine residues in
MptpA, thereby co-regulating the cellular function [2, 3]. Previously, we reported the
structure of MptpA and the interaction with PtkA by NMR spectroscopy [4]. Here, we
aim to complement this study by determining the three-dimensional structure of PtkA
and the MptpA-PtkA binary complex.
The NMR backbone assignment of the 216 amino acid protein Δ1-75PtkA is essentially
complete to the extent of 86% for the non-proline residues. Secondary chemical shifts
and NMR-based relaxation studies revealed that the protein PtkA possesses an Nterminally located intrinsically unstructured region (IUR, M1-G80). The biological
function of this disordered tail is unknown. Our paramagnetic spin labelling studies,
suggests transient long-range dynamics between IUR and the structured core domain
of the PtkA.
[1] Bach H, Wong D, Av-Gay Y, Biochemical Journal (2009), 420(2), 155-160.
[2] Wong D, Bach H, Sun J, Hmama Z, Av-Gay Y, Proc Natl Acad Sci U S A (2011),
108(48), 19371-19376.
[3] Chao J D, Wong D, Av-Gay Y, J Biol Chem (2014), 289(14), 9463-9472.
[4] Stehle T, Sreeramulu S, Löhr F, Richter C, Saxena K, Jonker HRA, Schwalbe H,
Journal of Biological Chemistry.(2012), 287(41), 34569-34582
Characterization of the Unstructured N-terminal
Region of Protein Tyrosine Kinase A
M.-T. Hutchison1, A. Niesteruk2, T. Stehle3, J. Wirmer-Bartoschek4, H.R.A. Jonker5,
S. Sreeramulu6, R. Silvers7, H. Schwalbe8
Marie-Theres Hutchison, [email protected]
1-6, 8 Institute of Organic Chemistry and Chemical Biology, Goethe University
Frankfurt , Frankfurt/M, Germany
7 Department of Chemistry, Massachusetts Institute of Technology
Protein disorder is prevalent throughout the kingdoms, with a significant number of
pathogenic prokaryotic organisms holding disordered proteins. Mycobacterium
tuberculosis (Mtb), a tuberculosis pathogen, of the phylum Actinomycetes is one such
prokaryote which contains proteins with stretches of disorder. The protein tyrosine
kinase A (PtkA) of Mtb phosphorylates, and thus regulates, Mtb protein tyrosine
phosphatase (PtpA) which is essential for Mtb survival. Here, we show that the Nterminal domain of the PtkA (PtkAM1-L81) is unstructured and characterize this
unstructured domain using NMR spectroscopy.
While the PtkAM1-L81 is unstructured under denaturing conditions, molten globule like
line broadening is observed under native conditions. Chemical shift perturbations
reveal residual α-helical structure between L40 and T52 and from R66 to A72 under
denaturing conditions as well as under native conditions.
Insight into the folding pathway of human
telomeric G-quadruplex by real time NMR
I. Bessi1, H.R.A. Jonker2, C. Richter3, H. Schwalbe4
Irene Bessi, [email protected]
1-4 Institute for Organic Chemistry and Chemical Biology, BMRZ, Goethe University
Non-canonical four-stranded DNA structures called G quadruplex [1] can be formed
in G-rich regions, such as the 3‘-end single-stranded overhang of telomeres.
Human telomeric G-quadruplexes are highly polymorphic and many structural
topologies have been characterized up to now [2-4], however very little is known
about their folding pathway. G-quadruplex-mediated telomerase inhibition is of great
interest as novel anti-cancer therapy and requires a better understanding of the folding
energy landscape of human telomeric quadruplexes.
We studied the K+-induced folding kinetic of the human telomeric sequence
(TTGGG[TTAGGG]3A) [2] using real-time NMR [5]. Analysis of the NMR derived
kinetic traces allowed us to provide atomistic insight into the folding mechanism of
telomeric G quadruplex.
After injection of K+, two distinct folded states were detected: a major conformation
(hybrid-1) and a previously not characterized minor conformation (hybrid-2), which is
formed faster than the more stable hybrid-1. Interestingly, a partially unfolded state
was also populated during the folding. We propose that the thermodynamic (hybrid 1)
and kinetic (hybrid-2) conformations equilibrate slowly via the partially unfolded
intermediate state, which can be described as an ensemble of hairpin like structures
[6].
Our results contribute to elucidate the mechanism of G quadruplex folding and point
up fundamental questions for the developement of small molecules as G quadruplex
stabilizers in medicinal chemistry.
[1] M. Gellert et al, Proc. Natl. Acad. Sci. USA (1962), 48, 2013-2018.
[2] K. N. Luu et al, J. Am. Chem. Soc. (2006), 128, 9963-9970.
[3] J. X. Dai et al, Nucleic Acids Res. (2007), 35, 4927-4940.
[4] A. T. Phan et al, Nucleic Acids Res. (2007), 35, 19 6517-6525.
[5] K. H. Mok et al, J. Am. Chem. Soc. (2003), 125, 12484 - 12492.
[6] I. Bessi et al, Angew. Chem. Int. Ed. (2015), doi: 10.1002/anie.201502286.
Structure Determination of the SAM/SAH-binding
Riboswitch
A.K. Weickhmann1, H. Keller2, E. Duchardt-Ferner3, C. Kreutz4, J. Wöhnert5
Anna Katharina Weickhmann, [email protected]
1-3, 5 Inst. for Mol. Bioscience / Center of Biomol. Magn. Resonance (BMRZ),
Goethe University Frankfurt, Frankfurt/M, Germany
4 Institute for Organic Chemistry, University of Innsbruck
Riboswitches are highly structured non-coding RNAs that bind small metabolites and
thereby regulate gene expression. Ligands are recognized specifically and selectively,
e.g. closely related metabolites are usually rejected from the RNA.
Here, we investigate the recognition of the metabolic methyl group donor SAM and its
related degradation product SAH by a recently identified SAM/SAH riboswitch that
binds both ligands with comparable affinity [1]. Contrarily, other SAM and SAH
riboswitches selectively and specifically recognize one and repel the other ligand.
The riboswitch was predicted to form a pseudoknot secondary structure. By assigning
the imino proton signals, we were able to delineate the secondary structure. In
addition, one guanine residue was identified in the 2D NOESY spectra to be involved
in non-Watson-Crick base pairing. Further assignments were facilitated by using
samples with site specific 13C-labeling at the aromatic base carbon atoms and by using
a long-range H8C5 HSQC-experiment to assign the base spin systems.
We also synthesized 13C15N-labeled SAH to investigate ligand binding. We used a
combination of HNN-COSY, 2J-1H15N-HSQC and 1H13C HSQC-experiments
recorded for a sample containing 13C15N-labeled SAH bound to 15N-uridine-labeled
RNA to show that the ligand is bound via its Hoogsteen edge. We used site specific
15
N3-uridine labeled RNA to identify the ligand binding uridine as U16.
To determine the structure of the SAM/SAH-binding riboswitch further experiments
are needed to gain insight into the SAH/SAM ligand recognition.
[1] Z. Weinberg, J. X. Wang, J. Bogue, J. Yang, K. Corbino, R. H. Moy and R. R.
Breaker, Genome Biol. (2010), 11, R31.
Conformational flexibility of POTRA domains from
cyanobacterial Omp85 studied by PELDOR
spectroscopy
D. Schuetz1, R. Dastvan2, E.M. Brouwer3, O. Mirus4, E. Schleiff5, T.F. Prisner6
Denise Schuetz, [email protected]
1, 6 Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt,
2 Department of Molecular Physiology & Biophysics, Vanderbilt University,
Nashville, USA
3-5 Department of Molecular Cell Biology of Plants, Goethe University Frankfurt,
Frankfurt/M
The high sensitivity of electron paramagnetic resonance (EPR) spectroscopy makes it
a valuable tool to study site-specific nitroxide-labeled macromolecules in frozen
solution.[1] For example, in doubly spin-labeled membrane proteins dipolar couplings
the unpaired electron spins separated by 1.8 to 6 nm between can be investigated
using Pulsed Electron-Electron Double Resonance (PELDOR)[2] spectroscopy. This
study uses PELDOR spectroscopy to investigate the conformational flexibility
between the polypeptide-transport-associated (POTRA) domains of the outer
membrane protein 85 (Omp85) from cyanobacterium Anabaena sp. PCC 7120. It is
believed that the N-terminal POTRA domains (P1 and P2) are involved in substrate
recognition and hetero-oligomerization. Whereas the C-terminal POTRA domain P3 is
implied regulation of protein transport.[3] The experimental EPR results are compared
to molecular dynamics (MD) simulations and the X-ray structure.
[1] W. Hubbell, et al., Curr. Opin. Struct. Biol. (1998), 8 (5), 649-656.
[2] A. D. Milov, et al., Chem Phys Lett (1984), 110 (1), 67-72.
[3] P. Koenig, et al., J. Biolog. Chem. (2010), 285 (23), 18016-18024.
The NMR-Solution Structure of the Lantibiotic
Immunity Protein NisI
C. Hacker1, N.A. Christ2, E. Duchardt-Ferner3, L. Berniger4, S. Düsterhus5,
U.A. Hellmich6, P. Koetter7, K.-D. Entian8, J. Wöhnert9
Carolin Hacker, [email protected]
1-3, 9 Institute for Molecular Biosciences, Center of Biomolecular Magnetic
Resonance (BMRZ), Goethe University Frankfurt, Frankfurt/M, Germany
4, 5 Institute for Molecular Biosciences, Goethe University Frankfurt
6 Center of Biomolecular Magnetic Resonance (BMRZ) / Institute of Pharmacy and
Biochemistry, Gutenberg University Mainz, Germany
7, 8 Institute for Molecular Biosciences, Goethe University Frankfurt
Lantibiotics like nisin and subtilin are ribosomally synthesized and posttranslational
modified peptides with high antimicrobial activity against Gram-positive bacteria
including pathogens like methicillin-resistant Staphylococcus aureus (MRSA) [1,2].
They achieve their bacteriocidal activity through inhibition of cell wall biosynthesis
by binding to lipid II and lipid II-dependent pore formation in the bacterial membrane
[3]. The Gram-positive lantibiotic producer strains need to protect themselves against
their own lantibiotics. The lipoprotein NisI and the ABC transporter NisFEG confer
immunity to the nisin producer strain L. lactis. How these proteins confer immunity is
still unclear. Therefore, structural studies of these proteins are required. The first
structure of any LanI protein was recently solved by solution NMR for SpaI – a
protein which confers immunity to subtilin producing B. subtilis [4]. While the two
lantibiotics nisin and subtilin are structurally highly similar the associated immunity
proteins NisI and SpaI have very low sequence homology, differ significantly in size
and are not able to confer cross immunity against the two lantibiotics. Here we present
the solution NMR structure of NisI. The structure shows that - in contrast to SpaI NisI is a two domain protein with one domain binding to membranes and a second
domain which is able to bind nisin. Surprisingly, both domains show unexpected
structural similarities to SpaI suggestive of an evolutionary relationship between the
two proteins.
[1] N. Schnell, et al., Nature. (1988), 333(6170), 276-278.
[2] C. Piper, et al., Curr. Drug Discov. Technol. (2009), 6(1), 1–18.
[3] E. Breukink, B. de Kruijff, Nat Rev Drug Discov. (2006), 5(4), 321–323
[4] N. A. Christ, et al., JBC (2012), 287(42), 35286-3528698.
Investigation of the i-motif DNA structure
L. Lannes1, H. Schwalbe2
Laurie Lannes, [email protected]
1, 2 Institut für Organische Chemie und Chemische Biologie / Zentrum für
Biomolekulare Magnetische Resonanz, Goethe University Frankfurt, Germany
i-Motif and G-quadruplex are tetraplexes DNA structures exclusively formed by Cand G-rich sequences respectively. Due to their complementary sequences they are
found together in genome in specific locations suggesting a biological relevance.
The few NMR-based structures of monomeric i-motif rely on samples at natural
abundance containing mutations or modified nucleobases in order to reduce the
sequence redundancy. Such approach is laborious due to signals overlapping; in
addition, the modified nucleobases are suspected to influence the structure [1]. A
solution consists in labelling one dC at a time, leading to a one-peak-reading in NMR
spectra. We applied this strategy to the telomeric sequence [2]. We propose to develop
a method based on biochemical means to produce in tandem uniformly labelled
telomeric i-motif and G-quadruplex sequences for NMR applications.
Direct evidence of the in vivo existence of i-motif structures is still missing,
nevertheless studies demonstrated that i-motif can be formed under physiological
conditions [3]. Recently, the Hurley group discovered a protein, hnRNP LL, able to
bind to the i-motif present into bcl-2 promoter [4]. In addition, by using ligands that
have antagonist effects on i-motif stability, they were able to control bcl-2 expression
in vitro [5]. They hypothesised a binding mechanism that describes a sequential
binding of hnRNP LL domains leading to the i-motif unfolding. We are interested in
better understanding this interaction. Our investigations are based on domains cloning
strategy, interaction assays and NMR spectroscopy.
[1] L. Lannes, S. Halder, Y. Krishnan, H. Schwalbe, Chembiochem( 2015), in press
[2] A. L. Lieblein, et al., H. Schwalbe, Angew (2012), 51, 250-253; A. L. Lieblein, et
al., H. Schwalbe, Angew (2012), 51, 4067-4070
[3] D. Sun, L. H. Hurley, J Med Chem (2009), 52, 2863-2874; J. Cui, P. Waltman, V.
H. Le, E. Lewis, Molecules (2013), 18, 12751-12767
[4] H. J. Kang, S. Kendrick, S. M. Hecht, L. H. Hurley, JACS (2014), 136, 4172-4185
[5] S. Kendrick, et al., L. H. Hurley, JACS (2014), 136, 4161-4171
Structural features of a GTP binding RNA aptamer
A.C. Wolter1, E. Duchardt-Ferner2, K. Hantke3, A.H. Nasiri4, A.K. Weickhmann5,
J. Wöhnert6
Antje Wolter, [email protected]
1-6 Institute for Molecular Biosciences and Center for Biomolecular Magnetic
Resonance (BMRZ), Goethe University Frankfurt, Frankfurt/M, Germany
Aptamers are single-stranded nucleic acids selected in vitro for high-affinity binding
to a wide range of small molecule ligands. The GTP class II aptamer is one of 11
structurally and sequentially very diverse GTP binding RNA aptamers. Despite its
small size of 34 nucleotides it binds GTP with a high affinity with a KD in the
nanomolar range[1].
Based on its sequence the aptamer is predicted to form a bulged hairpin structure with
an upper stem of only two base pairs. We initiated structural studies of the aptamer
GTP-complex by solution NMR in order to gain insight into the structural diversity of
GTP recognition by different aptamers. So far, our NMR-studies revealed additional
long-range tertiary interactions including a Watson-Crick (WC) base-pair between the
apical hairpin loop and the central bulge leading to a considerable compaction of the
structure. The ligand GTP binds to the apical loop and is recognized by an
intermolecular WC base-pair with a conserved cytidine residue and a sugar edge
interaction. The ligand-bound state comprises further interesting structural features:
An adenosine is stably protonated at its N1 position and a guanosine (G) imino group
forms a hydrogen bond to a phosphate group oxygen. Structure calculations of the
aptamer-ligand complex are ongoing[2]. These calculations reveal the presence of a
base triplet adjacent to a base quadruplet at the basis of the ligand binding site. In this
quadruplet, the protonated adenosine’s amino group connects a G-C WC base pair to
the phosphate-interacting G via Hoogsteen hydrogen bonding interactions.
[1] J. M. Carothers, S. C. Oestreich, J. H. Davis and J. W. Szostak, J. Am. Chem.
Soc. (2004), 126, 5130-5137
[2] A. C. Wolter, E. Duchardt-Ferner, A. H. Nasiri, K. Hantke, C. H. Wunderlich, C.
Kreutz and J. Wöhnert, Biomol. NMR Assignments (2015), submitted
Molecular Basis of Microtubule Regulation by
Microtubule-Associated Protein Tau
H. Kadavath1, M. Jaremko2, L. Jaremko3, R. Hofele4, J. Biernat5, S. Kumar6,
K. Tepper7, H. Urlaub8, E. Mandelkow9, M. Zweckstetter10
Harindranath Kadavath, [email protected]
1, 2 Department of NMR based Structural Biology, Max Planck Institute for Biophysical
3, 10 Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Göttingen
4, 8 Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry,
Göttingen
5-7, 9 Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Bonn, Germany
Microtubules regulate cell division, cell morphology, intracellular transport and axonal
stability and therefore play crucial roles in cell function . The structure, dynamic behavior
and spatial organization of microtubules in neurons is regulated by microtubule-associated
proteins [1]. The microtubule-associated protein Tau promotes formation and stabilization
of axonal microtubules and thus influences intracellular transport, axonal stability and cell
morphology . In Alzheimer’s disease the interaction of Tau with microtubules is impaired.
Despite the importance of the regulation of microtubule structure and dynamics by Tau,
very little is known about the interaction of Tau and other microtubule-associated proteins
with microtubules. To fill this gap, we studied the interaction of Tau with microtubules
using a combination of NMR spectroscopy and mass spectrometry. We show that Tau,
which is intrinsically disordered in solution, locally folds into a stable structure upon
binding to microtubules [2]. We further show that Tau promotes microtubule assembly by
binding to protofilaments at the interface between α-β-tubulin heterodimers using small
groups of evolutionary conserved residues [3]. The binding sites are formed by residues
that are essential for the pathological aggregation of Tau, suggesting competition between
physiological interaction and pathogenic misfolding. Collectively, our study establishes a
conserved mechanism of microtubule polymerization and thus regulation of axonal stability
and cell morphology by microtubule-associated protein Tau.
[1] Mandelkow E & Mandelkow E-M (1995) Microtubules and microtubule-associated
proteins. Curr. Opin. Cell Biol. 7(1):72-81.
[2] Kadavath H, et al. (2015) Folding of the Tau Protein on Microtubules. Angew. Chem.
Int. Ed. Engl.
[3] Kadavath H, et al. (2015) Tau stabilizes microtubules by binding at the interface
between tubulin heterodimers. Proc. Natl. Acad. Sci. USA 112(24):7501-7506.
Structural dynamics of a full-length adenine
riboswitch
S. Warhaut1, B. Fürtig2, M. Hengesbach3, P. Höllthaler4, M. Heilemann5,
H. Schwalbe6
Sven Warhaut, [email protected]
1-3 Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and
Chemical Biology, Goethe University Frankfurt, Frankfurt/M, Germany
4, 5 Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt
6 Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and
Chemical Biology, Goethe University Frankfurt
In the human-pathogenic marine bacterium Vibrio vulnificus, the add adenine
riboswitch mRNA (Asw) regulates translation of adenosine deaminase in response to
changes in the intracellular adenine concentration. Translational regulation of Asw is
thermodynamically controlled [1] and temperature-compensated [2] by complex
conformational dynamics: Temperature-dependent secondary structure bistability in
the apo state is coupled to an adenine-dependent conformational switch involving
kissing loop interactions in the aptamer domain and an allosteric melting of secondary
structure at the ribosome binding site in the expression platform.
We employ NMR spectroscopy and single-molecule FRET spectroscopy as
complementary methods to characterize the ligand-dependent conformational
dynamics of full-length (112nt) Asw. By WaterLOGSY experiments on an apoB
stabilized mutant of Asw we could show that the apoB conformation is not involved in
ligand recognition. Via 15N-HSQC spectra of the imino protons we monitor adenineinduced changes in the base pairing of the wild-type RNA. Single-molecule FRET of
immobilized molecules is used to study tertiary interactions that accompany the
observed changes in base pairing. Employing dye-labels on both aptamer domain and
expression platform of Asw we found that the communication between the two
riboswitch domains involves no tertiary contacts. Hence, the allosteric switch in Asw
is strictly decoupled.
[1] J.F. Lemay, G. Desnoyers, S. Blouin, B. Heppell, L. Bastet, P. St-Pierre, E. Massé,
and D.A. Lafontaine, PLoS Genet (2011), 7(1), e1001278.
[2] A. Reining, S. Nozinovic, K. Schlepckow, F. Buhr, B. Fürtig and H. Schwalbe,
Nature (2013), 499(7458), 355-359.
NMR Studies on Intrinsically Disordered Proteins
O. Ohlenschläger1, N. Goradia2, C. Wiedemann3, H. Pospiech4, C. Herbst5, M. Görlach6,
S.H. Heinemann7, R. Ramachandran8
Oliver Ohlenschläger, [email protected]
1-4, 6, 8 Leibniz Institute for Age Research / Fritz Lipmann Institute FLI, Jena, Germany
5 Ubon Ratchathani University, Department of Physics- Faculty of Science, Ubon
Ratchathani, Thailand
7 Friedrich Schiller University Jena & Jena University Hospital, Center for Molecular
Biomedicine - Department of Biophysics, Jena, Germany
An efficient approach to NMR assignments in intrinsically disordered proteins is presented
making use of the good dispersion of cross peaks observed in [15N,13C’]- and [13C’,1H]correlation spectra. The method involves the simultaneous collection of {3D
(H)NCO(CAN)H and 3D (HACA)CON(CA)HA} spectra for backbone assignments via
sequential HN and Halpha correlations and {3D (H)NCO(CACS)HS and 3D
(HS)CS(CA)CO(N)H} spectra for side-chain 1H and 13C assignments, employing
sequential 1H data acquisitions with direct detection of both the amide and aliphatic
protons.
The efficacy of the approach for obtaining resonance assignments with complete backbone
and side-chain chemical shifts is demonstrated experimentally for the 61 residue
[13C,15N]-labelled peptide of a voltage-gated potassium channel protein of the Kv1.4
channel subunit. The alpha subunit of the voltage-gated K+ channel gives rise to
inactivating A-type K+ currents. The process of channel inactivation is mediated by its Nterminal protein structure ("ball-and-chain" domain), which occludes the intracellular entry
of the channel pore to terminate K+ conductance and has potentially to be intrinsically
disordered to reach its receptor site in the internal vestibule of the channel pores.
We further present results of the structure determination of RecQL4 which belongs to the
family of RecQ helicases, a class of proteins initially identified in E. coli and involved in
several aspects of genome maintenance. This molecule consists of structured domains and
intrinsically disordered protein regions. Most RecQ helicases carry a conserved
carboxyterminal domain (RQC) involved in dsDNA interaction and scaffolding. RecQL4
plays a role in the initiation of DNA replication and mutations in RecQL4 are linked to the
Rothmund-Thomson, the RAPADILINO and the Baller-Gerold syndromes characterised by
e.g. skeletal abnormalities or pre-disposition to cancer (osteosarcoma). The N-terminal part
of the human RecQL4 protein adopts a homeodomain fold, binds DNA in a non-sequence
specific manner and interacts with TopBP1. The N–terminal region of RecQL4 bears a
further potential zinc-binding motif (ZBM). Here we report the structure of this second
motif from the mouse RecQL4 sequence where the Asn of the human CxxN motif is
replaced by the more canonical CxxC motif. The additional Cys is highly conserved in
most other species but replaced by Asn in primates.
NMR structure refinement with EPR data
A. Marko1, C.M. Grytz2, S. Kazemi3, P. Güntert4, S.Th. Sigurdsson5, T.F. Prisner6
Andriy Marko, [email protected]
1-4, 6 BMRZ, Goethe University Frankfurt, Frankfurt/M, Germany
5 Science Institute, University of Iceland, Reykjavik, Iceland
Pulsed Electron-Electron Double Resonance (PELDOR) is frequently used to gain
knowledge about the structure and functionality of complex molecules on nanometre
scale. Since most of bio-molecules are diamagnetic, spin labels are attached to them in
order to perform PELDOR experiments. In recent years a growing number of
experiments have been carried out on the systems with the restricted mobility of spin
labels, which enable direct monitoring of the macromolecule conformational
flexibility.[1] Detection of the ensemble of molecular structures that fit experimental
PELDOR data acquired at multiple mw-frequencies and magnetic fields has proven to
be an non trivial task, especially, when no information about molecule under study is
available. This problem can be solved by simulating data base of PELDOR signals for
all possible spin label conformations and inter-spin distances in the experimentally
accessible range.[2] However, the conformational space of the spin labels attached to
complex bio-molecules is significantly restricted due to steric effects. For our work
we have taken the structures of bent DNA molecule calculated by CYANA based on
the NMR data in order to create a subspace of spin label conformers and to fit
PELDOR experimental data.[3] A good agreement of fitting time traces with all
PELDOR signals recorded at X- and Q-band frequencies have been achieved. This
method allows to find structures of bio-molecules which are consistent with NMR and
EPR experiments which are sensitive to the relative orientations of structural
macromolecule domains on nanometer scales.
[1] T. F Prisner, A. Marko, and S. Th. Sigurdsson, J. Magn. Rreson. (2015), 252, 187–
198
[2] A. Marko and T. F. Prisner, Phys. Chem. Chem. Phys. (2013), 15, 619-627
[3] U. Dornberger, A. Hillisch, F. Gollmick, H. Fritzsche, S. Diekmann, Biochemistry
(1999), 38, 12860-12868
Extraction of PRE-restraints from NOESY spectra
E.C. Cetiner1, C. Helmling2, H. Schwalbe3
Erhan Can Cetiner, [email protected]
1-3 Institute for Organic Chemistry and Chemical Biology, Goethe University
Frankfurt , Frankfurt/M, Germany
Paramagnetic relaxation enhancement is commonly used to determine long-ranged
distance restraints for structure calculation of biomolecules. Established methods
usually include expensive isotope labelling in conjunction with spin labelling, where
the need for isotope labelling is based on the HSQC-pulse sequence used. Opposed to
the established methods, we use NOE intensities. A full relaxation matrix approach is
deployed to evaluate the PRE-effect on the NOE-cross peak intensities. The full
relaxation matrix contains experimental as well as theoretical data. An iterative
procedure analogue to IRMA[1,2] is employed since the theoretical data depends on
an initially guessed structure. The procedure was applied to a small model system
(14mer RNA) with different flexible to rigid spin labels to elucidate the influence of
the flexibility on the PRE restraints. Three different approaches were tested to
describe the flexibility of the spin-label: a model-free approach, the averaged and the
minimal distance to the unpaired electron for different conformations. Assuming that
the dynamics of the spin labelled 14mer do not differ highly from the unmodified[3],
the three approaches could be used to decrease the mean absolute and the maximum
error compared to the known structure[4]. A structure calculation was conducted with
manually evaluated PRE distance restraints, resulting in a structure bundle with a
RMSD of 0.516 Å. Most importantly we were able to extract PRE-restraints that were
mostly independent of the guessed structure.
[1] R. Boelens, T. M. G. Koning, and R. Kaptein, J. Mol. Struct., vol. 173, pp. 299–
311, 1988.
[2] R. Boelens, T. M. G. Koning, G. A. van der Marel, J. H. van Boom, and R.
Kaptein, J. Magn. Reson. 1969, vol. 82, no. 2, pp. 290–308, Apr. 1989.
[3] E. Duchardt and H. Schwalbe, J. Biomol. NMR, vol. 32, no. 4, pp. 295–308, Aug.
2005.
[4] S. Nozinovic, B. Fürtig, H. R. A. Jonker, C. Richter, and H. Schwalbe, Nucleic
Acids Res., vol. 38, no. 2, pp. 683–694, Jan. 2010.
Conformational change observed on the radical
transfer pathway of E. coli RNR by high frequency
(94, 263 GHz) EPR, 34 GHz ENDOR and
PELDOR spectroscopy
M. Kasanmascheff1, W. Lee2, T.U. Nick3, J. Stubbe4, M. Bennati5
Müge Kasanmascheff, [email protected]
1, 3, 5 Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany
2, 4 Department of Chemistry, Massachusetts Institute of Technology, Cambridge,
Massachusetts, USA
Escherichia coli class Ia ribonucleotide reductase (RNR) catalyzes the conversion of
nucleotides to deoxynucleotides via a proton-coupled electron transfer (PCET) process
that spans over 35 Å [1, 2]. This long-range PCET among two subunits occurs via a
specific pathway of redox active amino acids (Y122 ↔ [W48?] ↔ Y356 in β2 ↔ Y731 ↔
Y730 ↔ C439 in α2) [3]. The mechanism of PCET at the αβ subunit interface between
Y356 in β2 and Y731 in α2 is still unknown due to lack of any structural information in
this region. To examine the role of R411 on PCET at the subunit interface NH2Y was
site-specifically incorporated at residue 731 and Y731NH2Y-α2 was further modified
with an R411A mutation. NH2Y731• was generated and analyzed by multifrequency (9,
34, 94 and 263 GHz) EPR spectroscopy. We observed an unusual ring dihedral
indicative for structural changes in NH2Y731• in the presence of R411A mutation.
Subsequent ENDOR and PELDOR measurements demonstrated a new conformation
of the observed radical pointing towards the interface. The results revealed the
importance of the off-pathway residue R411 during the unprecedented long-range
PCET in E. coli RNR and provided first experimental evidence for the dynamic nature
of the pathway residue Y731 in the active α2β2 complex [4].
[1]. Uhlin, U., Eklund, H., Nature (1994), 370, 533-539.
[2]. Nordlund, P., Sjöberg, B.M., Eklund, H., Nature (1990), 345, 593-598.
[3]. Minnihan, E.C., Nocera, D.G., Stubbe, J., Accounts of Chemical Research (2013),
46, 2524-2535.
[4]. Kasanmascheff, M., Lee, W., Nick, T.U., Stubbe, J., Bennati, M., in preparation.
Long-time self-diffusion in protein mixtures
forming transient clusters: the applicability of the
Stokes-Einstein relationship
M. Rothe1, M. Roos2, S. Link3, T. Gruber4, A. Krushelnitsky5, J. Balbach6,
K. Saalwächter7
Maik Rothe, [email protected]
1-7 Martin-Luther-University Halle-Wittenberg, Germany
Translational diffusion is the most important transport mechanism in solutions and is
characterized by the long-time self-diffusion coefficient, as described theoretically by
the Stokes-Einstein (SE) equation. Its generalized form relies on the macro-viscosity
of the sample and applies even for highly concentrated colloidal mono-disperse [1]
and mixed [2] systems. Its applicability has also been demonstrated for highly
concentrated single proteins [3,4], yet in case of (concentrated) protein mixtures it has
been questioned [5,6]. We used isotope-filtered pulsed-field gradient (PFG) NMR to
measure the diffusion coefficients of labeled SH3 and BSA in mixtures over a wide
range of concentrations and temperatures, and compare these results to the macroviscosity of the same samples. Except for low concentrations, the SE relationship
appears to be violated. However, the mismatch between translational diffusion
coefficients and the macro-viscosity can be consistently explained by transient binding
of the two proteins on the timescale of the diffusion time of the PFG NMR
measurement, resulting in an apparent change of the hydrodynamic radius in
dependence of temperature and protein concentration. Thus, deviations from the SE
prediction for protein mixtures do not necessarily contradict the broad applicability of
this famous relationship, rather, they can reveal binding phenomena.
[1] P.N. Segrè, S.P. Meeker, P.N. Pusey, and W.C.K. Poon, Phys. Rev. Lett. (1995),
75 (5), 958-961
[2] W. Richtering, and H. Müller, Langmuir (1995), 11, 3699-3704
[3] P. Licinio, and M. Delaye, J. Phys. France (1988), 49, 975-981
(2015), 108, 98-106
[5] Y. Wang, C. Li, and G.J. Pielak, JACS (2010), 132, 9392–9397
[6] S. Zorrilla, M.A. Hink, A.J.W.G. Visser, and M.P. Lillo, Biophys. Chem. (2007),
125, 298-305
Structural and functional insights into PaMTH1:
a longevity assurance factor
D. Chatterjee1,2, D. Kudlinzki1,2,3,4, V. Linhard1,2, K. Saxena1,2,3,4, U. Schieborr1,2,3,4,
S.L. Gande1,2,3,4, J.P. Wurm2,5, J. Wöhnert2,5 , R. Abele6, V.V. Rogov2,7, V. Dötsch2,7,
H.D. Osiewacz5, S. Sreeramulu1,2, H. Schwalbe1,2,3,4
Deep Chatterjee, [email protected]
1 Inst. of Org. Chem. and Chemical Biol., Goethe University Frankfurt
2 Center for Biomolecular Mag. Resonance (BMRZ), Goethe University Frankfurt
3 German Cancer Consortium (DKTK), Heidelberg
4 German Cancer Research Center (DKFZ), Heidelberg
5 Inst. of Molecular Biosciences, Goethe University Frankfurt
6 Inst. of Biochemistry, Biocenter, Goethe University Frankfurt
7 Inst. of Biophysical Chemistry, Goethe University Frankfurt
Oxidative stress plays a key role in the regulation of cell metabolism and is considered
as an important factor in both cancer development and responses to treatment
strategies. Additionally, the redox state of the cancer cells can differ from that of the
normal cells. Reactive oxygen species (ROS) are generally detrimental to the cells and
hence many signaling molecules in the cells are associated with ROS regulation.
Several polyphenols in general including flavonoids have the potential to generate
hydroxyl radicals, the most hazardous among all ROS. However, the generation of
hydroxyl radical and subsequent ROS formation can be prevented by methylation of
the hydroxyl group. O-methylation is performed by O-methyltransferases which are
members of the S-adenosylmethionine (SAM)-dependent O-methyltransferase
superfamily involved in the secondary metabolism of many species across all
kingdoms. Interestingly, in the filamentous fungus Podospora anserina, a wellestablished ageing model, O-methyltransferase (PaMTH1) was reported to accumulate
in total and mitochondrial protein extracts during ageing. Here, we present the crystal
structure of PaMTH1 and biophysical insights into the enzyme catalyzed methyl
transfer reaction from the co-factor (SAM) to the flavonoid.
D. Chatterjee, D. Kudlinzki, V. Linhard, K. Saxena, U. Schieborr, S. L. Gande, J.
Philip Wurm, J. Wöhnert, R. Abele, V. V. Rogov, V. Dötsch, H. D. Osiewacz, S.
Sreeramulu, and H. Schwalbe, J. Biol. Chem. (2015), 290, 16415-16430.
Structural basis of the interaction of the TRPV4
ion channel with its protein and lipid functional
modulators
N.A. Christ1, B. Goretzki2, E. Duchardt-Ferner3, R. Gaudet4, U.A. Hellmich5
Nina A. Christ, [email protected]
1, 2, 5 Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz
/ Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt
2 Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz;
Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt
3 Institute for Molecular Bioscience, Center of Biomolecular Magnetic Resonance,
Goethe University Frankfurt
4 Department of Molecular and Cellular Biology, Harvard University
Transient receptor potential (TRP) channels are the second largest ion channel family
in mammals with remarkable functional diversity. The TRPV (vanilloid) channel
subfamily in particular has a role in temperature and pain sensation. Mutations in the
human TRPV4 gene cause skeletal dysplasias or/and motor and sensory neuropathies.
Understanding the role of TRPV4 in these very divergent groups of diseases is not
only important for treatment of these diseases but might help to elucidate the function
of the channel involvement in different signaling cascades. In addition to a sixtransmembrane helix domain, TRP channels possess diverse cytosolic regions thought
to serve as channel regulators and as docking stations for various effector molecules.
In TRPV4, binding sites for Pacsin3, a protein involved in synaptic vesicular
membrane trafficking and endocytosis, and PIP2, a lipid messenger, co-localize to a
small stretch within the TRPV4 N-terminus. The interplay of lipids and cytoplasmic
proteins as regulators of complex ion channels may well be a general theme in TRP
channels and explain some of their intricate behaviors. For TRPV4, PIP2 acts as a
sensitizer while Pacsin3 desensitizes the channel to stimuli such as heat.
Here we present the solution NMR structure of the Pacsin3 SH3 domain bound to the
N-terminal proline rich region of TRPV4 and first insights into the regulation of this
interaction by phosphoinositides.
Time-resolved NMR-spectroscopy extended to the
µs-timescale
F. Lehner1, A. Cherepanov2, H. Schwalbe3
Florian Lehner, [email protected]
1-3 Schwalbe Group, Center for Biomolecular Magnetic Resonance (BMRZ), Institute
for Organic Chemistry and Chemical Biology, Goethe University Frankfurt
Protein folding is one of the most fascinating processes in structural biology. Errors in
this process, e.g. misfolding and aggregation often lead to human disorders[1]. While
the unfolded or folded protein structures are often relatively well characterized, less is
known on the structure of folding intermediates. SOFAST NMR, mixing- and laserpulsed techniques have been developed, giving a glance on the millisecond structural
changes[2,3]. The development of new techniques is a must for further
characterizations in the millisecond and especially down to the microsecond time
domain, where crucial mechanistic insights in molecular folding and catalysis can be
obtained. Here we implement novel fast too ultrafast freeze-hyperquenching
techniques. The process of interest is either triggered in nanoseconds by mixing the
reactants in the tangential micromixer or induced by heating the sample within
milliseconds while the sample passes a heated nozzle[4]. The reaction intermediates
are frozen out in liquid cryomedium with a time resolution down to microseconds.
The preliminary results are presented.
[1] C. Soto, FEBS Letters, (2001),498, 204-207
[2] P. Schanda, Ē. Kupče, B. Brutscher, J. Biomol NMR, December (2005), Volume
33, Issue 4, pp 199-211
[3] K. Hun Mok, T. Nagashima, I. J. Day, J. A. Jones, C. J. V. Jones, C. M. Dobson,
and P. J. Hore, , J. Am. Chem. Soc. (2003), 125, 12484-12492
[4] A.V. Cherepanov, S. De Vries, Biochimi. Biophys. Acta, (2004), 1656, 1-31
NMR Spectroscopic Characterization of DNA GQuadruplexes: Structural Features of Truncated
c-myc Sequences
B. Karg1, K. Weisz2
Beatrice Karg, [email protected]
1, 2 Analytical Biochemistry, Institute for Biochemistry, Ernst-Moritz-ArndtUniversität Greifswald
Depending on sequence and environmental conditions G-rich sequences can form a
variety of structures with a G-tetrad scaffold. Being a prominent example of such
sequences, part of the promoter region of the c-myc oncogene can fold into a welldefined, monomolecular parallel quadruplex [1]. The 3'- and 5'-termini of this c-myc
sequence are not part of the G-tetrads but provide a capping overhang. Truncation of
the terminal bases should yield important insights into the impact of these caps with
respect to structural stability and ligand binding provided that well-defined structures
are still formed. A corresponding structural characterization of the truncated c-myc
sequences has been performed by NMR spectroscopic techniques.
While NOESY spectra of unlabeled DNA mainly provide sequential contacts for each
of the four G-runs, heteronuclear long-range coupling experiments with JR solvent
suppression (JRHMBC) allow an unambiguous assignment of imino protons [2].
Additional HSQC experiments were used to identify the conformation of bases. Thus,
three truncated c-myc sequences could be characterized without the use of expensive
13
C and 15N isotope labeling.
[1] A. Ambrus, D. Chen, J. Dai, R.A. Jones, D. Yang, Biochemistry (2005), 44(6),
2048-2058.
[2] A.T. Phan, Journal of Biomolecular NMR (2000), 16, 175-178.
Monitoring conformational changes of
biomacromolecules in cellula with Gd(III)-based
spin labels by Q-band DEER
A. Groß1, M. Qi2, A. Godt3, M. Drescher4
Andreas Groß, [email protected]
1, 4 Department of Chemistry, and KoRS-CB, University of Konstanz, Germany
2, 3 Faculty of Chemistry and Center for Molecular Materials, Bielefeld University,
Germany
The determination of structure and dynamics of biomacromolecules like proteins in
their natural environment is crucial for understanding their function. Double electronelectron resonance (DEER) in combination with site-directed spin labeling allows incell EPR to investigate the structure of spin labeled biomacromolecules in the cellular
environment.
However, intracellular application of EPR is often hampered by the short intracellular
life-time of the commonly used nitroxide spin labels.[1-3] To overcome this
limitation, we introduce Q-band DEER with Gd(III) based spin labels for intracellular
distance measurements inside oocytes of Xenopus laevis.
We observed a conformational change of the polyproline peptide H-AP10CP10CP10NH2 in cellula, suggesting an insertion of the polyproline peptide into cell membranes
coinciding with a conformational change of the polyproline-helix type II to type I,
which was not be observed in cell extract. Thus, this study shows that in-cell EPR
distance measurements are capable to monitor conformational changes in cellula.[4]
[1] R. Igarashi, T. Sakai, H. Hara, T. Tenno, T. Tanaka, H. Tochio, M. J. Shirakawa,
Am. Chem. Soc. (2010), 132, 8228.
[2] I. Krstić, R. Hänsel, O. Romainczyk, J. W. Engels, V. Dötsch, T. F. Prisner,
Angew. Chem. Int. Ed. (2011), 50, 5070.
[3] M. Azarkh, V. Singh, O. Okle, I. T. Seemann, D. R. Dietrich, J. S. Hartig, M.
Drescher, Nat. Protoc. (2013), 8, 131.
[4] M. Qi, A. Groß, G. Jeschke, A. Godt, M. Drescher, J. Am. Chem. Soc. (2014),
136, 15366.
Automatic assignment of methyl-TROSY spectra
from NOEs
I. Pritisanac1, M.T. Degiacomi2, A.J. Baldwin3
Iva Pritisanac, [email protected]
1-3 University of Oxford, Department of Physical and Theoretical Chemistry
Combining advanced methyl nuclear spin labelling strategies with transverse
relaxation-optimized spectroscopy (TROSY) enables analysis of functional dynamics
in large proteins. However, the manual assignment of methyl-TROSY HMQC spectra
is a major bottleneck to its wider applications. Here, we present an algorithm that
solves methyl resonance assignment as a maximum common subgraph (MCS)
problem[1].
A structural model and distance threshold are used to compute a structure graph of
methyl-containing residues (nodes) and their inter-methyl connections (edges), while
1
H-13C correlations (nodes) and inter-methyl NOEs (edges) define the NOE graph. In
proof–of–principle calculations on cyclic-dependent kinase 2 (34 kDa), we show that,
given only very sparse simulated NOEs, the algorithm assigns 75% resonances with
100%, 16% with 50% (2 equally likely assignment options) and 9% with 33%
confidence, respectively.
When applied to experimental NOE data for ubiquitin, 90% of the ILV residues were
assigned with 100% confidence and 10% with 50% confidence. In a more challening
system, a dimer of aspartate transcarbamoylase (30 kDa), we assigned 39% of methyl
resonances with 100% confidence, 42% with 50% confidence and 19% as highly
ambiguous.
Performance comparison to two other automatic algorithms[2,3] shows the advantages
of the MCS approach in both accuracy and confidence of the assignments. The
exactness of our approach guarantees the correctness of the confident assignments and
highlights residues for which more experimental information is needed to resolve
ambiguities.
[1] McGregor, JJ. (1982). Software Practice and Experience, 12, 23-34.
[2] Chao, FA; Kim, J; Xia, Y; Milligan, M; Rowe, N; Veglia, G. (2014) J. Mag. Res.,
245, 17-23.
[3] Xu, Y; Matthews, S. (2013) J. Biomol. NMR, 55, 179–187
Automatic resonance assignment of intrinsically
disordered proteins with the TSAR program
A. Zawadzka-Kazimierczuk1, S. Żerko2, S. Saxena3, W. Koźmiński4, M. Billeter5,
R. Konrat6, L. Geist7, G. Platzer8, D. Kurzbach9, Z. Orbán-Németh10
Anna Zawadzka-Kazimierczuk, [email protected]
1-4 University of Warsaw, Faculty of Chemistry, Biological and Chemical Research
Centre, Warsaw, Poland
5 Biophysics Group, Department of Chemistry and Molecular Biology, University of
Gothenburg, Gothenburg, Sweden
6-8, 10 Max F. Perutz Laboratories, Department of Computational and Structural Biology,
University of Vienna, Vienna, Austria
9 Max Planck Institute for Polymer Research, Mainz, Germany
NMR is the primary method of studying intrinsically disordered proteins (IDPs). However,
resonance assignment is in this case a more demanding task than for folded proteins. The
particularly narrow chemical shift range often makes the routinely-used 3D spectra
insufficient. On the other hand, the low relaxation rates makes spectra of high
dimensionality feasible. Such spectra can be recorded using non-uniform sampling, which
provides spectra of extraordinary resolution. The data processing can be performed using
sparse multidimensional Fourier transform (SMFT) [1] based on the concept of fixing some
of the spectral dimensions to the frequencies known from the basis spectrum, acquired in
advance. As a result, a set of 2D cross-sections of the multidimensional spectrum is
obtained. The parallel analysis of the cross-sections of various spectra allows to achieve the
resonance assignment. The TSAR program [2] automates this process.
Here we demonstrate the utility of the TSAR program for automatic assignment of
resonances of IDP samples. The TSAR program, being dedicated to the analysis of 2D
cross-sections, exploits all advantages of the SMFT input. Its flexibility allows to process
data from any set of experiments that provide sequential connectivities. The program’s
performance for several high-resolution demanding IDP samples ([3-5] and three yet
unpublished) is demonstrated. In all the cases, reliable assignment of the majority of
resonances was achieved. The program's output supports manual completion of the
assignment process.
[1] K Kazimierczuk, et al., J Magn Reson (2009), 197, 219–228.
[2] A Zawadzka-Kazimierczuk, et al., J Biomol NMR (2012), 54, 81–95.
[3] L Geist, et al., Biomol NMR Assign (2013), 7, 315-319.
[4] Z Orbán-Németh, et al., Biomol NMR Assign (2014), 8, 123-127.
[5] G Platzer, S Żerko, S Saxena, W Koźmiński, R Konrat, Biomol NMR Assign (2015), in
print.
Analysis of conformational changes in the
substrate binding protein of a TRAP transporter
from V. cholerae by PELDOR spectroscopy and
X-ray crystallography
J. Glaenzer1, G. Hagelueken2
Janin Glaenzer, [email protected]
1, 2 Structure, Function & Dynamics of Macromolecules, Institute for Physical and
Theoretical Chemistry, University of Bonn
TRAP transporters are an important class of ATP-independent membrane transporters
in bacteria. They are composed of one or two transmembrane domains and a
periplasmic substrate binding protein (SBP). The SBP scavenges its substrate, e.g. a
sialic acid, from the environment and delivers it to the transporter. Binding of the SBP
to the transporter is believed to trigger conformational changes that ultimately lead to
the translocation of the substrate. X-ray structures of the SBP in the presence and
absence of its substrate revealed the existence of an open and closed conformation of
the SBP.
For an efficient transport process, only the substrate loaded (closed) SBP should bind
to the transporter. It is thus interesting to investigate whether the conformational
changes of the SBP are strictly substrate induced or if the molecule constantly samples
the open-, closed- or possibly intermediate conformations.
We aimed to answer this question using EPR distance measurements on the SBP SiaP
from V. cholerae. We used the “difference distance matrix” feature of mtsslWizard to
find optimal spin labelling positions on the molecular surface of SiaP. High quality
PELDOR data of the spin labelled SBP were recorded in the presence and absence of
its substrate. Further, the conformation of the spin label on the molecular surface or
the SBP was analysed by X-ray crystallography. Our results reveal new insights into
the conformational state of the SBP in frozen solution.
Transiently stable antiterminator guarantees gene
expression in transcriptional riboswitch
H.S. Steinert1, A. Wacker2, J. Buck3, F. Hiller4, J. Noeske5, S. Grimm6, B. Fürtig7,
H. Schwalbe8
Hannah Steinert, [email protected]
1-8 Center for Biomolecular Magnetic Resonance, Institute for Organic Chemistry
and Chemical Biology, Goethe University Frankfurt, Germany
Riboswitches [1-3] are gene regulatory mRNA elements. For transcriptional
riboswitches, ligand binding to the aptamer domain supposedly induces a
conformational switch between the mutually exclusive antiterminator and terminator
conformations that represent the on- and off-states of the switch, respectively. Here,
we show that the full-length transcriptional guanine- and hypoxanthine-sensing xptpbuX riboswitch from Bacillus subtilis [4] adopts the terminator conformation (offstate) at thermodynamic equilibrium independent of the ligand. In contrast to the fulllength mRNA, transcription intermediates undergo ligand-dependent conformational
changes. Importantly, in the absence of ligand, the RNA was able to adopt the
antiterminator conformation in a transcription intermediate. The conformation was
kinetically trapped and did not refold fast enough to form the longer and more stable
terminator conformation in the limited timeframe available during transcription. This
kinetic trapping allows the RNA-polymerase to escape from the termination site
before the terminator is folded and to maintain gene expression in the absence of
ligand. In the presence of ligand, ligand binding early during transcription stabilised
the aptamer domain, suppressed the formation of the antiterminator conformation,
and, thus, accelerated formation of the terminator conformation by at least two orders
of magnitude, leading to gene repression.
[1] A. S. Mironov, I. Gusarov, R. Rafikov, L. E. Lopez, K. Shatalin, R. A. Kreneva,
D. A. Perumov, E. Nudler, Cell (2002), 111 (5), 747-756
[2] A. Nahvi, N. Sudarsan, M. S. Ebert, X. Zou, K. L. Brown, R. R. Breaker,
Chemistry & Biology (2002), 9 (9), 1043-1049
[3] W. C. Winkler, A. Nahvi, R. R. Breaker, Nature (2002), 419 (6910), 952-956
[4] M. Mandal, B. Boese, J. E. Barrick, W. C. Winkler, R. R. Breaker, Cell (2003),
113 (5), 577–586
mtsslWizard: Finding optimal spin labelling
positions using difference distance matrices
G. Hagelueken1, D. Abdullin2, O. Schiemann3
Gregor Hagelueken, [email protected]
1-3 Institute for Physical and Theoretical Chemistry, University of Bonn
In silico spin labelling is widely used for the interpretation of EPR-based distance
distributions. It is also very useful during the planning stages of spin labelling
experiments, for example to find suitable labelling positions.
The latest version of mtsslWizard (v.1.3), includes new features, which were designed
to assist users with the identification of optimal labelling positions. For this purpose,
the program calculates distance matrices (DMs) which reveal all possible label-label
distances for a particular protein. DMs are a very convenient way of finding label
pairs that will produce distances, which are easily measurable with e.g. PELDOR
spectroscopy. If multiple models are available for a particular protein (for example in
two conformational states), the program calculates a DM for each state and subtracts
the two DMs to produce a difference distance matrix (DDM). Regions with large
conformational changes are easily identified in DDMs and represent promising
labelling positions.
The calculation of the DMs and DDMs with mtsslWizard is very user-friendly and
only requires two mouse clicks. The spin labelling algorithm was optimised, so that
the calculation of a complete DM or DDM for a 300 residue protein only takes a few
seconds on a standard laptop computer. Additional new features of the mtsslWizard
include a labelling site accessibility estimation, a plotting tool (mtsslPlotter) and
additional spin labels such as the trityl spin label.
Trityl Radicals: Spin Labels for Distance
Measurement in Proteins at Physiological
Temperatures
J.J. Jassoy1, A. Berndhäuser2, O. Schiemann3
Jean Jacques Jassoy, [email protected]
Triarylmethyl-radicals (Trityl) are highly persistent radicals, which are of interest for
current developments of spin-labels for EPR-based distance measurements. Compared
to nitroxide spin-labels, which are presently the most commonly used spin-labels for
distance measurements, they show several advantages.[1-3] Most important among
these are their narrow spectral width, their comparatively long relaxation time and
their persistence even in reducing environments, which give rise to the hope that they
may in the future be used for pulsed room temperature measurements within whole
cells.[4] Here, we describe synthetic approaches to trityl spin-labels for the specific
purpose of labeling proteins for EPR distance measurements and we show results for
distance measurements with these trityls.
[1] Z. Yang, Y. Liu, P. Borbat, J. L. Zweier, J. H. Freed and W. L. Hubbell, J. Am.
Chem. Soc. (2012), 134, 9950.
[2] G. W. Reginsson, N. C. Kunjir, S. Th. Sigurdsson and O. Schiemann, Chem. Eur.
J. (2012), 18, 13580.
[3] N. C. Kunjir, G. W. Reginsson, O. Schiemann and S. Th. Sigurdsson, Phys. Chem.
Chem. Phys. (2013), 15, 19673.
[4] G. Y. Shevelev, O. A. Krumkacheva, A. A. Lomzov, A. A. Kuzhelev, O. Y.
Rogozhnikova, D. V. Trukhin, T. I. Troitskaya et al., J. Am. Chem. Soc. (2014), 136,
9874.
Conformations of the cocaine aptamer studied by pulsed
electron-electron double resonance (PELDOR)/ double
electron-electron resonance (DEER) spectroscopy
C.M. Grytz1, A. Marko2, P. Cekan3, S.Th. Sigurdsson4, T.F. Prisner5
Claudia Maria Grytz, [email protected]
1, 2, 5 Inst. of Phys. and Theo. Chem., BMRZ, Goethe University Frankfurt, Germany
3, 4 Department of Chemistry, University of Iceland, Reykjavik, Iceland
The cocaine aptamer is a DNA 3-way junction that binds cocaine at its helical junction.[1]
We studied the global conformation and overall flexibility of the aptamer in the absence
and presence of cocaine by PELDOR[2,3]. The rigid nitroxide spin label Ç[4] was
incorporated pairwise into two helices of the aptamer. Multi-frequency 2D PELDOR
experiments allow the determination of the mutual orientation[5] and the distances between
two Çs. Since Ç moves dependent from the helix to which it is attached, it directly reports
on the aptamer dynamics. The cocaine-bound and the non-bound states could be
differentiated from the global conformational flexibility, which decreases upon binding to
cocaine, as judged by changes in our PELDOR time traces. A small change in the width
and mean distance of the distribution was observed upon cocaine binding. Further
structural insights were obtained by investigating the relative orientation between two Çs
and thereby of the relative orientation between two stems. Although, 2D PELDOR data
performed at X-band frequencies do not contain information on all the Euler angles
describing the relative orientation between two Çs.[7] The bent angle between two stems
could be precisely determined. However, their twist angles cannot be described solely using
the orientation parameters from X-band data. Therefore we combined the orientation
information with a priori knowledge about the secondary structure of the aptamer. A
molecular model describing the global folding and flexibility of the cocaine aptamer
assuming the helixes as rigid bodies was obtained.
[1] Stojanovic, M.N., de Prada, P. and Landry, D.W. J. Am. Chem. Soc. 2000, 122, 11547.
[2] Milov, A. D.; Salikhov, K. M.; Shchirov, M. D. Sovietscaya Physics Solid Stated 1981,
23, 565.
[3] Schiemann, O.; Prisner, T. F. Quart. Rev. Biophys. 2007, 40, 1.
[4]a) Barhate, N.; Cekan, P.; Massey, A. P.; Sigurdsson, S. Th. Angew. Chem. Int. Ed.
2007, 119, 2709
b) Barhate, N.; Cekan, P.; Massey, A. P.; Sigurdsson, S. Th. Nucleic Acids Res. 2008, 36,
5946.
[5] Schiemann, O., Cekan, P., Margraf, D., Prisner, T.F. and Sigurdsson,
S.Th. Angew. Chem. 2009, 48, 3292.
263-GHz pulsed EPR, 94-GHz ENDOR Spectroscopy and
DFT Calculations Differentiate Hydrogen Bond Networks
in Proton-Coupled Electron Transfer Steps of E. Coli
Ribonucleotide Reductase Ia
T.U. Nick1, W. Lee2, K. Ravichandran3, S. Kossman4, M. Kasanmascheff5, F. Neese6,
J. Stubbe7, M. Bennati8
Thomas Nick, [email protected]
1, 5, 8 Electron Spin Resonance Group, Max Planck Institute for Biophysical
2, 3, 7 Stubbe Group, Department of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts, USA
4, 6 Abteilung Molekulare Theorie und Spektroskopie, Max Planck Institute for
Chemical Energy Conversion, Mülheim an der Ruhr, Germany
Ribonucleotide reductases (RNR) connect the RNA and the DNA world via strictly
controlled radical chemistry that reduces all four essential ribonucleotides to
deoxyribonucleotides. In RNR Ia, the reaction starts at the “stable” tyrosyl radical
(Y122•) di-iron cofactor. Successive studies showed that Y356•(β) Y731•( α) and Y730•(
β) are intermediate steps of an inter-subunit proton-coupled electron-transfer (PCET),
before a catalytic cysteine radical (C439•) is formed in the α subunit. Conformational
gating hinders the direct observation of these transient radicals. Site specific
incorporation of the unnatural 3-amino-tyrosine (NH2Y) and 2,3,5-F3Y was used to
trap all radical intermediates [1,2]. 263-GHz EPR spectroscopy delivers highly
resolved g values, which were correlated to the individual hydrogen (H) bond network
based on ENDOR spectroscopy and DFT models of the radical intermediates. For
short PCET steps moderate to strong H bonds perpendicular to the ring were found,
consistent with a concerted PCET [3,4]. At wt-β-Y356• an orthogonal PCET is
proposed. Here only in-plane moderate H bonds (1.9±0.1 Å) could be observed. DFT
models, consistent with the obtained g values, proposed an additional weak H bond
(>2.1 Å). The in-plane H bonds are mechanistically in sharp contrast to perpendicular
H bonds found in the collinear PCET in the α subunit [3,4]. Overall our data illustrate
that H bond networks across the subunit interface disfavors a collinear PCET. This is
the first spectroscopic distinction between orthogonal and short collinear PCET steps.
[1] E. C. Minnihan, et al., J. Am. Chem. Soc. (2011), 133, 9430-9440.
[2] E. C. Minnihan, et al., J. Am. Chem. Soc. (2011), 133, 15942-15945.
[3] T. U. Nick, et al., J. Am. Chem. Soc. (2015), 137, 289-298.
[4] T. Argirević, et al., J. Am. Chem. Soc. (2012), 134, 17661-17670.
PELDOR on Trimeric Betaine Symporter BetP
B. Endeward1, I. Waclawska2, C. Ziegler3, T.F. Prisner4
Burkhard Endeward, [email protected]
1, 4 Institute of Physical and Theoretical Chemistry and Center for Biomolecular
Magnetic Resonance BMRZ, Goethe University Frankfurt, Germany
2 Max Planck Institute of Biophysics, Department of Structural Biology, Frankfurt,
Germany.
3 University Regensburg, Department of Biophysics II, Regensburg, Germany.
PELDOR (pulsed electron electron double resonance [1]) is a magnetic resonance
method for distance, orientation, and dynamic measurements of two or more
paramagnetic centers in macromolecules like proteins, RNA, or DNA as well as
polymers. Here we apply this method to analyze the different states of the trimeric
betaine symporter BetP [2-3]. This symporter does activate at osmotic stress and
transports betaine and sodium through the membrane. BetP cycles through several
states during the transport. From the periplasmic open via an occluded to a
cytoplasmic open state. One open question on the trimeric transport is whether it
occurs on all three monomers synchronously or in a cyclic sequence. By PELDOR
and site-directed spin labeling we probe the changes on activation as well as the
occurring different states. We will report on the current status at this ongoing project.
This work is financially supported by DFG-CRC 807, BMRZ and Goethe University.
[1] A. Milov, K. Salikov, M. Shirov, Fiz. Tverd. Tela., 1981 (23) 975-982.
[2] S. Ressl, A.C. Terwisscha van Scheltinga, C. Vonrhein, V. Ott, C. Ziegler,
Molecular basis of transport and regulation in the Na(+)/betaine symporter BetP
Nature 2009 (458) 47-52.
[3] L. Forrest, R. Krämer, C. Ziegler, The structural basis of secondary active
transport mechanisms. Biochim Biophys Acta 2011 (1807) 167-188.
The NMR solution structure of cell-penetrating
cyclic peptides in membrane mimetic agents
F. Reichart1, M. Horn2, S. Natividad-Tietz3, I. Neundorf4, D. Diaz5
Dolores Díaz, [email protected]
1-4 Institute of Biochemistry, Department of Chemistry, University of Cologne
5 NMR facility, Department of Chemistry, University of Cologne
Although cellular membrane can be traversed by small-molecule drugs via passive
diffusion or it is mediated by membrane receptor-drug interactions, from a
medicinal/pharmacological view point, a more efficient and controlled transportation
of exogenous bioactive molecules through plasma membrane is desirable. The use of
molecular transporters to transfer therapeutic agents into living cells has been
envisaged as an interesting approach to improve drug cellular internalization
efficiency.[1]
Among those, the so-called cell-penetrating peptides (CPP) are currently receiving
much attention since their composition, structure and physicochemical properties can
be adapted to the molecule to be transferred. Thus, amphipathic peptides seem to
interact better with plasma membranes and, recently, cyclization of the peptide
backbone (i.e. rigidification) has been described as one strategy to obtain CPPs with
high uptake rates and enhanced cytoplasmic accumulation.[2]
CAP18 is a natural antibacterial peptide and, recently, the versatility of a related
peptide, namely sC18, for the transport of organometalic complex-peptide conjugates
has been demonstrated.[3] To improve the interaction of sC18 with the cellular
membrane, we have synthesized a series of cyclic sC18 peptide derivatives. The
cyclization occurs between side chains with inclusion of a triazole moiety. Herein, an
NMR based structural study of those cyclic CPPs in solution and in the presence of
micelles is presented.
[1] F. Wanga, Y. Wanga, X. Zhanga, W. Zhanga, S. Guoa, F. Jin, Journal of
Controlled Release (2014), 174, 126–136.
[2] G. Lattig-Tunnemann, M. Prinz, D. Hoffmann, J. Behlke, C. Palm-Apergi, I.
Morano, H. D. Herce, M. C. Cardoso, Nature communications (2011), 2, 453.
[3] K. Splith, W. Hu, U. Schatzschneider, R. Gust, I. Ott, L. A. Onambele, A. Prokop,
I. Neundorf, Bioconjugate chemistry (2010), 21, 1288-1296.
More than Binding – Attachment of human
Noroviruses to Histo Blood Group Antigens
A. Mallagaray1, J. Lockhauserbäumer2, S. Weissbach3, G. Dominguez4, G. Hansman5,
C. Utrecht6, J. Pérez-Castells7, T. Peters8
Alvaro Mallagaray, [email protected]
1, 3, 8 Center of Structural and Cell Biology in Medicine, Institute of Chemistry,
University of Lübeck, Lübeck, Germany
2, 6 Dynamics of viral Structures, Heinrich Pette Institute, Leibniz Institute for
Experimental Virology, Hamburg, Germany
4, 7 Facultad de Farmacia, Dpto. Química, Universidad San Pablo CEU, Madrid, Spain
5 Schaller Research Group at the University of Heidelberg and the DKFZ Heidelberg,
Germany
Acute gastroenteritis causes the second greatest burden of all infectious diseases, estimated
at 1.45 million deaths worldwide every year. Human Noroviruses (hNoV) are the leading
cause for acute gastroenteritis across all age groups. In fact, a hypothetical vaccination
could save up to 2.1 billion dollars a year only in the United States.[1]
hNoV recognize histo blood group antigens (HBGAs) as cellular attachment factors.
Recently, it has been discovered that norovirus infection can be significantly enhanced by
HBGA binding.[2] Yet, the attachment process, and how it promotes host-cell entry is only
poorly understood. Here, we have studied binding of a norovirus protruding (P) domain of
a predominant GII.4 Saga strain to HBGAs at atomic resolution. So far, independent and
equivalent multiple binding sites were held responsible for attachment. Using NMR
experiments we show that norovirus-HBGA binding is a cooperative multi-step process,
and native mass spectrometry and crystallographic studies[3] reveal four instead of two
HBGA binding sites per P dimer, further supporting our findings.
The study of the topological features of HBGAs–hNoV interactions and protein dynamics
requires the assignment of NMR signals. As a complementary approach to classical 3D
NMR experiments, we envision to use paramagnetic effects (PRE and PCS)[4] transferred
from a paramagnetic HBGA into P dimers for helping in the assignment. Thus, L-fucose
covalently linked to a rigid lanthanide binding tag was synthesized and explored as a tool
for protein assignment.
[1] S. M. Ahmed, et al., Lancet Infect. Dis. (2014), 14, 725-730;
[2] L. Lindesmith, et al., Nat. Med. (2003), 9, 548-553.
[3] A. D. Koromyslova, et al., Virology (2015), 483, 203-208.
[4] G. Otting, Annu, Rev, Biophys. (2010), 39, 387-405.
153 Engineering Applications / Low Field NMR / Imaging
Multiple Applications of a Fully Thermostatted
Online NMR Probe for Reaction Monitoring and as
Detector for Reactive Chromatography
A. Brächer1, R. Behrens2, E. von Harbou3, H. Hasse4
Alexander Brächer, [email protected]
1-4 Laboratory of Engineering Thermodynamics, University of Kaiserslautern,
Germany
Using high-resolved online NMR spectroscopy for process and reaction monitoring
enables both qualitative and quantitative analysis of complex multicomponent
mixtures. The NMR probe employed for the monitoring has to meet certain
requirements: An efficient temperature management of the examined mixtures has to
be provided and the probe has to withstand industrially relevant pressures.
Furthermore, the feed tubes and the NMR flow cell itself have to be optimized to
avoid non-ideal flow characteristics, such as backmixing. In addition, the probe should
facilitate the investigation of processes that have short time constants, e.g. the kinetics
of fast chemical reactions.
To fulfill the requirements, a fully thermostatted flow probe was developed that can be
applied in a wide range of temperatures and pressures (-20 – 100 °C, up to 60 bar) [1].
In this work, multiple applications of the probe are presented that show the advantages
and the variability of the new design. The formation of poly(oxymethylmethylene)glycols by the reaction of acetaldehyde and water is one of the industrially
relevant systems that was investigated in this work. The reaction results in a complex
oligomeric species distribution that cannot be investigated with optical spectroscopy
methods. Kinetic measurements were carried out that enabled the development of a
new kinetic model [2]. To demonstrate the wide field of applications of the probe, the
product stream of a chromatographic fixed bed reactor was analyzed with this set-up
giving insight in the complex processes of the reactor.
[1] Brächer et al., J. Mag. Res., (2014), 242, 155-161
[2] Scheithauer et. al., Ind. Eng. Chem. Res., (2014), 53, 17589-17596
Magnetic resonance imaging (MRI) with atomic
resolution by NV sensors and ultra-strong
magnetic field gradients
A. Kleinkauf1, G. Braunbeck2, F. Reinhard3
Alexander Kleinkauf, [email protected]
1-3 Walter Schottky Institute, Department of Physics, Technical University Munich
The nitrogen-vacancy center, a colour defect in diamond, can serve as an atomic sized
quantum sensor for nanoscale magnetic fields. In recent years it has enabled both
nuclear magnetic resonance spectroscopy and electron spin resonance spectroscopy on
samples as small as a single bio-molecule [1-4].
We present our efforts to transform these results into a three-dimensional imaging
technique by combining the nitrogen-vacancy sensor with ultra-strong magnetic field
gradients. Specifically we present magnetic field simulations, which suggest that
gradients up to 108 T/m (103 G/nm) in the vicinity of the nitrogen-vacancy center can
be achieved by a nanostructure with spatial dimensions of 100 nm x 100 nm x 50 nm
and a saturation magnetization of 1 T. These parameters are well in reach of state of
the art nanofabrication technology such as thermally evaporated magnetic thin films
[5]. Magnetic resonance imaging in a magnetic gradient of this order of magnitude
could map nuclei with 20 kHz linewidth [1-3] with a spatial accuracy of 300 pm. This
paves the way for 3D imaging of single bio-molecules with atomic resolution.
[1] T. Staudacher et al., Science 339, 561 (2013)
[2] H.J. Mamin et al., Science 339, 563 (2013)
[3] D. Rugar et al., Nat Nano 10, 120–124 (2015)
[4] F. Shi et al., Science 347, 1135 (2015)
[5] D. Rugar et al. , Nature 430, 329-332 (2004)
Flow-MRI of microfluidic reactors
S. Benders1, M. Wiese2, S. Lehmkuhl3, E. Paciok4, M. Wessling5, B. Blümich6
Bernhard Blümich, [email protected]
1 Institut für Technische und Makromolekulare Chemie, RWTH Aachen University,
Germany
2, 5 Aachener Verfahrenstechnik, RWTH Aachen University
3, 4, 6 Institut für Technische und Makromolekulare Chemie, RWTH Aachen
University
In conventional reactors the surface-to-volume ratio limits the capability of
performing solid-state catalysis on the reactor walls. Microfluidic reactors improve the
ratio with their advantageous compact design [1] and are investigated utilizing flowMRI in this work.
The microfluidic reactor studied in this work has been 3D-printed with dimensions of
56x28x11 mm3 incorporating five channels (channel diameter approx. 0.848 mm).
The channels are sealed with an exchangeable glass plate suitable for catalyst
immobilization.
Velocity maps of water flowing through the reactor with 5 mL/h are presented. These
were measured with the flow-imaging employing single shot encoding (FLIESSEN)
sequence [2] in an AV300 magnet (Micro 2.5 gradient system, max. gradient strength:
1.57 T/m). The resolution is 130x90 μm2 with a Field-of-Flow of 20 mm/s and a slice
thickness of 3 mm. The observed velocity distributions in the channels are shaped
parabolic corresponding to laminar flow.
Moreover the velocity field in the channel cross section is measured utilizing the spin
echo velocity imaging (SEVELIM) sequence with a slice thickness of 7.5 mm
showing the distorted half-circular shape of the channels along with the distribution of
the z-velocities within those. The velocity is highest in the middle of the channel.
Comparing the ratio of maximum and mean velocities within each channel leads to a
ratio of 2.57±0.12, which is higher than the ratio of two for tubular flow in circular
geometry. In summary, the presented microfluidic reactor shows distorted laminar
flow.
[1] J. Kobayashi, Y. Mori, K. Okamoto, R. Akiyama, M. Ueno, T. Kitamori, S.
Kobayashi, Science (2004), 304 (5675), 1305-1308
[2] A. Amar, B. Blümich, F. Casanova, ChemPhysChem (2010), (11), 2630-2638
Applying MRI Techniques in IC-engine geometries
D. Freudenhammer1, R. Simpson2, B. Böhm3, C. Tropea4, S. Grundmann5
Daniel Freudenhammer, [email protected]
1, 4 Department of Fluid Mechanics and Aerodynamics, Technische Universität
2 Department of Radiology/Medical Physics, University Medical Center Freiburg,
Freiburg, Germany
3 Department of Reactive Flows and Diagnostics, Technische Universität Darmstadt,
Darmstadt, Germany
5 Department of Fluid Mechanics, University of Rostock, Rostock, Germany
Magnetic Resonance Velocimetry (MRV) was applied to acquire volumetric (3D3C)
intake flow velocity data for a modern engine geometry. MRV is especially beneficial
in this application because it resolves the volumetric flow within the complex internal
system of the intake port for which optical access is limited for traditional velocimetry
methods. The measurements were performed in an engine-equivalent polyamide
model with 1:1 scale geometry of a single-cylinder direct injection spark-ignition
optical engine [1].
Using MRV, zones of recirculating mass flow in the inlet port and around the
periphery of the valve curtain could be identified in 3D space. Reducing the effective
cross-sectional area for cylinder-filling, these recirculation zones may cause losses in
volumetric efficiency and possibly contribute to cyclic variations in IC engines. The
MRV measurements quantitatively resolved a highly uneven distribution of the mass
flow discharging into the cylinder through the valve curtain (annular area between the
valve head and valve seat) [2].
A new approach is the determination of turbulence quantities inside the engine model.
First measurements were conducted and need yet to be carefully validated using
traditional measurement techniques. First steps of this experimental approach and the
results achieved with MRV are content of the presentation.
[1] Baum E, Peterson B, Surmann C, Michaelis D, Böhm B, Dreizler A (2013)
Investigation of the 3D flow field in an IC engine using tomographic PIV. Proc
Combust Inst 34(2):2903–2910
[2] Freudenhammer D, Baum E, Peterson B, Böhm B, Jung B, Grundmann S (2014)
Volumetric intake flow measurements of an IC engine using Magnetic Resonance
Velocimetry. Experiments in Fluids 55(5):1724
Using MRI to Help Making Aircraft Engines Better
M. Bruschewski1, H.-P. Schiffer2, S. Grundmann3
Martin Bruschewski, [email protected]
1 Institute of Gas Turbines and Aerospace Propulsion, Technische Universität
2 Institute of Gas Turbines and Aerospace Propulsion, Technische Universität
3 Department of Fluid Mechanics, University of Rostock, Rostock, Germany.
Modern aircraft engines operate at temperatures well above the melting point of their
materials. A cooling system is required which usually features a combination of
internal cooling ducts and external cooling holes. A prediction of the cooling
effectiveness is difficult since the specific flow structure inside the cooling ducts is
usually unknown. Most cooling design are solely based on numerical simulations
rather than measurements. Funded by the DLR, the national aeronautics and space
research center of Germany, in cooperation with the aircraft engine manufacturer
Rolls-Royce Deutschland, this study has been conducted with the aim to investigate
whether MRI can be used to measure the flow field in such cooling ducts. The
presented work discusses the feasibility as well as the accuracy and uncertainty of
MRI. The investigated flow systems are generic and feature a strongly turbulent
swirling flow as a serious test case. The mean flow field is measured with a phasecontrast MRI sequence using water as flow medium while all important dimensionless
quantities are kept similar to the real application. The results are compared to state-ofthe-art laser measurements and sophisticated numerical simulations. As the main
outcome, it is shown that the measured flows are significantly different to what has
been predicted by conventional design tools. Furthermore, the measurements
generated a better understanding of the flow sensitivity and new design criteria could
be deducted. MRI has been proven a valuable supplement to existing tools in jet
engine research.
[1] Elkins C. and Alley M. (2007) Exp. Fluids 43(6):823–858.
[2] Grundmann, S., Wassermann, F., Lorenz, R., Jung, B., and Tropea, C. (2012)
Journal of Heat and Fluid Flow, 37:51–63.
[3] Bruschewski M., Scherhag C. Grundmann S. and Schiffer H.-P (2015) ASME
paper GT2015-42860.
158 EPR Methods
Electron Paramagnetic Resonance with Dielectric
Resonators of Small Single Crystals of MetalOrganic Frameworks
S. Friedlaender1, A. Kultaeva2, M. Simenas3, A. Poeppl4
Stefan Friedlaender, [email protected]
1-4 Fakultät für Physik und Geowissenschaften, Universität Leipzig, Germany
We will present our latest research on porous metal-organic framework (MOF)
compounds which offer a large application potential in various areas such as
adsorption, separation, catalysis, and sensing. While many of these materials contain
paramagnetic ions as major framework constituents, EPR investigations of MOF
systems are often restricted to powder materials because single crystals are only
available in sub-millimeter sizes. However, elucidation of the structure of the
adsorption complexes requires knowledge about the orientation of the magnetic
tensors which can only be deduced from single crystal experiments. We show that the
use of dielectric resonators with high permittivity enhances significantly the
sensitivity of the cw EPR experiment and in that way offers the opportunity for single
crystal studies of these porous, low density materials with very small volume samples
at low temperatures and non-ambient atmospheres in conventional cw EPR
spectrometers.[1] Here we will present our studies of Cu(II) containing small MOF
single crystals. In case of this structure containing Cu2-paddle wheel units as major
structural building units [2] we revealed the presence of mononuclear Cu2+ ion defect
species and explored their nature. We found that these paramagnetic defects are not
related to an impurity phase or extraframework species of the parent metal-organic
framework material but are formed within the framework at defective paddle wheel
units.
[1] Friedlaender, S., Ovchar, O., Voigt, H., Boettcher, R., Belous, A., and Poeppl, A.,
Appl. Magn. Res. (2015), 46 (1), 33.
[2] Simenas, M., Kobalz, M., Mendt, M., Eckold, P., Krautscheid, H., Banys, J., and
Poeppl, A., J. Phys. Chem. C (2015), 119, 4898.
159 EPR Methods
Room Temperature PELDOR Measurements with
Rigid Nitroxide Spin Labels on Duplex-DNA
M. Gränz1, D.B. Gophane2, S.Th. Sigurdsson3, T.F. Prisner4
Markus Gränz, [email protected]
1, 4 Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt,
Germany
2, 3 Science Institute, University of Iceland, Reykjavik, Iceland
Although pulsed EPR techniques, such as Pulsed Electron Electron Double Resonance
(PELDOR or DEER) provide highly accurate distance information in the nanometer
range and enable measurements of conformal changes even of flexible biomolecule
regions, these experiments are commonly carried out in frozen solutions at ~50 K.
Pushing this to a physiological temperature implies reducing the rotational correlation
time of the spins by decreasing the local and global motion. This has been
demonstrated by using trityl-labels with intrinsic slower relaxations rates attached to a
protein.[1] Immobilization of trityl-labeled DNA, bound to a surface, allowed
measurements of distances up to 4.6 nm.[2] More recently spirocyclohexyl-nitroxides
have been utilized to achieve distance informations by pulsed EPR at 295 K in a dry
glassy trehalose matrix.[3]
Here we present the first PELDOR data of nitroxides attached to DNA at room
temperature (RT), using rigid spin labels that have slow relaxation rates and distinct
distance distribution.[4] A number of rigid spin labled duplex DNAs, differing in their
label position, have been synthesized and immobilized using a rigid matrix. This
indeed resulted in a extended coherence time of the nitroxide spin labels, allowing
distance measurements at RT. When the spin-labeled duplex DNA was adsorbed to a
surface through electrostatic interactions, we were able to measure distances by
PELDOR even in liquid solutions. Thus offering a direct access to the time scale of
conformer dynamics.
[1] Yang, Z.; Liu, Y.; Borbat, P.; Zweier, J.; Freed, J.; J. Am. Chem. Soc. (2019) 134,
9950-9952
[2] Shevelev, G.; Krumkacheva, O.; Lomzov, A. [...] Bagryanskaya, E.; J. Am.
Chem. Soc. (2014) 136, 9874-9877
[3] Meyer, V.; Swanson, M.; Clouston, L.; Boratynski, P.; Stein, R.; Mchaourab, H.;
Rajca, A.; Eaton, S.; Eaton, G.; Biophy. J. (2015) 108, 1213-1219
[4] Marko, A.; Denysenkov, V.; Margraf, D.; Cekan, P.; Schiemann, O.; Sigurdsson,
S.; Prisner, T.; J. Am .Chem. Soc. (2011) 133, 13375-79
160 EPR Methods
Detection of Light-Induced Magnetization of
Pentacene in p-Terphenyl by Magnetic-Force
Microscopy
A.M. Rostas1, E. Schleicher2, S. Weber3, K. Kartaschew4, E. Brüdermann5,
M. Havenith6
Arpad Rostas, [email protected]
1-3 Institute for Physical Chemistry, University of Freiburg, Germany
4-6 Physical Chemistry II, Ruhr University Bochum, Germany
Magnetic-force microscopy (MFM) is widely used to detect weak magnetic forces
between a ferromagnetic tip and a magnetic sample [1].
In our cutting-edge approach we achieve a light-generated sample magnetization using
short-lived triplet states, which serve as paramagnetic probes. In order to do so, an
immobilized diamagnetic chromophore is photo-excited from its ground state (S = 0)
into its triplet state (S = 1). When detected on a time scale that is short with respect to
T1 spin-lattice relaxation, the strong non-Boltzmann population generated due to spinselective intersystem crossing can be exploited. For a statistical ensemble of triplet
states (with a 2-dimensional spatial ordering), this yields strong spin polarization even
at room temperature [2].
[1] U. Hartmann, Annu. Rev. Mater. Sci. 29, 53 (1999).
[2] N. M. Atherton, Principles of ESR, Ellis Horwood, (1993).
161 EPR Methods
Single Scan Cooperative Broadband Hahn
Echoes
W. Kallies1, S.J. Glaser2
Wolfgang Kallies, [email protected]
1, 2 Department of Chemistry, TU München
Rectangular pulses are the workhorse of magnetic resonance spectroscopy, however
their performance is experimentally limited. Optimal control theory provides tools to
improve pulse performance and robustness, tuning hundreds or thousands of pulse
parameters at feasible computational costs [1,2].
Concurrent optimization of pairs of pulses rather than individual pulses offers
significant gains in pulse performance over the latter as previously demonstrated for
Ramsey-type sequences consisting of two 90° pulses [3]. Here, it is shown that this
singel-scan cooperative (s2-COOP) pulse approach also yields significant
improvements for Hahn-type echoes, consisting of an excitation and a refocussing
pulse. In addition to the case of uncoupled spins, we also consider the case where
heteronuclear couplings or hyperfine couplings are present. Furthermore, in pulsed
EPR, the impulse response function of the apparatus is on similar timescale as the
pulse itself, leading to pulse distortions. This can be taken into account in pulse
optimizations [4] and improved algorithms for the compensation of such transient
effects will be discussed.
[1] N. Khaneja, T. Reiss, C. Kehlet, T. Schulte-Herbrüggen, S. J. Glaser, J. Magn.
Reson. (2005), 172, 296-305 .
[2] P. de Fouquieres, S. G. Schirmer, S. J. Glaser, I. Kuprov, J. Magn. Reson. (2011),
212, 412-417 .
[3] M. Braun, S. J. Glaser, New J. Phys. 16 (2014), 115002 .
[4] P. E. Spindler, Y. Zhang, B. Endeward, N. Gershenzon, T. E. Skinner , S. J.
Glaser, T. F. Prisner, J. Magn. Reson. (2012), 218, 49-58.
162 EPR Methods
Using Electrically Detected Magnetic Resonance
(EDMR) to characterize Defects on well-defined
Semiconductor Surfaces under Ultra-High
Vacuum conditions
H. Ronneburg1, T. Risse2
Hendrik Ronneburg, [email protected]
1 AG Risse, Institut für Physikalische und Theoretische Chemie, Freie Universität
Berlin
2 Institut für Physikalische und Theoretische Chemie, Freie Universität Berlin
Joint EPR Laboratory, Helmholtz-Zentrum Berlin & Freie Universität Berlin
The properties of surfaces and interfaces of solids play an important role for a variety
of technologically important fields ranging from semiconductor devices to
heterogeneous catalysis. The role of defects on these surfaces and interfaces is
particularly crucial to understand the properties of these systems. A major step is the
microscopic understanding of these properties, which is still challenging due to the
large complexity of most technologically used surfaces or interfaces and the lack of
appropriate methodology. To this end the investigation of model surfaces under welldefined ultrahigh vacuum conditions provides a possibility to address some of these
issues. EPR spectroscopy has proven to be a very versatile method to investigate
paramagnetic point defects on semiconductor surfaces and interfaces, however, the
conventional detection scheme suffers from insufficient sensitivity to cope with the
low defect density of high quality devices. However, electrically detected magnetic
resonance (EDMR) has shown to be able to overcome this sensitivity gap and was
used successfully in the past to characterize defects in semiconductor devices and in
particular at interfaces of such systems.
In this contribution we will present our current efforts to set up an EDMR experiment
working under ultra-high vacuum (UHV) conditions to investigate defects on
semiconductor surfaces. Recent advancements and challenges of a working set up as
well as first successful steps towards an investigation of single crystal silicon surfaces
will be discussed.
163 EPR Methods
Multifrequency CW/Pulsed EPR-Spectroscopy
Y. NejatyJahromy1, H. Alaei2, T. Hett3, E. Schubert4, D. Abdullin5, A. Berndhäuser6,
A. Meyer7, H. Matsuoka8, O. Schiemann9
Yaser NejatyJahromy, [email protected]
1-9 EPR Spectroscopy Group, Institute for Physical and Theoretical Chemistry,
University of Bonn
In the EPR service project Z1 of SFB 813 (Chemistry at Spin Centers), we utilize a
spectrum of EPR techniques to investigate a diverse set of spin centers.
Multifrequency continuous wave and/or pulse EPR spectroscopy is used to study the
geometric and electronic structure of spin centers, to follow the generation and
reaction pathways of paramagnetic species, and to probe the conformational dynamics
and magnetic interactions of spin bearing complexes. The experimentally determined
magnetic parameters are compared with corresponding values originating from
theoretical calculations. A handful of studied cases are presented.
164 EPR Methods
Pulsed EPR Dipolar Spectroscopy with High-Spin
Mn2+ Ions
D. Akhmetzyanov1, H.Y. Vincent Ching2, B. Endeward3, P. Demay-Drouhard4,
J. Plackmeyer5, V. Denysenkov6, S. Un7, H.C. Bertrand8, C. Policar9, T.F. Prisner10
Dmitry Akhmetzyanov, [email protected]
1, 3, 5, 6, 10 Institute of Physical and Theoretical Chemistry and Center for
Biomolecular Magnetic Resonance, Goethe University Frankfurt, Germany
2, 7 Institute for Integrative Biology of the Cell, Department of Biochemistry,
Biophysics and Structural Biology,Université Paris-Saclay,CEA,CNRS UMR 9198
4, 8, 9 Laboratoire des Biomolécules, Ecole Normale Supérieure-PSL Research
University, CNRS - UMR7203, UPMC, Paris, France
Pulsed EPR dipolar spectroscopy (PDS) [1] is a valuable tool for the precise
determination of nanometer scale distances between nitroxide spin probes that are sitespecifically attached into molecule of interest. Recently, high-spin Gd3+ and Mn2+
have been introduced as spin markers for proteins and nucleic acids [2,3]. Mn2+ is
especially interesting for biological applications, since numerous enzymes initially
contain it as a catalytic active centre. Moreover, due to similar properties, Mn2+ can
replace Mg2+, which is important for the tertiary structural fold of nucleic acids.
In this work two model compounds, containing Mn2+ dipolar-coupled with a nitroxide
and two coupled Mn2+, were investigated by PDS in order to understand the influence
of high-spin multiplicity of Mn2+ to the distance measurements. Pulsed electron
electron double resonance (PELDOR/DEER [1]) was performed on Mn2+ nitroxide
compound at Q- and G-bands [4]. Pronounced dipolar oscillation was observed at Qband detecting Mn2+ as well as nitroxide. Tikhonov regularisation gives the distances
that are in agreement with predictions. The G-band PELDOR time traces obtained by
pumping the nitroxide revealed orientation selection. PELDOR and relaxationinduced dipolar modulation enhancement (RIDME [5]) experiments were carried out
on coupled Mn2+ system. The determined distances are in agreement with the
predictions. The peculiarities due to the high-spin multiplicity of Mn2+ will be
discussed. Our results show, that Mn2+ is promising spin probe for distance
measurements in biological applications.
[1] A. Milov, et al., Sov.Phys.Solid State (1981),23,565-569.
[2] A. Potapov, et al., J.Am.Chem.Soc. (2010),132,9040-9048.
[3] D. Banerjee, et al., J.Phys.Chem.Lett. (2012),3,157-160.
[4] D. Akhmetzyanov, et al., Phys.Chem.Chem.Phys. (2015),17,6760-6766.
[5] L. Kulik, et al., Chem.Phys.Lett. (2001),343,315-324.
165 EPR Methods
Electrically detected electron paramagnetic
resonance by pulsed charge carrier extraction for
application in thin-film solar cell devices
A. Sperlich1, S. Väth2, A. Baumann3, V. Dyakonov4
Andreas Sperlich, [email protected]
1, 2 Experimental Physics VI, Julius Maximilian University of Würzburg, Würzburg,
Germany
3, 4 Bavarian Centre for Applied Energy Research (ZAE Bayern), Würzburg,
Germany
We developed a new detection scheme for electrically detected magnetic resonance
(EDMR) for a selective probing of photo-generated and extracted charge carriers in
opto-electronic and photovoltaic devices by means of pulsed, field-induced extraction
under EPR conditions. Our method determines quantitatively the impact of spindependent recombination on state-of-the-art thin-film organic solar cells (OSC).
Here we report first results on OSCs, produced from various solution processable
conjugated polymers and fullerene derivatives. We found, that the performance of
such devices is largely unaffected by spin-dependent processes on a quantitative level
– i.e. the influence on the photo current and hence the power conversion efficiency is
in the range of 10-4-10-5. This is surprising as there are numerous reports in literature
pointing out the significance of the role of spin in the functioning of organic
photovoltaics. We expect that, while spin-dependent processes are crucially involved
in the generation of photo-current from OSCs, charge recombination is not limited by
the spin state of involved charges.
166 EPR Methods
Synthesis and Application of Metal Complexes for
EPR-based Distance Measurement Techniques
J. Wegner1, M. Qi2, H. Hintz3, K. Keller4, M. Yulikov5, G. Jeschke6, A. Godt7
Julia Wegner, [email protected]
1-3, 7 Faculty for Chemistry and Center for Molecular Materials, Bielefeld University,
Bielefeld, Germany
4-6 Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland
Distance measurement by EPR spectroscopy is a very powerful tool to gain
information on structure and dynamics of (bio)macromolecules. Recently, the use of
Gd(III)-complexes as spin labels came into focus. [1] To evaluate their use and refine
the techniques, model systems of the type Gd-spacer-Gd-systems with Gd-PyMTA as
spin label and Gd-Gd-distances of 2 to 11 nm were prepared. With these rulers the
DEER technique [2] was evaluated and methods like RIDME [3] and population
transfer [4] were developed. Albeit Gd-PyMTA is suitable as the spin label there is
room for improvement, especially in terms of zero field splitting (ZFS). This, as well
as other important properties like relaxation times and echo reduction values depend
on the ligand and cannot be predicted. On our search for Gd-complexes with very
different ZFS values we synthesized a set of ligands and determined the EPR
properties of the corresponding Gd-complexes. The synthesis as well as the results of
the measurements and their implications on the use of the concrete Gd-complex as a
spin label for a specific technique will be presented in this contribution.
Besides Gd-complexes as spin labels, there is a huge interest in complexes of other
metal ions, like Cu(II), Co(II), Fe(III) and Mn(II), because of the request for
orthogonal spin labeling. Preliminary results on this topic will be presented.
[1] D. Goldfarb, Phys. Chem. Chem. Phys. (2014), 16 (21), 9685–9699.
[2] A, Dalaloyan, M. Qi, S. Ruthstein, S. Vega, A. Godt, A. Feintuch, and D.
Goldfarb, Phys. Chem. Chem. Phys. 2015, DOI: 10.1039/C5CP02602D.
[3] S. Razzaghi, M. Qi, A. I. Nalepa, A. Godt, G. Jeschke, A. Savitsky, and M.
Yulikov, J. Phys. Chem. Lett. (2014), 5 (22), 3970–3975.
[4] A. Doll, M. Qi, S. Pribitzer, N. Wili, M. Yulikov, A. Godt, and G. Jeschke, Phys.
Chem. Chem. Phys. (2015), 17 (11), 7334–7344.
167 EPR Methods
Pushing SIFTER towards new application
P. Schöps1, P.E. Spindler2, A. Bowen3, D. Akhmetzyanov4, T.F. Prisner5
Philipp Schöps, [email protected]
1-5 Institut für Physikalische und Theoretische Chemie und Zentrum für biologische
Magnetresonanz, Goethe Universität Frankfurt, Germany
SIFTER (single-frequency technique for refocusing dipolar couplings) [1] is one of
the forgotten pulsed EPR (electron paramagnetic resonance) techniques. It is possible
to achieve a higher signal to noise ratio for SIFTER compared to PELDOR (pulsed
electron electron double resonance, also called DEER) [2,3] and DQC (doublequantum coherence) [4]. However, drawbacks such as small modulation depths,
artifacts resulting from inefficient pulse inversion and an ambiguity in the definition
of the background function, have made previous SIFTER experiments ineffective.
Here we show that it is possible to overcome the first two drawbacks by utilizing
broadband pulses with nitroxide spin labels at X-band frequencies [5] or by using spin
labels with narrow spectral width, for example triarylmethyl based radicals (TAM or
trityl) [6]. The ambiguity in the definition of the background function is a general
problem for single frequency techniques and is our current subject of investigation
regarding SIFTER. Nevertheless in SIFTER the background can be minimized by
using small concentrations and broadband pulses leading to a large modulation depth.
The high excitation efficiency achievable with broadband-SIFTER for nitroxides at Xband frequencies, made it also possible to excite multi-spin effects in systems
consisting of more than two nitroxide radicals, which might be useful to determine
oligomeric states of proteins.
[1] G. Jeschke, M. Pannier, A. Godt and H. W. Spiess, Chem. Phys. Lett., 2000, 331,
243
[2] A. D Milov, K. M. Salikhov and M. D. Shchirov, Sov. Phys. Solid State 1981, 23,
565.
[3] M. Pannier, S. Veit, A. Godt, G. Jeschke and H. W. Spiess, J. Magn. Reson., 2000,
142, 331.
[4] P. P. Borbat and J. H. Freed, Chem. Phys. Lett., 1999, 313, 145
[5] P. Schöps, P. E. Spindler, A. Marko and T. F. Prisner, J.Magn. Reson., 2015, 250,
55
[6] T. J. Reddy, T. Iwama, H. J. Halpern and V. H. Rawal, J. Org. Chem., 2002, 67,
4635–4639
168 EPR Methods
ELDOR detected NMR of Manganese
coordination spheres at Q-band
T.F.B. Hetzke1, A.M. Bowen2, M. Vogel3, C. Grünewald4, T.F. Prisner5
Thilo Hetzke, [email protected]
1, 2, 5 Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt,
3 Department of Biology, Technische Universität Darmstadt, Darmstadt, Germany
4 Institute of Organic Chemistry and Chemical Biology, Goethe University Frankfurt
ELDOR detected NMR (EDNMR) is a method to probe hyperfine interactions.[1] In
contrast to ENDOR (Electron Nuclear Double Resonance), EDNMR uses a
microwave pulse with a variable frequency, ωELDOR, to transfer nuclear polarisation by
driving a forbidden transition. The nuclear polarisation transfer is observed as a
change in echo intensity for a Hahn echo sequence at a second, fixed microwave
frequency, ωdet. EDNMR is superior to ENDOR in terms of sensitivity and free of
typical ENDOR artefacts.
Most EDNMR studies have been performed at high magnetic fields (95 GHz). This is
due to the central blindspot, which arises in EDNMR spectra when ωELDOR,
approaches ωdet and therefore saturates the detected allowed EPR transition. The
central blindspot becomes particularly troublesome when detecting low-γ nuclei at
lower magnetic fields. Here, the signals, which are centred about their nuclear Larmor
frequencies, are frequently obscured by the central blindspot.
In this study we used EDNMR to detect 13C, 17O and 31P resonances of various Mn2+
complexes at Q-band (34 GHz). Initial results were collected on the [Mn(H217O)6]2+
model system. EDNMR was then used to study the interaction of 13C-tetracycline
(TC) and the TC-binding aptamer with Mn2+. Recent results reported at W-band (95
GHz) have shown the observation of natural abundance 13C and transitions involving
the simultaneous spin flip of two different nuclei.[2,3] Our results also show such
features and confirm the high sensitivity of EDNMR as a useful technique at the lower
frequency of Q-band.
[1] P. Schosseler, T. Wacker and A. Schweiger, Chem. Phys. Lett. (1994), 224 (3-4),
319-324
[2] E. M. Bruch, M. T. Warner, S. Thomine, L. C. Tabares and S. Un, J. Phys. Chem.
B (2015), ahead of print
[3] N. Cox, W. Lubitz and A. Savitsky, Mol. Phys. (2013), 111 (18-19), 2788-2808
169 EPR Methods
Time-resolved EPR studies of the hydroxyethyl
radical generated by the oxidation of ethanol with
the TiCl3/H2O2 system
E. Schubert1, T. Hett2, Y. NejatyJahromy3, O. Schiemann4
Erik Schubert, [email protected]
In the reaction of Fe(II) salts and H2O2 hydroxyl radicals are formed. These highly
reactive species can oxidise organic substances via abstraction of hydrogen radical
thus forming organic radicals. Analogously the so-called Fenton reaction can be also
carried out using Ti(III) as a low-valent metal and then is referred to as Fenton-like.
So far, numerous papers have been published examining the course of the reaction, its
intermediates and products as well as their decay.[1-9] The first reported EPR data of
radicals in solution formed by a Fenton-like system was published in 1963.[7]
Therein, the oxidation products of several alcohols were analysed, among those its
most popular representative, the hydroxyethyl radical formed from ethanol.
However, to the best of our knowledge, no kinetic studies of the decay of the
hydroxyethyl radical have been carried out so far using a continuous flow system in
conjunction with EPR spectroscopy. EPR spectroscopy is well suited for such cases
because it is a fast and sensitive method to detect radicals. Employing a dielectric
mixing resonator, in-situ generated radicals and their kinetics can be monitored
directly at room temperature and in solution.
Herein, we present a method to analyse the decay of the hydroxyethyl radical
produced from ethanol by the TiCl3/H2O2 system. For that purpose, kinetic data has
been acquired for reaction times in the millisecond range.
[1] Andersen et al., J. Agric. Food. Chem. 1998, 46, 1272–1275.
[2] Bielski et al., J. Phys. Chem. 1962, 66, 2266–2268.
[3] Buxton et al., J. Phys. Chem. Ref. Data 1988, 17, 513–886.
[4] Chiang et al., J. Phys. Chem. 1966, 70, 3509–3515.
[5] Czapski, J. Phys. Chem. 1971, 75, 2957–2967.
[6] Davies et al., J. Chem. Soc., Perkin Trans. 2 1992, 163–169.
[7] Dixon, et al., J. Chem. Soc. 1963, 3119–3124.
[8] Janata, J. Chem. Sci. 2002, 114, 731–737.
[9] Shiga, J. Phys. Chem. 1965, 69, 3805–3814.
170 EPR Methods
Investigating multi-spin nitroxide systems with a
broadband SIngle Frequency Technique for Refocusing
dipolar couplings (SIFTER) and Pulsed ELectron DOuble
Resonance (PELDOR).
A.M. Bowen1, P. Schöps2, P.E. Spindler3, J. Plackmeyer4, T.F. Prisner5
Alice Bowen, [email protected]
1-5 Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt,
Multispin systems, containing N>2 dipolar coupled nitroxide spins, can be difficult to
investigate using PELDOR.[1] This is a result of the PELDOR pulse sequence which
uses two frequencies to excite independently two coupled spins, thus the maximum
proportion of pairwise interactions that can be excited for a system with two coupled
nitroxides at X-band (9.5 GHz) using rectangular pulses is ca. 57%.[2] In multispin
systems this degree of excitation results in excitation of not only the pairwise
interactions, but also higher order multispin interactions. The multispin interactions
give rise to higher frequency components in the dipolar coupling spectrum, which,
after Tikhonov Regularization analysis, are seen as ghost peaks in the distance
distribution.
We show that it is possible to minimize the excitation of the multispin interactions
using PELDOR with a reduced pump pulse efficiency. In addition, we have used
SIFTER,[3] a single frequency technique, with broadband pulses (bandwidth ca. 200
MHz) that can excite the entire nitroxide spectrum at X-band.[4] This gives an
excitation efficiency of ca. 95% for a bi-radical model system and yields data for
multispin systems where the multispin interactions are the major component in the
dipolar spectrum. This is seen as a shift in the maximum of the resultant distance
distribution compared to that found using PELDOR on the same multispin system.
We present experimental data for tri- and tetra-radical systems that can be modelled
using simulations and propose how this technique could be used to probe aggregation
in samples.
[1] M. Pannier, et al., J. Magn. Reson. (2000), 142 (2), 331-340.
[2] T. von Hagens, et al., Phys. Chem. Chem. Phys. (2013), 15, 5854-5866.
[3] G. Jeschke, et al., Chem. Phys. Lett. (2000), 331, 243-252.
[4] P. Schöps, et al., J. Magn. Reson. (2015), 250, 55-62.
171 EPR Methods
Distances and Orientations with PELDOR/DEER
at High Fields/Frequencies
K. Halbmair1, I. Tkach2, M. Bennati3
Karin Halbmair, [email protected]
1-3 Research Group EPR Spectroscopy, Max Planck Institute for Biophysical
Chemistry, Göttingen , Germany
Low field (0.3 T/9 GHz) pulsed electron-electron double resonance (PELDOR/DEER)
is a widely used technique for distance measurements on biomacromolecules. At
higher fields and frequencies (35, 95 and 263 GHz), the method is affected by
orientation selectivity. This feature is usually considered as a nuisance that prevents an
accurate distance measurement. However, in many cases, high-frequency PELDOR
delivers information inaccessible at low fields. If distances are known, high-frequency
PELDOR permits to correlate the mutual orientation of paramagnetic centres [1,2].
Besides, the absolute sensitivity at high fields/frequencies is increased allowing
experiments on limited sample volumes.
However, at high frequencies, limited available power and increased microwave
losses render excitation pulses longer and therefore the signal weaker. This, combined
with a broader EPR spectrum of anisotropic centres, predicts weaker modulation
depths than those observed in X-band. Furthermore, the “out-of-phase” signal
observable at high fields [3,4] must be considered and adequately analysed.
Here, we present comparative high-frequency (35, 95 and 263 GHz) PELDOR studies
on model RNA systems containing rigid and flexible nitroxide spin labels and discuss
the advantages and possible bottlenecks of the high field measurements. We show that
at high fields/frequencies a considerable PELDOR modulation can be detected and
orientation selectivity is significant, which is particularly important for orientation
selective studies.
[1] V. P. Denysenkov et al, PNAS, (2006), 103(36), 13386–13390.
[2] I. Tkach et al, Phys. Chem. Chem. Phys., (2013), 15, 3433-3437
[3] A. Marko, et al (2013), 111(18-19), 2834-2844.
[4] I. Tkach et al, Appl. Magn. Reson., (2014), 45(10), 969-979.
172 EPR Methods
Broadband Electrically Detected Magnetic
Resonance Using Adiabatic Pulses
F.M. Hrubesch1, M.S. Brandt2
Florian Hrubesch, [email protected]
1-2 Walter Schottky Institut, Technische Universität München
We present a broad-band spin resonance setup with the ability to apply shaped pulses
for electrically detected magnetic resonance (EDMR). The setup uses non-resonant
stripline structures for on-chip radiofrequency and microwave delivery and was tested
to work in the frequency range from 4 MHz to 18 GHz. In combination with a
broadband microwave amplifier with a saturated power of 10 W the stripline
structures allow for B1 fields of 0.3 mT and higher. In the poster, we demonstrate the
functionality of this EDMR spectrometer using BIR4 pulses for arbitrary rotations of
both electron spins as well as nuclear spins in ENDOR experiments using adiabatic
pulses only [1]. Furthermore, we will outline possible further applications of the
broad-band capabilities of the system and report on the ongoing effort to employ
optimal control pulses.
[1] F.M. Hrubesch, G. Braunbeck, A. Voss, M. Stutzmann and M.S. Brandt, JMR
(2015), 254, 62-69.
173 EPR Methods
Pulsed EPR Dipolar Spectroscopy on a Trityl
Biradical
D. Akhmetzyanov1, P. Schöps2, A. Marko3, N. Kunjir4, S.Th. Sigurdsson5,
T.F. Prisner6
Dmitry Akhmetzyanov, [email protected]
1-3, 6 Institute of Physical and Theoretical Chemistry and Center for Biomolecular
Magnetic Resonance, Goethe University Frankfurt, Frankfurt/M, Germany
4, 5 Science Institute, Department of Chemistry, University of Iceland, Reykjavık
Pulsed EPR dipolar spectroscopy [1-3] is a valuable technique for the precise
determination of nanometer scale distances between paramagnetic centres. Nitroxide
spin species attached by site-specific spin labelling are mostly used for this kind of
measurements. Recently, another type of organic radicals, triarylmethyl (trityl) has
been used as alternative spin marker for dipolar spectroscopy. These paramagnetic
centres exhibit longer electron spin relaxation times and reveal higher stability toward
redox processes under in-vivo conditions compared to nitroxides.
In this work we studied a trityl biradical by dipolar spectroscopy at Q - (33.8 GHz)
and G - (180 GHz) band frequencies. The trityl EPR spectrum obtained at Q-band
frequencies revealed a narrow spectral width of about 30 MHz. Hence, the usage of
single-frequency dipolar spectroscopy techniques is beneficial. SIFTER [2] and DQC
[3] experiments were carried out and the performance of these experiments was
compared with each other. The distances extracted from the dipolar evolution
functions using Tikhonov regularisation are in agreement with literature [4]. The trityl
EPR spectrum obtained at G-band frequencies revealed an axial symmetric anisotropy
of the g-tensor and a spectral width of about 160 MHz. This allowed the performance
of PELDOR [1] experiments with high sensitivity. The time traces obtained at
different pump-probe positions across the EPR spectrum exhibited orientation
selection. By using a fit algorithm [5], additionally to the distance, information about
the flexibility of the molecule was extracted.
[1] A. Milov, K. Salikhov, M. Shchirov, Sov. Phys. Solid State (1981), 23, 565-569.
[2] G. Jeschke, M. Pannier, A. Godt, H. W. Spiess, Chem. Phys. Lett. (2000), 331,
243-252.
[3] P. Borbat, J. Freed, Chem. Phys. Lett. 1999, 313, 145-154.
[4] G. Reginsson, N. Kunjir, S. Sigurdsson, O. Schiemann, Chem.-Eur. J. (2012), 18,
13580-13584.
[5] A. Marko, T. Prisner, Phys. Chem. Chem. Phys. 2013, 15, 619-627.
174 EPR Methods
Improving the Detection Limit of Quantitative EPR
on Si Dangling Bond Defects by Rapid Scan EPR
J. Möser1, A. Schnegg2, K. Lips3, B. Rech4
Jannik Möser, [email protected]
1-3 Institute for Nanospectroscopy, Helmholtz-Zentrum Berlin for Materials and
Energy, Berlin, Germany
4 Institute for Silicon Photovoltaics, Helmholtz-Zentrum Berlin for Materials and
Energy, Berlin, Germany
A major issue impeding the progress of photovoltaics remains the price relationship
compared to conventional carbon-based energy sources. Increasing effort has been put
into the development of thin-film silicon (TFS) solar cell devices in order to reduce
material costs. However, the conversion efficiency of TFS based devices suffer from
electronic defects, which act as recombination centers for charge carriers and thus
limit the electronic transport in the cell. A prominent example of such a defect is the
dangling bond (DB), a three-fold coordinated silicon atom with one electron being left
unpaired. As DBs are paramagnetic, EPR is the tool of choice for analyzing and
quantifying these electronic defects. Nevertheless, considering the enhanced electronic
quality of state-of-the-art TFS materials, defect densities approach the detection limit
of continuous wave EPR (cwEPR).
We recently managed to push this limit for the detection of DBs in TFS materials by
employing rapid scan EPR (rsEPR). For DBs in hydrogenated amorphous silicon
(a-Si:H), we found that rsEPR allows for S/N improvements of up to a factor of 90 as
compared to conventional cwEPR. These rsEPR experiments were carried out on a
commercial Bruker pulse EPR spectrometer, without the need for any hardware
changes. Furthermore, we have been working on transferring quantitative EPR
methods from cw to rsEPR, for the determination of dangling bond defect densities
with improved sensitivity. Herein, we present recent quantitative rsEPR results
obtained on TFS materials with varying morphologies and defect densities.
175 EPR Methods
Imaging few spins under ambient conditions
T. Oeckinghaus1, A. Zappe2, D. Dasari3, K. Bader4, P. Neumann5, A. Finkler6,
J. Wrachtrup7
Thomas Oeckinghaus, [email protected]
1-3, 5-7 3rd Physics Institute, University of Stuttgart, Germany.
4 Institute of Physical Chemistry, University of Stuttgart
Magnetic resonance is an essential tool for analyzing the structure and dynamics of
biomolecules. However, common magnetic resonance methods require averaging over
a large ensemble of spins. Using a single nitrogen-vacancy center in diamond as an
atom-sized sensor enables the detection of nanoscopic nuclear spin ensembles or few
electron spins under ambient conditions [1, 2]. By scanning a magnetic field gradient
over the sample, a high spatial resolution of the spin density can be achieved.
Combining this scheme with site-specific spin labeling of proteins could lead to a
powerful method for revealing the structure and dynamics of single molecules or
proteins.
[1] T. Staudacher, F. Shi, S. Pezzagna, J. Meijer, J. Du, C. A. Meriles, F. Reinhard,
and J. Wrachtrup, Science (2013), 339 (6119), 561-563.
[2] F. Shi, Q. Zhang, P. Wang, H. Sun, J. Wang, X. Rong, M. Chen, C. Ju, F.
Reinhard, H. Chen, J. Wrachtrup, J. Wang, and J. Du, Science (2015), 347 (6226),
1135-1138
176 EPR Methods
New nitroxide and gadolinium spin labels to probe
conformational changes of Bcl-2 proteins on
isolated mitochondria
T. Assafa1, S. Bleicken2, A.J. García-Sáez3, M. Qi4, A. Godt5, H. Zhang6, A. Rajca7,
E. Bordignon8
Tufa Assafa, [email protected]
1, 8 Berlin Joint EPR Laboratories, Department of Experimental Physics, Free
University of Berlin
2, 3 Interfaculty Institute of Biochemistry, Eberhard Karls University Tübingen
4, 5 Faculty of Chemistry and Center for Molecular Materials, Bielefeld University
6, 7 Department of Chemistry, University of Nebraska, USA
Efforts have been made to test the compatibility of spectroscopically distinct spin
labels for orthogonal labelling of multiple Bcl-2 proteins in-organello. Mitochondria
were isolat-ed from Sprague Dawley rat liver for initial tests with gadolinium and
nitroxide spin probes. DEER experiments were conducted on the biradical form of a
new gadolinium chelator, PyMTA [1], to see if the chelator could resist
transmetallation during mito-chondrial lysis or high temperature. A Gd(III)-4-vinylPyMTA spin label [1] was tested for its reactivity towards cysteines but it was found
that the labelling efficiency was too low to spin label the protein model system T4
lysozyme using standard conditions, therefore an optimized Gd(III)-PyMTA spin label
with higher reactivity is under devel-opment. Cw-EPR time-resolved experiments on
mitochondria have been used to ob-serve how different types of nitroxide probes are
reduced during lysis. The most suita-ble spin label gem-diethyl-pyrolline [2] was
synthesized with the maleimide reactive group and successfully used to label the proapoptotic human protein Bax. Time-resolved experiments were performed to follow
the insertion of the newly spin-labeled Bax into liposomes and isolated mitochondria
from rat liver. First DEER experiments on active spin-labeled Bax are presented and
compared with previous studies using con-ventional MTSL [3].
[1] M. Qi, A. Groß, G. Jeschke, A. Godt, M. Drescher, J Am Chem Soc (2014), 136,
15366-15378.
[2] Y. Wang, J. T. Paletta, K. Berg, E. Reinhart, S. Rajca, A. Rajca, Org Lett (2014),
16. 5298-5300.
[3] S. Bleicken, G. Jeschke, C. Stegmueller, R. Salvador-Gallego, A. J. García-Sáez,
E. Bordignon, Mol Cell (2014), 56, 496-505.
177 Hyperpolarization
Studying the porosity of MOFs using 129Xe NMR
with hyperpolarized Xe
T.W. Kemnitzer1, Y.A. Avadhut2, E.A. Rößler3, J. Senker4
Tobias Willi Kemnitzer, [email protected]
1, 2, 4 Inorganic Chemistry III, University of Bayreuth, Bayreuth, Germany
3 Experimental Physics II, University of Bayreuth
Metal organic frameworks are showing an increasing relevance in modern
applications due to their functionality in combination with high surface areas [1].
Applications are ranging from gas separation and storage to catalytic applications.
Since pore size and shape is an important property the study of porosity of these
materials has to be examined closely. 129Xe NMR spectroscopy is a valuable tool to
get information about the pore shape, size and even adsorption dynamics.
We are able to increase the nuclear polarization of 129Xe by four orders of magnitude.
This allows us to detect adsorbed Xenon atoms even below the detection limits of
conventional gas physisorption [2].
For determination of pore sizes by 129Xe-NMR the model published from Fraissard [3]
is the most prominent one. But this model reaches its limits for MOFs. This could be
due to different interactions of the organic linker molecules with adsorbed Xe gas or
an electric field caused by the existing metal clusters inside of the network. In order to
determine which properties cause an influence on the chemical shift we correlate
129
Xe shifts with several types of MOFs. The influence of the pore size is studied by
changing them via the use of isoreticular structures or postsynthetic modification of
functional groups. Also the effect of electric fields is investigated by comparing
MOFs possessing differently charged metal centers. By combining these results and
supporting them with pore size distributions obtained from physisorption isotherms
new models to describe pore sizes will be developed.
[1] G. Férey, Chem. Soc. Rev. (2007), 37, 191-214.
[2] P. Ruckdeschel, T. W. Kemnitzer, F. A. Nutz, J. Senker, M. Retsch, Nanoscale
(2015), 7, 10059-10070.
[3] J. Demarquay, J. Fraissard, Chemical Physics Letters (1987), 136, 314-318.
Gd(III) DOTA as polarizing agent at high field:
Solid Effect vs Cross Effect Dynamic Nuclear
Polarization
M. Kaushik1, D. Richter2, B. Corzilius3
Monu Kaushik, [email protected]
1-3 Institute for Physical and Theoretical Chemistry, Center for Biomolecular
Magnetic Resonance (BMRZ), Goethe University Frankfurt, Frankfurt, Germany
Over the years, a wide variety of radicals have been tested and used as polarizing
agents in DNP NMR. Generally, radicals embedded in glass forming matrix act as the
source of electron polarization. Organic radicals such as TOTAPOL, AMUPol, trityl,
or BDPA are widely used for DNP. However, for specific applications, paramagnetic
metal ions prove to be an advantageous choice. Many metalloproteins contain
paramagnetic metals or can easily be doped with a paramagnetic substitute. Along
with acting as an efficient polarizing agent, transition metal ions serve as an excellent
model for studying polarization transfer mechanisms/pathways. Transition metal ions
like Gd3+(S = 7/2), Mn2+(S = 5/2) are known to give rise to 1H solid effect (SE) DNP
owing to their narrow EPR resonance. Here, we present the SE enhancement of nuclei
with low gyromagnetic ratio via Gd3+, including the first observation of resolved 15N
SE. Furthermore, an interesting interplay of competing cross effect (CE) is inspected
for such notably narrow (~14 MHz at 263 GHz) linewidth species. So far, the CE
polarization transfer mechanism is mainly attributed to radicals with a sufficiently
broad EPR line such as TOTAPOL (~1200 MHz at 263 GHz). The contribution of
each polarization transfer mechanism is investigated for different concentrations of the
Gd3+ polarizing agent. This study gives an insight into theoretical and experimental
aspects of high field DNP with high-spin transition metal ions.
Investigation of proteins with endogenously bound
Gd3+ for dynamic nuclear polarization (DNP)
D. Richter1, M. Kaushik2, D. Wagner3, H. Schwalbe4, B. Corzilius5
Diane Richter, [email protected]
1, 2, 5 Institute of Physical Chemistry and Center for Biomolecular Magnetic
Resonance(BMRZ), Goethe University Frankfurt, Frankfurt/M, Germany
3, 4 Institute of Organic Chemistry and Center for Biomolecular Magnetic Resonance
(BMRZ), Goethe University Frankfurt
Many biomolecules already contain a paramagnetic metal ion or a diamagnetic ion can
be easily substituted by a paramagnetic analog. Alternatively proteins can be
functionalized covalently or non-covalently with a paramagnetic species which can
then be utilized as endogenous polarizing agents[1]. At the same time it would be
possible to evoke a site-specific direct polarization of nuclei in the vicinity of the
paramagnetic site. This site-specific enhanced nuclear polarization would not only
counteract signal losses by paramagnetic relaxation, but would also allow for the
extraction of structural constraints[2].
DNP using Gd3+ as polarizing agent has already been shown to provide significant
DNP enhancement[3]. Here we introduce one possible target for bio-intramolecular
DNP: an engineered protein containing a lanthanide-binding tag (IL-1b-R2-LBT)[4].
We determined the linewidth and the relaxation times of the central (ms = ‒ ½  + ½)
EPR transition using pulsed EPR at Q-band (34 GHz) as well as G-band (180 GHz)
frequencies and show that these parameters can be directly related to the magnitude of
the DNP enhancement. Furthermore, we performed indirect (1H) and direct (13C) DNP
experiments on the uniformly [13C,15N]-labeled IL-1b-R2-LBT with Gd3+ and Lu3+
using bis-nitroxides as polarizing agents at 9.4 T (263GHz/400 MHz). During direct
(13C) DNP the NMR signal shows a distinct spectrally selective inversion and
enhancement in all samples. However, the presence of Gd3+ leads to a stark
amplification of this inversion possibly due to DNP-induced nuclear Overhauser
effect.
[1] Maly T. et al., J. Phys. Chem. B 2012, 116, 7055-7065
[2] van der Cruijsen et al., Chem. Eur. J. 2015, in press
[3] Corzilius B. et al., J. Am. Chem. Soc. 2011, 133, 5648-5651
[4] Barthelmes et al., J. Am. Chem. Soc. 2011, 133, 808-819
180 Poster Presentation P77
High spectral resolution 1H, 13C DNP probehead
for liquids at 9.4 T
V. Denysenkov1, T.F. Prisner2
Vasyl Denysenkov, [email protected]
1, 2 Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt,
Recently achieved DNP enhancements in liquids at high magnetic fields [1-3] have
initiated strong interest in possible applications of the method to biomolecular
research [4]. However, spectral resolution of available DNP probes was strongly
limited due to the complicated geometry mostly determined by microwave
components involved in the design of the probes, as well as by the sample orientation
[5]. Together with a low RF filling factor this resulted in a small overall NMR signal
amplitude, hampering sensitive observation of biomolecules. Here we present first test
results of the dual (1H; 13C) probe for liquid-state DNP as a combination of the
semiconfocal Fabry-Perot resonator with a stretched elliptical mirror for microwave
excitation at 260 GHz and the coplanar line for NMR excitation / detection at 400
MHz that offers 1) improved spectral resolution (5 Hz 1H NMR line in water), 2)
microfluidic sample handling with a typical sample volume of 100 nl, 3) active sample
cooling by water. First DNP test results promise significantly improved NMR
performance with respect to the 9.2 T DNP probes designed previously.
[1] Denysenkov V., Prandolini M., Gafurov M., Sezer D., Endeward B., Prisner T.,
PCCP (2010), 12, 125786-5790.
[2] Türke M.-T., Tkach I., Höfer P., Bennati M., PCCP (2010), 12, 5893-5901.
[3] Vilanueva-Garibay J., Annino G., van Bentum J., Kentgens A., PCCP (2010),12,
5846-5849.
[4] Jakdetchai O., Denysenkov V., Baldus J., Prisner T., Glaubitz C., JACS (2014),
136, 15533-15536.
[5] Denysenkov V., Prisner T., JMR (2012), 217, 1-5.
Parahydrogen Induced Polarization (PHIP) of
anticancer drug substructures
M. Plaumann1, D. Lego2, T. Trantzschel3, J. Wüstemann4, G. Sauer5, T. Gutmann6, G.
Buntkowsky7, J. Bargon8, U. Bommerich9, J. Bernarding10
Markus Plaumann, [email protected]
1, 3, 4, 9, 10 IBMI, Otto von Guericke University Magdeburg, Germany
2 Leibniz Institute for Neurobiology, Magdeburg
3 IBMI, Otto-von-Guericke-University, Leipziger Str. 44, 39120 Magdeburg
5-7 Institute for Inorganic & Physical Chemistry, Technische Universität Darmstadt,
Germany
8 Institute of Physical and Theoretical Chemistry, University of Bonn, Germany
A key challenge in the treatment of cancer is the in vivo tumor detection, in particular
of small pathological tissue changes. But MRI, being an important tool, still suffers
from low sensitivity. The SNR of potential new contrast agents can be increased by
using hyperpolarization methods such as PHIP[1]. The use of anti-cancer drugs itself
as marker molecules to detect the in vivo distribution as well as the tumor and
potential metastases is an advantageous concept.
Several of these drugs, e.g. Lapatinib, contain 19F, characterized by a complete lack of
background signals. Therefore, they qualify as new contrast agents for 19F MR in
combination with PHIP. Hence, we chose a structurally related molecule, 2-(3fluorophenyl)-3-butyn-2-ol, as an exemplary precursor. Hyperpolarization was
realized by p-H2 transfer in Earth´s magnetic field and subsequent transport into high
field (BRUKER WB-300). As expected, the strongest PHIP signals were observed for
1
H, 13C and 19F in organic solvents. In comparison to former studies[2,3], the current
substrate has a higher water solubility which is a prerequisite for the in vivo
application. Despite of low reaction rates, due to the decreased hydrogen solubility,
notable 1H PHIP signals from the product could be detected. This indicates, that for
this and related structures, sufficient polarizations might also be generated for 13C and
19
F in D2O using optimized reaction conditions in combination with field cycling[2] or
special pulse sequences[4].
[1] Natterer J. et al., Prog. Nucl. Magn. Reson. Sp. (1997), 31, 293-315.
[2] Bommerich U. et al., Phys. Chem. Chem. Phys. (2010), 12, 10309–10312
[3] Plaumann M. et al., Proc. Intl. Soc. Mag. Reson. Med. (2014), 22, 2780.
[4] Goldman M. et al., C. R. Physique (2005), 6 (4-5), 575–581.
DNP Enhanced ssNMR Study of the Interaction of
an Engineered Binding Protein with alphasynuclein Fibrils
B. Uluca1, H. Shaykhalishahi2, W. Hoyer3, H. Heise4
Boran Uluca, [email protected]
1-4 Institute of Complex Systems-6, Forschungszentrum Jülich, Germany
Most neurodegenerative diseases are associated with protein aggregation and
misfolding. α-synuclein (AS) is an abundant brain protein of 140 residues, and
accumulation of AS is a hallmark of Parkinson´s disease (PD) [1]. One promising
approach to prevent proteins from aggregating is their solubilisation by engineered
binding proteins which sequester the hydrophobic core region. The β-wrapin AS69[2]
,is a small binding protein with high affinity for AS. It does not only keep the
monomers in solution but it has also been found to bind to mature fibrils and partially
solubilize them.
We have investigated the binding of AS69 to AS fibrils by solid-state NMR
spectroscopy. DNP signal enhancement yielded signal enhancements of at least 30,
and was crucial for the observation of the bound AS69. Low temperature studies
allowed for a quantification of folded vs unfolded regions of AS from different wellresolved cross peak patterns.
Sparse selective labelling with different 13C labelling schemes for both molecules [3]
was employed to probe intermolecular interactions and allowed for obtaining selected
peak patterns in higher resolution. We demonstrate the high sensitivity and spectral
resolution obtained with this specific 13C labelling protocol for fibrillar sample in
comparison with fully 13C labelled samples.
[1] Cookson MR. The biochemistry of Parkinson's disease. Annual review of
biochemistry 2005;74:29-52.
[2] Mirecka EA, Shaykhalishahi H, Gauhar A, Akgul S, Lecher J, Willbold D, et al.
Sequestration of a beta-hairpin for control of alpha-synuclein aggregation.
Angewandte Chemie 2014;53:4227-30.
[3] Hong M, Jakes K. Selective and extensive 13C labeling of a membrane protein for
solid-state NMR investigations. J Biomol NMR 1999;14:71-4.
183 Materials in solid state NMR/EPR
Solid state NMR, diffraction and modeling of
intermetallics
F. Haarmann
Frank Haarmann, [email protected]
Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074
Aachen, Germany
Intermetallic compounds are a fascinating class of materials with respect to structural
chemistry and technological applications. The interest of basic research focuses on
chemical bonding and local ordering of the atoms.
Combined application of NMR, quantum mechanical calculations of NMR parameters
on DFT level, and X-ray diffraction was applied to study the peculiarities of the Ga
bonding situation in alkaline earth metal gallides [1,2]. The compounds were chosen
as a model system to derive reliable NMR parameters for the investigation of
intermetallic compounds possessing metallic conductivity.
The electric field gradient (EFG) turned out to be the desired quantity since very good
agreement of calculations and experiments were achieved. An analysis the EFG
reveals its local character being determined by the population difference of the Ga
electron p-states.
Due to the reliability of the EFG for the investigation of intermetallic compounds the
influence of disorder on the local Ga bonding situation was studied in the solid
solution of Sr1-xBaxGa2.
Super lattice structures were derived to model the varying local atomic arrangements.
DFT calculations based on these super lattice models enable an estimation of the EFG
being in good agreement with the experiment. Thus, the EFG can also be used to
study local atomic arrangements in disordered metallic materials.
The anisotropic conductivity of the powder samples was used to align the crystallites
in the magnetic field resulting in an increased experimental resolution [3,4].
[1] F. Haarmann, K. Koch, D. Grüner, W. Schnelle, O. Pecher, R. Cardoso-Gil, H.
Borrmann, H. Rosner, and Yu. Grin, Chem. Eur. J. 2009, 15(7), 1673 – 1684.
[2] F. Haarmann, K. Koch, P. Jeglič, O. Pecher, H. Rosner, and Yu. Grin, Chem. Eur.
J. 2011, 17(27), 7560 – 7568.
[3] O. Pecher, F. Haarmann, Nachrichten aus der Chemie 2013, 61(10), 1017-1021.
[4] F. Haarmann, In R. K. Harris, R. E. Wasylishen, Editors, Enzyclopedia of
Magnetic Resonance, John Wiley & Sons, Ltd, Chichester 2011.
Expanding the NMR Palette: Insights on Artificial
Charge Separators
B. Thomas1, M. Clabbers2, K.B.S.S. Gupta3, R.K. Dubey4, J. Rombouts5, W.F. Jager6,
U. Baumeister7, R. Orru8, J.P. Abrahams9, H.J.M. de Groot10
Brijith Thomas, [email protected]
1-3, 9, 10 Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
4, 6 Delft Univeristy of Technology, Delft, Netherlands
5 Vrije Universiteit Amsterdam, Netherlands
7 Martin-Luther-Universitat Halle-Wittenberg, Muhlpforte 1, 06108 Halle, Germany.
8 Department of Chemistry, Vrije Universiteit Amsterdam
Spurred by worries over climate change, there is increasing interest in mimicking
natural photosynthesis for the conversion of solar energy into fuel. The molecular
structure and packing of self-assembled Zinc Salphen/NDI dyad and Perylene-based
molecules, which are potential charge separators were studied in detail in the solid
state.
The combination of MAS NMR, TEM, Powder XRD and molecular modeling provide
a powerful methodology to investigate molecular geometry (and properties) of larger
unlabeled - aggregated supramolecular systems. DFT calculations were performed
using the CASTEP module in the material studio with GIPAW wave function.
Quantum mechanical calculations allow experimental 1H and 13C solid-state NMR
spectra to be assigned in a quantitative manner to a specific molecular packing
arrangement, starting from the chemical structure of a moderately sized molecule. The
incompleteness of NMR data is supplemented by data from TEM and powder XRD.
Here we simulated the distance constraints obtained from the LGCP build up curve
using Simpson/Spinevolution for the selected carbon atoms. An electron density map
of the proposed structure is generated and it’s projected down, followed by Fourier
transform using EMAN2 software to simulate the electron diffraction pattern. We
described a methodology in which the computational integration of MicroED, Powder
XRD and SSNMR (SMARTER Crystallography) to propose a model for a molecule
with high molecular weight. This methodology could be extended to understand the
mechanism of battery in the near future.
[1] Ganapathy S, et al., PNAS. (2009),11472-11477.
[2] Miller NC, et al. Adv. Mater. (2012), 24, 6071-6079.
[3] Baias M, et al. JACS. (2013), 135, 17501-17507.
Mechanochemical Synthesis of Low-Fluorine
doped Aluminium Hydroxide Fluorides
V. Scalise1, G. Scholz2, E. Kemnitz3
Gudrun Scholz, [email protected]
1-3 Department of Chemistry, Humboldt University of Berlin, Germany
Simultaneously present Lewis-acid and Brønsted-acid sites make aluminium
hydroxide fluorides very interesting for many different applications especially in the
field of catalysis. The successful mechanochemical synthesis of nanocrystalline
aluminium hydroxide fluoride samples AlFx(OH)3-x-nH2O with pyrochlor structure
was previously shown in our group [1]. Optimal conditions for the synthesis were
achieved using γ-Al(OH)3 and β-AlF3-3H2O as educts with a molar ratio Al:F of
1:1.5. Starting from the same reference system, we reduced the amount of F from
1:1.5 to 1:0.05 in order to produce highly distorted oxide/hydroxide fluorides. A
simple milling process of these educts, without additional post-treatment of the
products, was done. The impact of the F-doping by milling on local structures of
aluminium and fluorine and resulting consequences for the behaviour of these systems
in water, was the main intention of this research work. The unmilled and milled educts
along with resulting products obtained by milling were characterized by XRD, MAS
NMR (19F and 27Al), FT-IR and zeta-potential measurements. The 27Al MAS-NMR
spectra show how even the lowest F-doping is able to increase the amount of the AlX4
and AlX5 species (X:OH,F). A comparison of the chemical shifts observed for fluorine
and aluminum depending on the F-content with chemical shift trend analyses
previously published [2,3], allowed an assignment of the observed local coordinations
[4].
[1] G.Scholz, S. Brehme, M. Balski, R. König, E.Kemnitz, Solid State Sciences 2010,
12, 1500-1506.
[2] R. König, G. Scholz, R. Bertram, E. Kemnitz, J. Fluorine Chem. 2008, 129, 598606.
[3] R.König, G.Scholz, A. Pawlik, C. Jäger, B.v. Rossum, H. Oschkinat, E.Kemnitz,
J. Phys. Chem.C 2008, 112, 15708-15720.
[4] R.König, G.Scholz, A. Pawlik, C. Jäger, B.v. Rossum, E. Kemnitz, J. Phys.
Chem.C 2009, 113, 15576-l5585.
NMR investigations of segmental dynamics in
self-healing elastomers
A. Mordvinkin1, K. Saalwächter2, M. Suckow3, F. Böhme4
Anton Mordvinkin, [email protected]
1, 2 Institute of Physics - NMR Group, Faculty of Natural Sciences II, Martin-LutherUniversität Halle-Wittenberg
3, 4 Leibniz-Institut für Polymerforschung Dresden e.V.
Often self-healing properties, i.e. macroscopic damage recovery, manifest themselves
in supramolecular elastomers due to the dynamic nature of supramolecular bonds.
Thus, the self-healing ability is defined on a microscale and can be described by the
microscopic quantity called the supramolecular bond lifetime τb. The access to τb is a
key moment in understanding of their self-healing ability on a macroscale. This can be
addressed by means of multiple-quantum (MQ) NMR [1] which has already proved
itself to be a powerful and reliable tool to probe the segmental dynamics of polymeric
systems. MQ NMR gives insights into changes in orientational correlations of
monomeric segments with time and hence can provide the useful information
concerning the time scale on which a supramolecular network disappears. The objects
of investigation are poly(isobutylene)-based rubbers laterally modified as well as endfunctionalized with ionic-liquids or hydrogen-bond-donating moieties which exhibit
self-healing properties by formation of ionic clusters [2] or hydrogen bonds [3]
respectively. The focus of the project was set on finding quantitative relationships
between microscopic properties, particularly the supramolecular bond lifetime τb, and
macroscopic properties. For this, NMR studies are complemented by rheological
investigations.
[1] K. Saalwächter, Prog. NMR Spectrosc., 51, 1-35, 2007.
[2] M.A. Malmierca, et al., Macromolecules, 47, 5655-5667, 2014.
[3] F. Herbst, et al., Macromolecules, 43, 10006-10016, 2010.
Redistribution of magnetization after T2-filtered
experiments in linear polymer melts
M.-L. Trutschel1, K. Saalwächter2
Marie-Luise Trutschel, [email protected]
1, 2 FG NMR, Institut für Physik, Martin-Luther-Universität Halle-Wittenberg,
Germany
Results of pulsed field gradient (PFG) NMR measurements of diffusion of polymers
are usually corrected on the basis of model assumptions concerning the polydispersity
[1], based on the notion that higher molecular weights (MW) have shorter T2, being
thus underrepresented after the pulse sequence. On the other hand, the transverse
relaxation of polymers is known to be intrinsically non-exponential and to correspond
to a superposition of decays associated with the chain center and its termini [2]. This
effect may well dominate over the MW-related bias effect, and thus warrants closer
inspection.
In our study, we focus on selection effects of the magnetisation along the chain of
poly(butadiene). We measured T2-filtered Hahn echo decays of monodisperse samples
with various z-filter mixing times in an exchange-type experiment (where T1 limits the
mixing time). Due to the T2-filter the initial Hahn echo decay is dominated by longer
T2 components representing chain-end signals. The longer the mixing time, the more
similar again to the unfiltered Hahn echo the decay becomes. We evaluate whether the
process of the redistribution of the magnetisation is due to spin diffusion or due to
inter-chain magnetization transfer through the NOE effect. The latter has been shown
to be of relevance for polymers where a T2-filter selects more mobile side chains [3].
To get a better understanding of the phenomenon, results for mixtures of protonated
chains in a deuterated matrix are also presented.
[1] S.F. Wang, E.D. von Meerwall, S.Q. Wang et al. (2004), Macromolecules 37,
1641.
[2] R. Kimmich, M. Köpf, and P. Callaghan (1991), J. Polym. Sci. B Polym. Phys. 29,
1025.
[3] M. Gaborieau, R. Graf, and H. W. Spiess (2005), Solid State Nucl. Magn. Reson.
28, 160.
Comprehensive 13C Solid State NMR Study of
Electrolyte Decomposition in a Silicon Electrode
Lithium Ion Battery System
A.L. Michan1, M. Leskes2, C.P. Grey3
Alison L. Michan, [email protected]
1-3 Department of Chemistry, University of Cambridge
The solid-electrolyte interphase (SEI) passivating layer that grows on all battery
electrodes during cycling is inherently difficult to study because of its nanoscale
thickness, amorphous composite structure, and air sensitivity, yet its formation and
stability are critical to the long term capacity retention of lithium ion batteries. Here
we employ solid state nuclear magnetic resonance (ssNMR) to gain insight into the
decomposition products in the SEI formed on Si electrodes in a lithium-ion battery
cell, where the uncontrolled growth of the SEI represents a major failure mechanism.
A comprehensive multinuclear ssNMR study and a combination of double resonance
and two-dimensional experimental techniques was performed to probe relative
abundance, structure and spatial proximity of chemical environments in the SEI
formed from a standard battery electrolyte (1M LiPF6 in ethylene carbonate (EC) and
dimethyl carbonate (DMC)). The ssNMR assignments were confirmed by comparison
with the literature and DFT calculations. Using selective 13C labelling, we detect
decomposition products of EC and DMC independently.
DQ NMR study of inhomogeneous microscopiclevel deformation of polymer networks
A. Naumova1, M. Ott2, J. López Valentín3, K. Saalwächter4
Anna Naumova, [email protected]
1, 4 Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg, Halle,
Germany
2 Institut für Physik - Experimentelle Polymerphysik, Martin-Luther-Universität
Halle-Wittenberg
3 Instituto de Ciencia y Tecnología de Polímeros (CSIC), C/Juan de la Cierva, 3,
28006 Madrid, Spain
Residual dipolar interactions measured by NMR methods represent an important
source of information about macromolecular dynamics; in elastomers or gels they
specifically reflect chain-level structural information. The measurement of proton
residual dipolar couplings in an elastomer system is instructive because it reflects the
specific restrictions to molecular motions by cross-linking, topological constraints and
external forces such as mechanical stress [1]. Here, we report double-quantum proton
NMR data of strained samples, which demonstrate that the network chains are not
deformed homogenously but instead have two separated components. One chain
fraction experiences a rather large deformation and has pronounced angular
dependence with respect to the elongation direction. Another fraction is not stretched
significantly and does not show an appreciable angular dependence. This sheds critical
light onto the applicability of theories of network elasticity [1]. In the future we intend
to extend this method to the structure of swollen networks (gels) under stress.
[1] M. Ott, R. Pérez-Aparicio, H. Schneider, P. Sotta, K. Saalwächter,
Macromolecules 2014, 47, 7597–7611.
Water in the Earth's Mantle: 1H-Solid-State NMR
Investigations on Proton Disorder in Ringwoodite
H. Grüninger1, R. Siegel2, T. Boffa-Balleran3, D. Frost4, J. Senker5
Helen Grüninger, [email protected]
1, 2, 5 Inorganic Chemistry III, University of Bayreuth
3, 4 Bavarian Research Institute of Experimental Geochemistry and Geophysics,
University of Bayreuth
The nominally anhydrous silicate minerals present in the earth's mantle, like
ringwoodite (γ-Mg2SiO4), can take up significant amounts of water in the form of
hydroxyl defects.[1,2] The relatively small amounts of defects (max. 3.3 wt% H2O)
have a disproportional high influence on the physical and chemical properties of the
silicates.[1,2] Therefore, a structural elucidation of the defects is essential for a better
understanding of the earth's mantle properties. The discovery of a natural ringwoodite
sample, proving its presence in the mantle, together with its high capacity for water
incorporation, moved ringwoodite in the focus of many researchers.[3,4] With the
combination of high resolution 1H ssNMR (62.5 kHz) and quantum-mechanical
simulations we gained insight in the local structures and disorder of hydrous
ringwoodite. To obtain information about proton connectivities the dipolar
interactions between the protons were reintroduced via symmetry-based pulse
sequences (RNnν-sequences).[5] Multiple proton sites (0-10 ppm) were observed
indicating different water incorporation mechanisms with Mg-OH as well as Si-OH
protons. 2D 1H-1H dipolar correlation spectra and 1D 1H-DQ-buildup curves gave
insight into proton clusters with at least three different 1H-1H distances and thus
different defect sites. Additionally, DFT simulations of multiple defect models suggest
incorporation mechanism with the formation of Si4+- and Mg2+-vacancies as well as
combinations of both. This study reveals a new point of view on the water
incorporation in ringwoodite.
[1] H. Keppler, and J. Smyth, Rev. Mineral. Geochem. (2006), 62, 1.
[2] J. Griffin, and S. Ashbrook, Annu. Rep. NMR Spectrosc. (2013), 79, 241.
[3] D. Pearson, F. Brenker, F. Nestola, J. McNeill, L. Nasdala, M. Hutchinson, S.
Matveev, K. Mather, G. Silversmit, S. Schmitz, B. Vekemans, and L. Vincze , Nature
(2014), 507, 221.
[4] T. Inoue, H. Yurimoto, and Y. Kudoh, Geophys. Res. Lett. (1995), 22, 117.
[5] P. Kristiansen, D. Mitchell, and J. Evans, J. Magn. Reson. (2002), 157, 253.
Probing of Chain Conformations in Conjugated
Polymer Nanoparticles by Electron Spin
Resonance Spectroscopy
C. Hintze1, F. Schütze2, M. Drescher3, S. Mecking4
Christian Hintze, [email protected]
1-4 Department of Chemistry, University of Konstanz, Germany
Conjugated polymer nanoparticles can be obtained either by polymerization in
disperse heterophase systems or by post-polymerization dispersion techniques [1]. The
latter approach has been employed in the form of so-called reprecipitation, in which a
dilute solution of the conjugated polymer in a water-miscible organic solvent is
injected rapidly into an excess of water. The obtained dispersions are colloidally
stable, though the stabilizing mechanism remains unclear [2,3]. Absorbance and
fluorescence spectra of such dispersions suggest that chains have to bend or may even
have kinks, that the particles are very compact, and that there is increased interaction
between segments of the polymer chain [2].
Taken together, understanding chain conformation and crystallinity inside such
nanoparticles is desirable. Here, we make a contribution leading to this goal.
Very small particles are prepared with defined mixtures of monodisperse PEG-OPEs
and monodisperse hydrophobic OPEs. In this case, the particle diameter is smaller
than the chain length and the persistence length [4] of the presumably rigid rod-like
OPEs. This raises the question about the chain conformation inside the nanoparticles.
To elucidate this issue, EPR distance measurements are employed. Doubly endlabeled OPEs are incorporated into the particles. The yielded distance distributions
show that the rigid chains bend in such a defined way as to enable them to fit into the
particle. Furthermore, we present a model for the bending behaviour of the OPEs in
nanoparticles.
[1] J. Pecher, S. Mecking, Chem. Rev. (2010), 110, 6260-6279.
[2] C. Wu, C. Szymanski, J. McNeill, Langmuir (2006), 22, 2956-2960.
[3] J. H. Moon, et al., Angew. Chem. Int. Ed. (2007), 46, 8223-8225.
[4] A. Godt, et al., Angew. Chem. (2006), 118, 7722-7726
NMR evaluation of ionic conductivity for improved
performance of glass-ceramic NASICON
electrolyte membrane
V.A. Vizgalov1, A. Sergeev2, D.M. Itkis3, L.A. Trusov4, M. Motylenko5, E. Brendler6,
A. Vyalikh7
Anastasia Vyalikh, [email protected]
1-3 Department of Materials Science, Moscow State University, Moscow, Russian
Federation
4 Department of Chemistry, Moscow State University, Moscow, Russian Federation
5 Institute of Materials Science, TU Bergakademie Freiberg, Freiberg, Germany
6 Institute of Analytical Chemistry, TU Bergakademie Freiberg
7 Institute of Experimental Physics, TU Bergakademie Freiberg
NASICON-type solid ionic conductors are promising materials for energy storage
devices due to their high ionic conductivity, reasonable chemical and electrochemical
stability. Here we propose a glass-ceramics approach to produce thin gas-tight
electrolyte membranes of a Li1.5Al0.5Ge1.5(PO4)3 composition. Using solid-state NMR
spectroscopy we were able to monitor a transformation from a disordered glass
structure to the glass-ceramics membrane with a random distribution of Al and Ge
octahedra in the NASICON framework. The experimental data are supported by
quantum-chemical calculations of the 31P NMR parameters and intensity estimation
based on a model of random cation distribution.
Adding yttria as a nucleating agent enables to enhance ionic conductivity in glassceramics membrane to 0.5 S cm-1 at room temperature by depressing heterogeneous
crystallization in the glass volume. The NMR data of yttrium-containing glassceramics membranes point out to persistence of the NASICON framework and
formation of a crystalline yttrium phosphate phase. Furthermore, glass crystallization
time has been optimized and analyzed in terms of the structure-property relationship
by a combination of the different experimental techniques. The effect of
crystallization time on ionic conductivity has been found to correlate with the crystal
structure, ionic mobility and morphology determined from 7Li NMR spectroscopy and
relaxometry, neutron diffraction and electron microscopy.
Investigation of Local Structures and Li Ion
Dynamics in Li1.2Al0.6Ti1.4(PO4)3 and
Li1.6Al0.6Ge1.4(PO4)3 by NMR Spectroscopy
S. Indris1, M. Scheuermann2, M. Rhode3, K. Zick4, M. Knapp5, H. Ehrenberg6
Sylvio Indris, [email protected]
1, 2, 5, 6 Insitute of Applied Materials – Energy Storage Systems, Karlsruhe Institute
of Technology, Karlsruhe, Germany
2 Insitute of Applied Materials – Energy Storage Systems, P.O. Box 3640, 76021
Karlsruhe, Germany
3 Insitute of Applied Materials – Applied Materials
4 Bruker Biospin GmbH, Rheinstetten, Germany
We investigated the local structure and the Li ion dynamics in the solid electrolytes
Li1.2Al0.6Ti1.4(PO4)3 and Li1.6Al0.6Ge1.4(PO4)3 by NMR spectroscopy. While 27Al MAS
NMR spectroscopy reveals the presence of almost exclusively octahedral [AlO6]
environments for Li1.2Al0.6Ge1.4(PO4)3, Li1.2Al0.6Ti1.4(PO4)3 exhibits large amounts of
Li located also in tetrahedral [AlO4] environments. 31P MAS NMR measurements
reveal multiple environments with different Al/Ge next nearest neighbor composition
for Li1.2Al0.6Ge1.4(PO4)3. For Li1.2Al0.6Ti1.4(PO4)3, the 31P MAS NMR results indicate
the presence of structural disorder.
These results are confirmed by X-ray diffraction and Rietveld refinements. They show
a well-crystalline phase with Al located exclusively on octahedral sites for
Li1.2Al0.6Ge1.4(PO4)3. For Li1.2Al0.6Ti1.4(PO4)3 a single phase with Al located on
octahedral as well as tetrahedral sites and some indications for disordered components
is revealed.
The dynamics of Li ions have been investigated by temperature-dependent static 7Li
NMR lineshape analysis and 7Li NMR relaxometry. Jump rates of about 7 x 108 s-1
can be estimated for Li1.2Al0.6Ge1.4(PO4)3 at 400 K and the activation barrier for a
single Li ion jump is 0.14 eV. A Li diffusion coefficient of 10-11 m2/s and a Li ion
conductivity of 3.6 mS/cm can be estimated at 400 K. The long-range transport of the
Li ions was investigated by pulsed field gradient (PFG) NMR measurements. These
experiements give slightly lower diffusion coefficients of about 10-12 m2/s for both
samples at 413 K.
Dynamics of Polyacid Chain Segments in
Polyelectrolyte Complexes Studied by Spin-Label
EPR Spectroscopy
U. Lappan1, B. Wiesner2, U. Scheler3
Uwe Lappan, [email protected]
1-3 Leibniz-Institut für Polymerforschung Dresden e. V., Dresden, Germany
The formation of polyelectrolyte complexes (PEC), which are prepared mixing
oppositely charged polyanions and polycations, is controlled by the chemical structure
of the polyions, the concentrations, the mixing ratio, pH, and temperature. Stable
colloidal dispersions of PEC particles are formed when the concentrations are low and
one of the components is taken in excess, resulting in a net charge of the PEC
particles. PEC have a wide range of applications in water treatment and surface
modification.
The weak polyacid poly(ethylene-alt-maleic acid) has been spin-labeled and used to
study the mobility of the polyacid chain segments in complexes formed with the
oppositely charged strong polycation poly(diallyldimethylammonium chloride) in
dependence on mixing ratio [1], pH and temperature [2]. The rotational dynamics of
the nitroxide spin label is characterized by basic and fast cw EPR spectroscopy,
analyzing the line shape.
The study has shown that, if the spin-labeled polyacid is the excess component, the
spectrum of a slow-motion component is superimposed by the spectrum of a fastmotion component. This indicates that the spin labels are located both in the core and
in the shell of the PEC particles. In the opposite case, if the polycation is in excess, the
spectra are dominated by a slow-motion component indicating that nearly all spin
labels are located in the core. The diffusion coefficient characterizing the rotational
motions of the polyacid backbone is significantly smaller at low degree of dissociation
at pH 4 than at high degree of dissociation at pH 7 and pH 10.
[1] U. Lappan, B. Wiesner, U. Scheler, Macromol. Chem. Phys. (2014), 215, 10301035.
[2] U. Lappan, B. Wiesner, U. Scheler, Macromolecules (2015), 48, 3577-3581.
Investigations of polymer dynamics in PEO-silica
nanocomposites
Y. Golitsyn1, G.J. Schneider2, K. Saalwächter3
Yury Golitsyn, [email protected]
1, 3 Institut für Physik – NMR, Martin-Luther-Universität Halle-Wittenberg, Halle
(Saale), Germany
2 Louisiana Center for Neutron Science and Department of Chemistry,
Macromolecular Studies, Louisiana State University, Baton Rouge, LA, USA
Filled elastomers are dispersions of solid particles in polymer networks, and silica
particles are often used as nanofiller materials. Interactions between polymer chains
and nanoparticles can lead to the formation of an adsorbed fraction in the proximity of
the particles' surfaces. This fraction differs from matrix chains by its mobility [1]. In
the current work, time-domain 1H NMR was used for the characterization of such a
composite system based upon poly(ethylene oxide), PEO. Our aim was to clarify the
existence and properties of an immobilized phase in the proximity of the silica
surface, considering opposing statements on its exact nature in the literature [1,2]. For
samples previously studied by neutron scattering [2] it was shown that an immobilized
phase is also present in the case of low molecular weight chains, and that it depends
systematically on the nature of the end groups. On the basis of temperature dependent
measurements it was further proven that the composition and the molecular dynamics
inside the phase differ from that of a fully rigid state. Moisture was further found to
affect the dynamics in the immoblized phase.
[1] S. Y. Kim, H. W. Meyer, K. Saalwächter, C. F. Zukoski. Polymer Dynamics in
PEG-Silica Nanocomposites: Effects of Polymer Molecular Weight, Temperature and
Solvent Dilution. Macromolecules, 2012, 45, 4225.
[2] T. Glomann, G. J. Schneider, J. Allgaier, A. Radulescu, W. Lohstroh, B. Farago,
D. Richter. Microscopic Dynamics of Polyethylene Glycol Chains Interacting with
Silica Nanoparticles. Physical Review Letters, 2013, 110, 178001.
7
Li NMR Study of the Lithium Ion Dynamics in
0.7Li2S + 0.27B2S3 + 0.03B2O3
G. Dost1, M. Haaks2, O. Petrov3, M. Vogel4, S.W. Martin5
Georg Dost, [email protected]
1-4 Institut für Festkörperphysik, Technische Universität Darmstadt
5 Department of Materials Science and Engineering, Iowa State University of Science
and Technology
During the last decades lithium ion batteries have been extensively studied due to the
higher energy density in comparison to the common nickel based batteries. As fluid
electrolytes pose different hazards, solid state electrolytes like glass are of interest. For
such an application the lithium ion dynamics in this unordered material play an
important role.
The dynamic is described by the activation energy for the movement of a lithium ion.
NMR spectroscopy offers several methods to obtain this parameter e.g. relaxometry
and spin alignment experiments [1].
Here we report on our 7Li NMR study of 0.7Li2S + 0.27B2S3 + 0.03B2O3 glass. The
first component is used as lithium-sulfur batteries show great potential [2]. The other
components are glass formers possibly showing the mixed glass former effect [3].
The measurements were performed with a pulse NMR spectrometer at 76 MHz in a
temperature range of 142 to 300 K.
The temperature dependence of the lithium spin-lattice relaxation times T1 yields the
activation energy of the ion dynamics.
The correlation function depicts how fast the ions change their current position and is
characterized by the correlation time τ.
Using Kohlrausch Williams Watts functions and the Bloemberg Purcell Pound model
the activation energy was obtained for both experiments.
[1] R. Böhmer, K. R. Jeffrey, M. Vogel. Prog. in NMR Spec. (2007), 50, 87-174
[2] M. Tatsumisago, H. Yamashita, A. Hayashi, H. Morimoto, T. Minami. J. NonCryst. Solids (2000), 274, 30–38
[3] Y. Kim, J. Saienga, and S. W. Martin. J. Phys. Chem. B (2006), 110, 1631816325
Correlation between structure and alkali corrosion
behaviour of potassium alumosilicates as seen by
27
Al and 29Si Solid State NMR and chemometric
methods
A. König1, N. Brachhold2, M. Schmidt3, E. Brendler4, C.G. Aneziris5, M. Otto6
Erica Brendler, [email protected]
1, 3, 4, 6 Institute of Analytical Chemistry, TU Bergakademie Freiberg
2, 5 Institute of Ceramic, Glass and Construction Materials, TU Bergakademie
Freiberg
Alumosilicates have many applications, an important one being specialized furnace
linings in high temperature processes. There, a problem is the alkali load originating
from raw materials and fuels, which initiates alkali corrosion. Especially secondary
fuels introduce a higher alkali load compared to fossil fuels thereby increasing
corrosion problems [1]. For the efficient development of alkali resistant lining
materials [2] understanding the determining structural features for alkali stability is
essential.
Selected samples within the system K2O:Al2O3:SiO2 were tested regarding their alkali
stability. The samples were characterised before and after alkali corrosion treatment
by XRD, 27Al MAS, 27Al MQMAS, and 29Si MAS NMR. The aim of the structural
investigation was to establish a correlation between structural features and corrosion
stability. The direct evaluation of the spectroscopic results indicated that not a certain
component could be correlated to the stability. In a next step chemometric methods
were implemented to analyse the structure-property relation. Among several methods,
the partial least squares regression (PLS) using the 29Si MAS NMR spectra eventually
allowed for the discrimination of the samples regarding their stability. The starting
samples can be separated by two PLS components, samples after the corrosion test by
only the first PLS component. Evaluation of the PLS coefficients shows that the
spectral region -85 to -95 ppm, representing orthorhombic KAlSiO4 and kaliophilite,
has the largest influence on the stability prediction.
[1] C.G. Aneziris, U. Fischer, E. Schlegel, Keram. Z. (2008), 60, 347-351.
[2] N. Brachhold, C. G. Aneziris, Int. J. Appl. Ceram. Technol. (2013), 10 (4), 707-15.
Electrical Functional Materials investigated by
means of Solid State-NMR
P.B. Groszewicz1, H. Breitzke2, W. Jo3, M. Gröting4, R. Dittmer5, E. Sapper6,
K. Albe7, J. Rödel8, G. Buntkowsky9
Pedro Braga Groszewicz, [email protected]
1, 2, 9 Institute of Physical Chemistry, Technische Universität Darmstadt, Darmstadt,
Germany
3 School of Materials Science and Engineering, Ulsan National Institute of Science
and Technology, Ulsan, Republic of Korea
4-8 Institute of Materials Science, Technische Universität Darmstadt, Darmstadt,
Germany
23
Na ssNMR is employed to investigate lead-free piezoelectric ceramics of
composition (100-x)(Bi1/2Na1/2)TiO3 – (x)BaTiO3, with 0≤x≤15. It can be shown that
these materials are disordered at the atomic scale. The degree of local disorder and the
individual contribution of the chemical shift and quadrupole interactions are
characterized by 3QMAS experiments as a function of barium content.
The chemical shift is identified as a fingerprint of the average rhombohedral or
tetragonal symmetries exhibited by this material. Nevertheless, locally, a distribution
of chemical shift is found; its width peaks for compositions with the highest
piezoelectric coefficient. These results indicate that a wider variety of local
symmetries might be related to enhanced electric properties.
A distribution of electric field gradients is also observed, which correlates to the
material’s spontaneous electric state (ferroelectric of relaxor) as a function of barium.
DFT calculations demonstrate this NMR parameter is connected to tilting of TiO6
octahedra in the perovskite structure. Hence, suggesting that the atypical relaxor-toferroelectric crossover, induced by barium doping in this system, is heavily influenced
by disorder in the octahedra tilt system.
At last, by comparing the quadrupole perturbed 23Na NMR lines of samples before
and after electric poling, we reveal the coexistence of cubic and polar phases for
relaxor compositions. This result supports a model of polar nanoregions (PNRs)
embedded in a cubic non-polar matrix for the ground state of these lead-free relaxors.
[1] P. B. Groszewicz, H. Breitzke, R. Dittmer, E. Sapper, W. Jo, G. Buntkowsky, and
J. Rödel, PHYSICAL REVIEW B 90 220104(R) (2014)
An advanced structure study of cellulose hybrid
materials by solid-state dynamic nuclear
polarization (DNP) NMR
L. Zhao1, W. Li2, A. Plog3, G. Buntkowsky4, T. Gutmann5, K. Zhang6
Li Zhao, [email protected]
1, 4, 5 Eduard-Zintl-Institute for Inorganic Chemistry and Physical Chemistry,
Technische Universität Darmstadt, Darmstadt, Germany
2, 3 Center of Smart Interfaces, Technische Universität Darmstadt
6 Wood Biology and Wood Products, Burckhardt Institute, University of Göttingen
Crystalline nano cellulose in the form of cellulose nanocrystals (CNC) has attracted
increasing interest in the last few years. [1] CNC hybrid materials have been applied
in vast fields, e.g stimuli-responsive films. The structure determination of functional
groups on CNC surfaces however constitutes a significant challenge, partially due to
their low amounts.
Solution NMR techniques were generally used to study rhodamine derivatives and
their behavior under the influence of external stimuli. However, solution NMR shows
limitations for hybrid materials, which cannot be dissolved by common solvents.
Solid-state NMR spectroscopy coupled with dynamic nuclear polarization (DNP)
allows the measurement of 13C, 15N and 17O NMR spectra in natural abundance [2-3]
Thus, it might be also a powerful tool for the determination of structural changes
during the switching process.
In this study [4], rhodamine spiroamide groups are immobilized onto the surface of
CNC leading to a hybrid compound being responsive to pH-value, heating and UV
light. After the treatment with external stimuli, the fluorescent and correlated optical
color change is induced, which refers to a ring opening and closing process.
Furthermore, it is firstly shown that a temporary bond through an electrostatic
interaction could be formed within the confined environment on the CNC surface
during the heating treatment, while the carboxyl groups on CNC surface plays a
pivotal role in stabilizing the open status of rhodamine spiroamide groups.
[1] D. Klemm, et al., Angew. Chem. (2013), 50, 5438-5466.
[2] T. Gutmann, et al., Chem. (2015), 21, 3798-3805.
[3] T. Wang, et al., Proc. Natl. Acad. Sci. (2013), 110, 16444-16449.
[4] L. Zhao, et al., Phys. Chem. Chem. Phys. (2014), 16, 26322-329.
Applications of Solid State Dynamic Nuclear
Polarization NMR on Heterogeneous Catalysts
A.S. Thankamony1, O. Lafon2, D. Carnevale3, V. Polshettiwar4, T. Gutmann5, G.
Buntkowsky6
Aany Sofia Lilly Thankamony, [email protected]
1, 5, 6 Institute of Physical Chemistry, Technische Universität Darmstadt, Germany
2 Univ. Lille Nord de France, CNRS UMR 8181, UCCS, Villeneuve d’Ascq, France
3 ISIC, EPFL, Batochime, Lausanne, Switzerland
4 NanoCat, TIFR, Mumbai, India
Modern heterogeneous catalysts are employed in large-scale quantities in industrial
chemical processes. They often exhibit complex hierarchical structures on nano- and
meso-scopic length scales. Their energy efficiency and environmental compatibility
are a consequence of their composition and processes on their surfaces. Until now
material scientists rely on a purely explorative approach for optimizing these
properties. A tailored design will be possible based only on a detailed knowledge
about the atomistic processes and dominating interactions on their surfaces. Dynamic
Polarization (DNP)-enhanced solid-state NMR spectroscopy poses a unique way to
address such questions [1]. DNP-enhanced solid-state NMR probes molecular level
information at these surfaces with unprecedented sensitivity. Here the application of
solid-state DNP-NMR on Mo/V/W mixed oxide heterogeneous catalysts is
demonstrated which are important stable technical catalysts used for the partial
oxidation of acrolein to acrylic acid [2]. 51V NMR is used to obtain information on the
environment of different vanadium species which are influenced by molybdenum and
tungsten moieties. In a further example DNP is applied for the catalytic activity
studies of solid-base catalysts, fibrous nanosilica (KCC-1) oxynitrides [3]. As the
nitrogen content of these catalysts increases, their catalytic activity decreases. This
counterintuitive observation is explained by using DNP enhanced 15N-solid-state
NMR.
[1] T. Maly, et al., J. Chem. Phy. 128, (2008), 052211
[2] P. Kampe, et al., Phys. Chem. Chem. Phys, (2007), 9, 3577–3589
[3] A. S. Thankamony, et al., Angew. Chem. Int. Ed. 53 (2014), 2190-2193
Hydrogen/Deuterium Exchange and Ammonia Adsorption
on Ligand Stabilized Metal Nanoparticles Investigated by
Gas Phase and Solid State NMR
N. Rothermel1, T. Gutmann2, K. Philippot3, B. Chaudret4, G. Buntkowsky5
Niels Rothermel, [email protected]
1, 2, 5 Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische
3 Laboratoire de Chimie de Coordination du CNRS, Toulouse
4 LABORATOIRE DE PHYSIQUE ET CHIMIE DE NANO-OBJETS, Institut National
des Sciences Appliquées, Toulouse
The reactivity of hydrides on the surface of ligand stabilized metal nanoparticles
(MNPs) is investigated by an isotope exchange with deuterium employing
acombination of 1H gas phase- and 2H low temperature solid state NMR. This study
aims to gain a better understanding of H/D exchange reactions catalyzed by MNPs,
which are for example employed in the selective deuteration of bioactive aza
compounds [1]. The systems under investigation are mono- and bimetallic particles of
ruthenium, platinum and Ru/Pt respectively. For the stabilization of the nanoparticles,
1,4-bis(diphenylphosphino)butane (dppb) is employed in the context of the
organometallic synthesis of the particle systems [2–4]. Time dependent 1H gas phase
NMR measurements during the isotope exchange are used to compare the exchange
kinetics of the systems under investigation. Low temperature 2H solid state NMR is
utilized to distinguish between different binding sites of hydrogen on the surface of
the MNPs [5,6], thus being a tool of great value for the characterization of such
complex nanoparticle systems. The MNP’s are further investigated with respect to
their H/D exchange activity in the deuteration of alkanes.
In a second study adsorbed ammonia on the surface of Ru/dppb is investigated by
solid state NMR. This investigation will help to understand the behavior of NH3 on
the MNP surface and is a starting point for the development of catalytical reactions
involving NH3 such as the Haber-Bosch process or the synthesis of organic molecules
such as urea.
[1] G. Pieters, et al., Angew. Chem. Int. Ed. Engl. (2014), 53, 230.
[2] F. Novio, K. Philippot, B. Chaudret, Catal. Letters (2010), 140, 1.
[3] P. Lara, T. Ayvalı et al., Dalton Trans. (2013), 42, 372.
[4] S. Kinayyigit, P. Lara et al., Nanoscale (2014), 6, 539.
[5] T. Gutmann, I. Del Rosal et al., Chemphyschem (2013), 14, 3026.
[6] T. Gutmann, et al., Solid State Nucl. Magn. Reson. (2013), 55-56, 1.
Solid State NMR as a Powerful Tool for
Characterization and Understanding of
Immobilized Dirhodium (II) Catalysts
J. Liu1, T. Gutmann2, Y. Xu3, K. Zhang4, P.B. Groszewicz5, L. Zhao6, A.S.
Thankamony7, N. Rothermel8, H. Breitzke9, G. Buntkowsky10
Jiquan Liu, [email protected]
1-3, 5-10 Eduard-Zintl-Institute for Inorganic Chemistry and Physical Chemistry ,
Technische Universität Darmstadt, Germany
4 Wood Technology and Wood Chemistry, University of Göttingen, Germany
In this work, homogeneous Rh2 (OOCCH3)4 and Rh2 (OOCCF3)4 catalysts are
anchored on the surface of carboxyl-amine bi-functional SBA-15 and cellulose
nanocrystals (CNC).[1,2] Solid state NMR is employed to study their structures and
binding sites.
For bi-functional SBA-15, in principle the Rh2 (OOCCH3)4 can be anchored by amine
and/or carboxyl groups via axial coordination and ligand substitution.[1] 13C CP MAS
DNP NMR confirms carboxyl binding sites by ca. 10 ppm low-field shift of carbonyl
group after immobilization of dirhodium unit. 15N CP MAS DNP NMR highlights that
in addition the amine groups coordinate the dirhodium unit at axial position by a novel
signal at -402.7 ppm, while the amine group located around -349.0 ppm. These results
are corroborated by quantum chemical calculations as well as liquid state NMR using
15
N HMBC. Both experiments indicate that the dirhodium unit is bound via an amine
and/or carboxyl group in the pores of SBA-15.
For CNC immobilized dirhodium catalyst, the Rh2 (OOCCF3)4 is anchored on the
CNC surface via carboxyl groups by ligand exchange, which is confirmed by a 15
ppm low-field shift of the carbonyl group in the 13C CP MAS NMR, while the
carboxylate group on CNC (salt form) is visible at 173 ppm. [2] By combination of
the thermogravimetric analysis and quantitative 19F MAS NMR analysis, it is
demonstrated that two CF3COO- groups are averagely replaced during the ligand
exchange process.
[1] T. Gutmann, J. Liu, N. Rothermel, Y. Xu, E. Jaumann, H. Breitzke, S. Sigurdson,
G. Buntkowsky, Chem. Eur. J., (2015),21, 3798-3805
[2] J. Liu, A. Plog, P. Groszewicz, L. Zhao, Y. Xu, H. Breitzke, A.Stark, R.
Hoffmann, T. Gutmann, K. Zhang, G. Buntkowsky, Chem. Eur. J., (Accepted)
Time-Resolved EPR and Theoretical
Investigations of Excited Triplet States of
Thiophene-Decorated Phenazines
H. Matsuoka1, L. Röck2, M. Retegan3, F. Neese4, C. Bannwarth5, S. Grimme6, S.
Höger7, O. Schiemann8
Hideto Matsuoka, [email protected]
1, 8 Institute for Physical and Theoretical Chemistry, University of Bonn
2, 7 Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn
3, 4 Max Planck Institute for Chemical Energy Conversion
5, 6 Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical
Chemistry, University of Bonn
Organic light-emitting diodes (OLEDs) have attracted significant attention for the
application in next generation display technologies. In OLEDs using fluorescent
emitters, internal quantum efficiency is limited to about 25%. Introduction of
phosphorescent emitters allows to take advantage of spin statistics and to raise this
limit. Recently, triplet harvesting without heavy atoms has also been explored.
Thiophene-decorated phenazines are an example for this. They showed both
fluorescence and phosphorescence even at room temperature [1].
We have performed time-resolved EPR and theoretical studies on the excited triplet
state of a series of such phenazines. It was demonstrated that the electronic
structures/energy levels of the excited states are affected by the orientation of the
thiophene rings as well as the number of thiophene rings. The electronic
structures/energy levels tuned by molecular design resulted in a perturbation of the
luminescent properties. For example, some thiophene-decorated phenazines exhibited
both fluorescence and phosphorescence, whereas the others didn’t show any
phosphorescence. Time-resolved EPR is a powerful tool to investigate experimentally
non-phosphorescent triplet states as well as phosphorescent ones. The EPR derived
lifetimes, zero-field splitting parameters, and theoretical spin density distributions of
the excited triplet states depend on the ring orientation and/or the number of thiophene
rings. A symmetry consideration indicated that the optical properties can be
influenced by the orientation.
[1] D. Chaudhuri, E. Sigmund, A. Meyer, L. Röck, P. Klemm, S. Lautenschlager, A.
Schmid, S. R. Yost, T. Van Voorhis, S. Bange, S. Höger, and J. M. Lupton, Angew.
Chem., 2013, 125, 1-5.
Triplet Exciton Formation in High-Efficiency
Donor-Acceptor Photovoltaic Blends
S. Väth1, K. Tvingstedt2, A. Baumann3, A. Sperlich4, V. Dyakonov5, J. Love6, T.-Q.
Nguyen7
Stefan Väth, [email protected]
1, 2, 4 Experimental Physics VI, Julius Maximilian University of Würzburg,
Würzburg, Germany
3 ZAE Bayern, Würzburg, Germany
5 Experimental Physics VI, Julius Maximilian University of Würzburg / ZAE Bayern,
Würzburg, Germany
6, 7 University of California at Santa Barbara, Santa Barbara, CA 93106, USA
In donor-acceptor based bulk-heterojunction solar cells, the splitting of singlet
excitons at the donor and acceptor interface is of crucial importance for charge
generation. The reversed process, in which two initially free charge carriers meet at
the interface to form an exciton with singlet or triplet multiplicity is rather beneficial
for light emission in OLEDs but considered as one of the loss factors in OPV [1].
In our experiments, the occurrence of triplet excitons and CT states was probed by
using spin sensitive detection of the photo- and electroluminescence. A substantial
generation of molecular triplet excitons was found in high efficiency donor-acceptor
OPV systems based on the low bandgap copolymer PTB7 and in the soluble small
molecule p-DTS(FBTTh2)2 [2], both blended with PC70BM as acceptor. We ascribe
these findings to an electron back transfer from the CT state to the triplet state on the
donor material.
In summary, the fundamental understanding of the transformation processes involving
the CT states, triplet excitons, as well as free electrons and holes and their dependence
on nanoscale morphology and energetics of blends is essential for the optimization of
OPV devices.
[1] M. Liedtke, A. Sperlich, H. Kraus, A. Baumann, C. Deibel, M. J. M. Wirix, J.
Loos, C. M. Cardona, and V. Dyakonov, J. Am. Chem. Soc. (2011), 133, 9088–9094.
[2] T. S. van der Poll, J. A. Love, T.-Q. Nguyen, and G. C. Bazan, Advanced
Materials (2012), 24, 3646.
High temperature in-situ and ex-situ high
temperature SSNMR studies of Sodium Aluminum
Metaphosphate Glasses
S. Venkatachalam1, L. van Wüllen2
Sabarinathan Venkatachalam, [email protected]
1, 2 Lehrstuhl für Chemische Physik und Materialwissenschaften, Institut für Physik,
Universität Augsburg
Sodium Aluminum Metaphosphate (NAP) glasses with high molar concentrations of
Al were prepared via melt-quench technique; reported to be inaccessible. High
resolution solid state 31P, 27Al, and 23Na MAS nuclear magnetic resonance
spectroscopy were used to study the structural characterization of amorphous solids.
Besides quadrupolar and spin-1/2 nuclei were performed to determine the connectivity
and spatial interaction statistics. These include rotational echo double resonance
(REDOR) and rotational adiabatic passage double resonance (REPDOR) experiments,
HETCOR and Multiple quantum MAS. The result of these experiments explains the
structural changes below and above the glass transition temperature, Tg and near the
crystallization temperature Tc.
Structure, phase separation and Li dynamics in
solid electrolyte Li1+xAlxGe2-x(PO4)3, studied by
solid state NMR
Z. Liu1, S. Venkatachalam2, H. Kirchhain3, L. van Wüllen4
Zhongqing Liu, [email protected]
1-4 CPM, Institute of Physics, University of Augsburg
In our study, various fast lithium ion conductors of Li1+xAlxGe2-xP3O12 (LAGP, 0 - x 1.0) have been synthesized following a melt-quenching or sol-gel process with
subsequent annealing (650°C-1050°C). Their components, structures and dynamics
were investigated by means of X-ray diffraction and solid state nuclear magnetic
resonance (solid state NMR). From the XRD patterns, all the main diffraction peaks
can be assigned to the LAGP phase with a NASICON-type structure [1]. According to
the static 7Li-NMR spectra, all samples show good Li ion motilities (FWHM approx.
600-1000 Hz). Employing heteronuclear dipolar NMR techniques, i.e. 27Al{31P}REDOR NMR and 31P{27Al}-REAPDOR NMR, it allows us to clearly assign the
different 31P-MAS-NMR signals to P(OAl)n(OGe)4-n species with 0 - n - 3. The
tetrahedrally coordinated Al is shown to be incorporated in an extra AlPO4 phase, thus
not participating in the NASICON structure. [2,3] Among our studies, apart from
crystalline impurity phases such as AlPO4, Li4P2O7 and GeO2 [4], an additional phase
Li9Al3(P2O7)3(PO4)2 is observed in Al-rich samples (x - 0.7), giving rise to a
compositional limit of Al content as x-0.6. In addition, the LAGP phase
transformation from glass to crystal was independently checked by situ-NMR
experiments.
[1] J.B. Goodenough, H.Y.-P. Hong, J.A. Kafalas, Mater. Res. Bull. 11 (1976) 203.
[2] C. Schröder, J.Ren, A. C. M. Rodrigues, H. Eckert, J. Phys. Chem. C. 118 (2014)
94
[3] Z. Liu, S. Venkatachalam, L. van Wüllen Solid State Ionics 276 (2015) 47.
[4] M. Cretin and P. Fabry, J. Eur. Ceram. Soc. 19 (1999) 2931.
NMR Investigation of Carbon Fibers and their
effect to polymerization of epoxy resin
A. Nizamutdinova1, S. Venkatachalam2, L. van Wüllen3
Alina Nizamutdinova, [email protected]
1-3 Lehrstuhl für Chemische Physik und Materialwissenschaften, Institut für Physik,
Universität Augsburg, Germany
High-strength carbon fibers having different surface treatment (oxidized, stabilized
and untreated) were studied with high resolution MAS nuclear magnetic resonance
spectroscopy. This included CP-MAS and spin echo MAS. The effect of different
carbon fibers and to the polymerization process of epoxy resin was investigated by
means of CP-MAS NMR experiments
Effects of Confinement on the Dynamics of
Aqueous Mixtures
M. Sattig1, M. Reuhl2, M. Vogel3
Matthias Sattig, [email protected]
1-3 Institut für Festkörperphysik, Technische Universität Darmstadt, Germany
The dynamical behavior of aqueous mixtures in bulk and in confinement is a topic of
great interest. For example, a water concentration dependend behavior of the glass
transition temperature was found in PG-water and in PGME-water mixtures, which is
very different for the two cases [1]. This was attributed to different possibilities of
both molecules to form H-bonds in the bulk and different mechanisms of H-bonding
in the presence of additional water. The forming of H-bonds can be disturbed by
introducing a geometrical confinement, whose surface interacts with the guest
molecules and spatially restricts the bond network.
Here, we present rotational correlation times τ of both above mentioned mixtures in
bulk and in confinement at several water concentrations, obtained from DeuteronNMR on a time scale from ns up to s. Mesoporous silica MCM-41 was employed as
confinement. In the high temperature regime spin-lattice-relaxation experiments show
similar results for both mixtures in bulk and in confinement. At lower temperatures
they hint at the occurrence of a phase separation, assisting the interpretation from
Elamin et al. [1]. They propose the idea of water clustering at the surface. The present
results are compared with results from dielectric spectroscopy [1] of the mixtures in
bulk and confinement. Similarities with water confined in MCM-41 are discussed,
where the observable relaxation at low temperatures was attributed to surface layer of
water [2,3]. In addition a comparison to water on protein surfaces [4] is drawn.
[1] K. Elamin, PhD Thesis (2015), Chalmers University, Gothenburg
[2] M. Sattig, M.Vogel, J. Phys. Chem. Lett., 2014, 5, 174–178
[3] M. Sattig et al., Phys. Chem. Chem. Phys., 2014, 16, 19229-19240
[4] Lusceac et al., BBA, 2010
7
Li NMR studies of lithium ion dynamics in
ceramics
M. Haaks1, S.W. Martin2, M. Vogel3
Michael Haaks, [email protected]
1, 3 Condensed Matter Physics, Technische Universität Darmstadt, Germany
2 Material Sciences and Engineering, Iowa State University of Science & Technology,
Ames, IA, USA
Rising energy demand makes it important to improve the performance of lithium ion
batteries. For this purpose it is important to understand the dynamics of lithium ions,
in particular, in heterogeneous materials, which are used in modern strategies for
material optimization. Combining spin-lattice relaxation, solid-echo, and stimulatedecho experiments, 7Li NMR allows us to expand the accessible time scale of ion
dynamics to about 10 orders of magnitude. We exploit this potential to study ion
dynamics in mixed network former glasses and in complex ceramics. Investigations of
the mixed network former glass 0.5Li2S-0.5(xGeS2-(1-x)GeO2) reveal the importance
of a broad distribution of correlation times and, consequently, activation energies of
the lithium ionic jump motion [1]. Studies of 0.7Li2S-0.3P2S5 show that not only the
electric conductivity, but also the ionic jump rates are enhanced by ceramization.
[1] J. Gabriel, O.V. Petrov, Y. Kim, S.W. Martin, and M. Vogel, Solid State Nucl.
Magn. Reson. (2015), Article in Press
2
H NMR on fluids in soft confinement
M. Lannert
Michael Lannert, [email protected]
AG Vogel, Institut für Festkörperphysik, TU Darmstadt
2
H NMR allows us to access correlation times of molecular rotational dynamics,
ranging from 10e-12 to 10e-1 s, by using longitudinal relaxation, solid echo, and
stimulated echo sequences. Findings for confined glycerol, which is subjected to
spherical soft confinement (using AOT/toluene micro-emulsions) and cylindrical hard
confinement (using microporous silica, namely MCM-41) are compared, and a shift in
correlation times to shorter times is observed for the hard confinement, but not for the
soft confinement. Various diameters (2 nm to 9 nm) were used in order to gain a
comprehensive understanding of the finite size effect. Investigation of the dynamics of
the glycerol in the supercooled regime proved to be a challenging enterprise in soft
confinement, because of the onset of rotational diffusion of the whole microemulsion
droplet, which exceeds the contribution of molecular rotational dynamics.
Therefore droplet size-dependence and viscosity-dependence of the dynamics where
investigated additionally, in order to evaluate the impact of these results.
Diffusive Diffraction of Cylinders in the 100 nm
Range
S. Reutter1, F. Fujara2, C. Trautmann3
Stefan Reutter, [email protected]
1, 2 Institut für Festkörperphysik, Technische Universität Darmstadt, Darmstadt,
Germany
3 GSI Helmholtzgesellschaft für Schwerionenforschung, Darmstadt, Materials
Sciences
Diffusive Diffraction [1,2] is a field gradient imaging experiment which is sensitive to
the translational motion of spins within an ensemble over a certain mixing time rather
than their position distribution at a fixed time. Therefore, it is an excellent tool to
measure the form factor of a sample containing a large number of sub-samples with a
similar size and shape, such as a matrix of cylindrical channels through a membrane.
A description of the technique will be presented, as well as data from several such
matrices with cylindrical pores of different radii (in the few 100 nm range) measured
in a static field gradient spectrometer, and a comparison of the data to theoretical
calculations [3] in order to estimate their respective pore radii.
[1] P. T. Callaghan, D. MacGowan, K. J. Packer, and F. O. Zelaya. High-resolution qspace imaging ... J. Mag. Res. (1969), 90(1):177-182, 1990. doi: 10.1016/00222364(90)90376-K.
[2] P. T. Callaghan. Pulsed-Gradient Spin-Echo NMR ... J. Mag. Res. A, 113(1):5359,1995. doi: 10.1006/jmra.1995.1055.
[3] Spin Echo Analysis of Restricted Diffusion ... J. Mag. Res., 137(2):358-372, 1999.
doi: 10.1006/jmre.1998.1679.
212 Materials in Solution / Polymers / Catalysis
Correlating Crystallization Kinetics and
Rheological Properties of Polyethylene Using a
New Low-Field Rheo-NMR Combination
M.B. Özen1, V. Räntzsch2, K.-F. Ratzsch3, M. Wilhelm4
Mürüvvet Begüm Özen, [email protected]
1-4 Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe
Institute of Technology (KIT), Karlsruhe, Germany
Polyethylene (PE) along with its copolymers constitutes around 30% of the worldwide
plastics production and it is used in a wide variety of consumer products. During
thermoplastic processing, orientation of polyethylene chains due to flow under
supercooling causes shear-induced crystallization and affects the final crystallinity of
the product, with a strong impact on the mechanical properties of the product. From
the point of view of polymer processing, parameters such as molecular weight and
distribution, branching properties and processing conditions such as the deformation
strain, deformation rate and temperature (including the cooling rate) play crucial roles
in the sensitivity of the polymer crystallization to deformation. Low-field (time
domain) NMR is a useful tool to quantitatively investigate and monitor the molecular
dynamics in the phases of a crystallizing polymer [1]. Shear induced crystallization
experiments can be run in a laboratory rheometer [2], making it at promising idea to
integrate the NMR measurement into it.
Our home-built unique low-field Rheo-NMR setup as a combination of a permanent
magnet with 0.7 T (30 MHz proton resonance) in a commercial rheometer is a
technique to investigate shear induced crystallization of polyolefins. This unique
combination can measure a full rheological shear characterization (G’, G’’, LAOS,
I3/1, FT-Rheology [3]) and the development of crystallinity at once [4]. The aim of this
work is to investigate for the first time the crystallization kinetics of PE via this new
combined Rheo-NMR method.
[1] A. Maus, C. Hertlein, and K. Saalwächter, Macromol. Chem. Phys. (2006), 207,
1150-1158.
[2] T. Dötsch, M. Pollard, and M. Wilhelm, J. Phys.: Condens. Matter (2003), 15,
923-931.
[3] K. Hyun, C. O. Klein, M. Wilhelm, K. S. Cho, J.G. Nam, K. H. Ahn, J. S. Lee, R.
H. Ewoldt, and G. H. McKinley, Prog. Polym. Sci. (2011), 36, 1697.
[4] V. Räntzsch, M. Wilhelm, and G. Guthausen, Magn. Reson. Chem. (2015), DOI
10.1002/mrc.4219.
Crystallization of Polypropylene Materials Studied
by Low-Field RheoNMR
V. Räntzsch1, M.B. Özen2, K.-F. Ratzsch3, J.K. Palacios4, A.J. Müller5,
G. Guthausen6, M. Wilhelm7
Volker Räntzsch, [email protected]
1, 2, 6, 7 Karlsruhe Institute of Technology, Karlsruhe, Germany
3 Karlsruhe Institute of Technology, Karlsruhe / University of Freiburg, Freiburg,
Germany
4 University of the Basque Country, Donostia-San Sebastián, Spain
5 University of the Basque Country, Donostia-San Sebastián / IKERBASQUE,
Basque Foundation for Science, Bilbao, Spain
Materials based on polymers and additives such as reinforcing fillers, pigments or
anti-static agents are ubiquitous in today’s material science due to their mechanical,
optical and electrical properties. A thorough understanding of the influence of additive
type, shape and content on the molecular dynamics of polymer chains with
implication on processes such as polymer crystallization is necessary for the
determination of structure-property relationships and the development of theories for
the prediction of material properties. In order to clarify these relations, model systems
based on isotactic polypropylene and nanosilica were prepared and characterized
using a new low-field RheoNMR technique [1-3] which relies on the implementation
of a portable low-field 30 MHz TD-NMR unit in a commercial rheometer. By
studying the isothermal crystallization simultaneously with TD-NMR and rheometry,
a correlation of microscopic molecular dynamics and the macroscopic mechanical
response during polymer crystallization was achieved. The systematic investigation of
different filler contents and a comparison with other methods such as benchtop lowfield NMR and differential scanning calorimetry (DSC) [4] led to new insights in the
role of fillers during the crystallization of polymers.
[1] S. Kahle, W. Nussbaum, M. Hehn, H. P. Raich, M. Wilhelm, and P. Blümler,
Kaut. Gummi Kunstst. (2008), 61, 92–94.
[2] V. Räntzsch, K.-F. Ratzsch, G. Guthausen, S. Schlabach, and M. Wilhelm, Soft
Mater. (2014), 12, S4–S13.
[3] V. Räntzsch, M. Wilhelm, and G. Guthausen, Magn. Reson. Chem. (2015), in
print. doi:10.1002/mrc.4219
[4] A. T. Lorenzo, M. L. Arnal, J. Albuerne, and A. J. Müller, Polymer Test. (2007),
26, 222–231.
Red Phosphorus in Ionic Liquids - Reaction
monitoring by NMR spectroscopy
S. Paasch1, M. Groh2, A. Weiz3, M. Ruck4, E. Brunner5
Silvia Paasch, [email protected]
1, 5 Bioanalytische Chemie, Fachrichtung Chemie und Lebensmittelchemie, TU
Dresden
2-4 Anorganische Chemie 2, Fachrichtung Chemie und Lebensmittelchemie, TU
Dresden
Reactions in ionic liquids enable the synthesis of various inorganic materials under
mild conditions. This result in an enormous reduction of energy usage and technical
efforts compared to the commonly applied high-temperature processes. Moreover,
completely new compounds with potentially outstanding and useful chemical and
physical properties can be discovered. [1]
As example, we selected the reaction of red phosphorus with iodine in the Lewis acid
[BMIm]Cl•2AlCl3 as ionic liquid. For the understanding of this reaction process 31P
HR NMR spectroscopy assisted by solid-state NMR was used as the method of choice
for continuous reaction monitoring. Varying temperature and ratios of starting
materials, the reaction process and products were investigated. The formation of P2I4
was expected [1], but the reaction intermediates had to be identified based on NMR
spectroscopy. Depending on the ratio of red phosphorus and iodine in the starting
solution, P2I4, PI3 and P2I5+ appear as main final products at different concentrations.
Furthermore, nanoscale red phosphorus particles could be discovered in reaction
solution as well as by dissociation of P2I4 in the ionic liquid. [2]
[1] M. F. Groh, U. Müller, E. Ahmed, A. Rothenberger, M. Ruck: “Substitution of
Conventional High–Temperature Syntheses of Inorganic Compounds by Near–Room–
Temperature Syntheses in Ionic Liquids” Z. Naturforsch. (2013) 68b, 1108
[2] M. F. Groh, S. Paasch, A. Weiz, E. Brunner, M. Ruck: “Unexpected Reactivity of
Red Phosphorus in Ionic Liquids” Eur. J. Inorg. Chem. (2015) DOI:
10.1002/ejic.201500502
Spin relaxation study of 7Li dynamics in polymer
gel electrolytes
M. Brinkkötter1, M. Gouverneur2, F. Vaca Chávez3, P. Sebastião4, M. Schönhoff5
Monika Schönhoff, [email protected]
1, 2, 5 Institute of Physical Chemistry, University of Muenster, Münster, Germany
3, 4 Departamento de Fisica, Instituto Superior Technico, Universidade de Lisboa,
Portugal
Ternary polymer gel electrolytes consisting of an ionic liquid, a polymer and a lithium
salt are promising materials for a compromise between sufficient conductivity and
mechanical stability in lithium ion conducting battery electrolytes. In particular,
poly(ionic liquids) such as for example poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl) imide (PDADMATFSI) were recently introduced as the polymeric
component [1-4].
Here, we compare two ternary polymer electrolyte systems, containing either
PDADMATFSI or polyethylene oxide (PEO), which are based on the ionic liquid 1butyl-1-methylpyrrolidinium bis(trifluoromethyl-sulfonyl)imide (P14TFSI) and
LiTFSI. We study the influence of the polymers on the local lithium ion dynamics at a
constant lithium ion concentration using R1 relaxation rates determined at different
frequencies and temperatures. We conclude that the local lithium mobility and the
local lithium environment is influenced by the type of polymer and by the polymer
concentration. It is possible to describe the data by a motional model of the Li
dynamics: We fit the lithium data assuming the Cole-Davidson model with Arrhenius
behavior and a temperature dependent prefactor. The local activation energy is slightly
increasing for higher amount of PEO and slightly decreasing for higher amount of
PDADMATFSI. The results show that PDADMATFSI has a more beneficial effect on
the local Li dynamics in comparison to PEO, as it hinders Li motion to a lesser extent.
[1] G. B. Appetecchi, G. T. Kim, M. Montanino, M. Carewska, R. Marcilla, D.
Mecerreyes, I. De Meatza, Journal of Power Sources 2010, 195, 3668-3675.
[2] S. Jeremias, M. Kunze, S. Passerini, M. Schönhoff, J Phys Chem B 2013, 117,
10596.
[3] M. Gouverneur, S. Jeremias, M. Schönhoff, Electrochim. Acta 2015, asap article.
[4] R. Bhandary, M. Schönhoff, Electrochim. Acta 2015, 174, 753-761.
216 Mixtures / Metabolomics / Fragment-based Drug Design
Application of 1H-NMR-Spektroscopy for analysis
of the geographical origin of Hazelnuts
R. Bachmann1, T. Hackl2, M. Fischer3
Rene Bachmann, [email protected]
1, 2 Institute of Organic Chemistry / Hamburg School of Food Science, University of
Hamburg
3 Hamburg School of Food Science, University of Hamburg, Germany
In view of the increasing globalization and the growing interest in locally produced
products, the analysis of the origin of food becomes more and more important. Today
turkey is the largest hazelnut producer with about 75% of world production. [1] Given
the fact that the production conditions and the qualitative marketing of the second
largest producer country Italy differ significantly, a unique opportunity for proof of
origin would be desirable. In this study different hazelnut samples from Turkey, Italy,
Georgia and Germany were analyzed by 1H-NMR-spectroscopy and the multivariate
data analysis methods PCA and PLS-DA. The PCA showed a good separation of the
samples, whereat the Georgian samples differed significantly from the Italian and
German samples. In the next step a discriminant analysis was done, which shows the
totally separation of the samples by their origin. For the validation of the results a
model was built that relate the rest of the samples to their origin-countries. It was
found that 54 of 56 samples were correctly assigned. From these results it appears that
the PCA and PLS-DA in conjunction with the 1H-NMR-Spectroscopy are good and
fast tools for determining the geographical origin of hazelnuts.
[1] J. Jannick, R. E. Paul; The Encyclopedia of Fruit and Nuts, CABI, Oxfordshire,
2008
Identification of Plasma Metabolites Prognostic of
Acute Kidney Injury after Cardiac Surgery with
Cardiopulmonary Bypass
H.U. Zacharias1, J. Hochrein2, F.C. Vogl3, G. Schley4, F. Mayer5, C. Jeleazcov6,
K.-U. Eckardt7, C. Willam8, P.J. Oefner9, W. Gronwald10
Wolfram Gronwald, [email protected]
1-3, 9, 10 Institute of Functional Genomics, University of Regensburg, Regensburg,
Germany
4, 7, 8 Department of Nephrology and Hypertension, University of ErlangenNuremberg, Erlangen, Germany
5, 6 Department of Anaesthesiology, University of Erlangen-Nuremberg, Erlangen,
Germany
Acute kidney injury (AKI) is a frequent complication following cardiac surgery with
cardiopulmonary bypass (CPB), occurring in up to 40% of cases. Postoperative AKI is
associated with an increased risk of mortality, exceeding 50% in those requiring
dialysis, morbidity and a prolonged stay in intensive care, but early detection of
postoperative AKI remains challenging. Protein biomarkers like NGAL predict AKI
excellently in homogenous cohorts, but are less reliable in patients suffering from
various co-morbidities. Therefore, we employed NMR spectroscopy in a prospective
study of 85 adult cardiac surgery patients to identify metabolites prognostic of AKI in
plasma specimens collected 24 hours after surgery [1]. Postoperative AKI of stages 13 developed in 33 cases. A Random Forests classifier trained on the NMR data
prognosticated AKI across all stages with an average accuracy of 80 ± 0.9% and an
area under the receiver-operating characteristic curve of 0.87 ± 0.01. Prognostications
were based, on average, on 24 ± 2.8 spectral features. Among the set of discriminative
ions and molecules identified were Mg2+, lactate and the glucuronide conjugate of
propofol. Using creatinine, Mg2+ and lactate levels to derive an AKIN index score we
found AKIN 1 disease to be largely indistinguishable from patients without AKI in
concordance with the rather mild nature of AKIN 1 disease.
[1] H.U. Zacharias, J. Hochrein, F.C. Vogl, G. Schley, F. Mayer, C. Jeleazcov, K.U.
Eckardt, C. Willam, P.J. Oefner, and W. Gronwald. J Proteome Res. (2015) published
ahead of print DOI: 10.1021/acs.jproteome.5b00219
Profiling metabolic changes in tumor metabolism
P. Schwarzfischer1, M. Schmidt2, D. Kube3, L. Dimitrova4, K. Kleo5, M. Hummel6,
K. Dettmer7, P. Oefner8, W. Gronwald9
Philipp Schwarzfischer, [email protected]
1, 7-9 Institute of Functional Genomics, University of Regensburg
2, 3 Department of Hematology and Oncology, University Medical Center Göttingen
4-6 Institute of Pathology, Charité-Universitätsmedizin Berlin
7-9 Institute of Functional Genomics, University of Regensburg
The link between cancer and metabolism was observed in early days of cancer
research by Otto Heinrich Warburg (known as the Warburg effect), but recently
altered metabolism has been acknowledged as one of the key hallmarks of
cancerogenesis. In metabolomic studies, the comprehensive analysis of both, the
abundance of metabolites and their rate of turnover through biochemical pathways, are
investigated. The ability of measuring a snapshot of the current global metabolomic
state of a cancer cell demonstrates its great power in the field of oncology and allows
deep insights into cellular processes within cancer cells.
We are interested in differentiating Burkitt lymphoma (BL) and diffuse large B-cell
lymphoma (DLBCL) via targeted and untargeted metabolic profiling. Both, BL and
DLBCL, belong to the class of mature aggressive B-cell lymphoma. The proper
discrimination between BL and DLBCL is important due to different treatment
strategies in adult patients. Cell culture supernatants and cell pellets as well as human
tissue samples of different BL and DLBCL entities are analyzed by nuclear magnetic
resonance spectroscopy and hyphenated mass spectrometry [1,2]. With this approach,
we gain novel insights into differences of the tumor metabolism of BL and DLBCL.
Identified pathways will be followed by combining metabolic information with
additional proteomic data generated by means of SWATH-MS/MS [3].
[1] H.U. Zacharias, J. Hochrein, M.S. Klein, C. Samol, P.J. Oefner and W. Gronwald,
Curr.Metabol., 1 (2013), 253–268.
[2] H. Kaspar, K. Dettmer, W. Gronwald and P.J. Oefner, Advances in amino acid
analysis, Anal.Bioanal.Chem., 393 (2) (2009), 445–452.
[3] L.C. Gillet, Navarro P., Tate S., Röst H., Selevsek N, Reiter L., Bonner R.,
Aebersold R., Mol. Cell Proteomics, 11 (6) (2012)
Novel strategy for the identification of
(food-)metabolites by correlation of HPLC/MSand NMR-Spectra (3DCC)
A. Bollen1, M. Fischer2, B. Meyer3, T. Hackl4
Anke Bollen, [email protected]
1, 4 Institute of Organic Chemistry / Hamburg School of Food Science, University of
Hamburg
2 Hamburg School of Food Science, University of Hamburg
3 Institute of Organic Chemistry, University of Hamburg
The high amount of Metabolites in the Metabolome makes it difficult to separate them
chromatographically and this culminates in the problem to identify single components.
Therefor the three-dimensional cross correlation (3DCC), first introduced by
BEHNKEN ET AL., is a powerful tool for non-targeted Metabolome Analysis. [1]
3DCC combines the advantages of MS and NMR and dissects NMR spectra of a
mixture into spectra of single components without fully separating the single
compounds from each other.
So far the 3DCC application was only used to analyze mixtures of glycanes. This
work will expand the application to other compounds in particular metabolites from
asparagus.
The method requires a HPLC run from an asparagus-extract to achieve partial
separation. The extract is fractionated, following and recording the whole run by mass
spectrometry. The chromatographic profile of individual metabolites is followed by
their extracted ion chromatograms (EICs).
Each fraction of the LC run is submitted to a single 1H-NMR measurement. Plotting
the chemical shift against elution time thus generates profiles of NMR signals
corresponding to their elution in the chromatographic step. Those profiles are called
extracted delta chromatograms (EDCs) analogously to the EICs from the MS spectra.
Using the fact of compounds occurring at the same retention time in the MS and NMR
allows to calculate their correlation and to deconvolve the NMR-Spectra
mathematically to spectra of only one single compound.
[1] H. N. Behnken, M. Fellenberg, M. P. Koetzler, R. Jirmann, T. Nagel, B. Meyer,
Anal. Bioanal. Chem. (2012), 404, 1427-1437.
Metabolic changes during cellular senescence
investigated by NMR spectroscopy
C. Windler1, C. Gey2, D.H. Rapoport3, K. Seeger4
Karsten Seeger, [email protected]
1,4 Institute of Chemistry, University of Lübeck, Lübeck, Germany
2 Institute of Biology and Institute of Physiology, University of Lübeck, Lübeck,
Germany
3 Fraunhofer EMB, Lübeck, Germany
Cellular senescence is an important tumor suppression mechanism and contributes to
organismic ageing. Senescent cells are characterized by a stable arrest of proliferation
but they are still metabolically active and influence neighboring cells and tissues. An
untargeted metabolomic approach using NMR spectroscopy identified increased
glycerophosphocholine level as a metabolic marker for senescence in the human
embryonic lung fibroblast cell line WI-38. These changes in metabolism are
independent of the trigger [1]. The alterations in choline metabolism emphasize the
role of senescence in tumor suppression as they are opposed to the well-known
changes in malignant cells.
We extended our study and investigated whether the metabolic changes can also be
observed in other cell types. Primary human skin fibroblasts, melanocytes and
keratinocytes have been cultured until they reached replicative senescence. Metabolic
profiles of cell extract have been determined by NMR spectroscopy showing
differences not only between the different cell types but also according to metabolic
changes due to senescence. To relate the amounts of metabolites to intracellular
concentrations, we currently determine the cell volumes.
[1] Gey C, Seeger K. Metabolic changes during cellular senescence investigated by
proton NMR-spectroscopy. Mech Ageing Dev (2013), 134, 130-138.
221 Small Molecules / Solution State Methods
Still shimming or already measuring? –
Quantitative reaction monitoring for small
molecules on the subminute timescale by NMR
J. Kind1, C.M. Thiele2
Jonas Kind, [email protected]
1, 2 Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technische
In order to enable monitoring fast reactions Zangger et al. presented a scheme for
NMR experiments with continuous data acquisition, without interscan delays, using a
spatially-selective and frequency-shifted excitation approach.[1] This allows
acquisition of 1H spectra with temporal resolutions on the ms timescale. Such
resolutions are desired in the case of reaction monitoring (RM) using stopped flow
setups. In 1H spectra without spatial selection the line width increase for a given shim
setting with changes in sample properties as magnetic field homogeneity is disturbed.
Concerning RM this is unfortunate as after injection of a reactant into a sample,
shimming prior to acquisition is necessary to obtain narrow signals. As even
automatic shim routines may last up to minutes, fast reactions can hardly be monitored
without dead times in a single stopped flow experiment.
Besides temporal resolution, a benefit of the spatially-selective and frequency-shifted
continuous NMR experiment arising from spatially-selective excitation is a reduced
effect of magnetic field inhomogeneties on the line shapes as pointed out by Freeman
and demonstrated by Zangger.[1,2]
We present the utilization of this technique for RM of small molecules where
chemical conversion and longitudinal relaxation occur on the same timescale. By
means of the alkaline ethyl acetate hydrolysis, we show advantages of spatiallyselective excitation on both temporal resolution and line shapes in stopped flow
experiments. Results were compared with data obtained by non-selective small angle
excitation experiments.
[1] G. E. Wagner, W. Bermel, K. Zangger; Chem. Commun. 2013, (49), 3155-3157.
[2] A. Bax, R. Freeman; J. Mag. Reson. 1980, 37 (1), 177-181.
Slice-Selective NMR Spectroscopy as Versatile
Tool for Chemists
M. John1, A.-C. Pöppler2, T. Niklas3, D. Stalke4
Michael John, [email protected]
1, 3, 4 Institut für Anorganische Chemie, Georg-August-Universität, Göttingen,
Germany
2 Solid-state NMR, Department of Physics, University of Warwick, UK
Slice-selecive excitation (SSE) is fundamental to MRI, pure-shift NMR and singlescan 2D NMR, but may also be used to simply obtain local NMR spectra of
“chemical” samples. For sensitive nuclei (1H, 7Li, 19F or 31P), a series of 20 spectra of
individual 1-mm-slices is obtained in <2 min using standard HR-NMR equipment.
A first application of SSE-NMR was to study the swelling of cross-linked polymers in
deuterated solvents [1,2]. Mapping the 2H quadrupolar splitting allows to assess the
homogeneity of the gel and thus its suitability as alignment medium. Furthermore,
signal integration provides local concentrations and thus detailed information about
the diffusion of solvent or additional solutes. We have recently extended the study to
ethyl/butyl acrylate, highly promising new alignment media for polar solvents and
solutes. Use of a RAFT (reversible addition-fragmentation chain transfer) agent leads
to homogeneous gels within significantly shorter swelling times.
Recently, we introduced two more applications: a “single-shot” NMR titration, where
the concentration of the titrated component follows a gradient over the sample rather
than being incremented in steps, and a “single-shot” reaction monitoring, where two
reaction components diffuse towards each other within the rf coil [3]. The latter
experiment showed the build-up and decay of a reaction intermediate at the reaction
front.
Currently, we apply SSE-NMR to mixtures in gel matrices in order to separate the
components due to their molecular size or polarity, as an alternative to the DOSY
method.
[1] A.-C. Pöppler, S. Frischkorn, D. Stalke, M. John, ChemPhysChem (2013), 14(13),
3103-3107.
[2] P. Trigo-Mouriňo, C. Merle, M.R.M. Koos, B. Luy, R.R. Gil, Chem. Eur. J.
(2013), 19(22), 7013-7019.
[3] T. Niklas, D. Stalke, M. John, Chem. Commun. (2015), 51, 1275-1277.
Detection of fast exchangeable unpaired imino
protons in RNA with chemical exchange
saturation transfer experiments
N. Kubatova1, B. Fürtig2, A. Cherepanov3, C. Richter4, H. Schwalbe5
Nina Kubatova, [email protected]
1-5 Institute for Organic Chemistry and Chemical Biology, BMRZ, Goethe University
In recent years the chemical exchange saturation transfer (CEST) experiment has
become well established for the detection of the usually invisible fast exchangeable
protons [1,2]. This approach is based on the magnetization transfer between
selectively saturated protons and water protons. The detection of the protons of
interest occurs indirectly as a modulation of the water signal [3]. As the MRI studies
were performed mainly in vivo using a variety of proteins [4] and DNAs [5], the aim
of this work is to apply the CEST method to RNA and detect the rapidly exchangeable
imino protons of unpaired nucleotides. The CEST experiments were applied to GTP
as a model for unpaired flexible nucleobase and 14mer cUUCGg-tetraloop RNA [6].
The completed saturation conditions were controlled by continuous wave irradiation
power and irradiation duration. The free GTP imino protons as well as unpaired imino
proton of U7 nucleotide in 14mer RNA demonstrate the direct CEST effect
dependence of the irradiation power. Also the temperature dependence of the CEST
effect enhancement as well as the corresponding effect on the linewidth of 14mer
RNA imino protons were detected and compared with results for GTP imino protons.
Due to the flexibility of the RNA loop at 310 K one can observe not only the imino
signal of unpaired nucleotide U7 but also imino signals from U6 from the loop and G1
at the beginning of the stem. Finally the influence of the paramagnetic relaxation
agent Cu2+-EDTA complex on the relaxation parameters and the corresponding
efficiency of the CEST experiment were analyzed.
[1] S.D. Wolff, R.S. Balaban, J. Magn. Reson. (1990), 86, 164–169.
[2] P.C.M. van Zijl, N.N. Yadav, Magn. Reson. Med. (2011), 65, 927–48.
[3] J. Zhou, et al., Prog. Nucl. Magn. Reson. Spectrosc. (2006), 48, 109–136.
[4] D. Sherry, M. Woods, Annu. Rev. Biomed. Eng. (2008) 10, 391–411.
[5] J.I. Friedman, et al., J. Am. Chem. Soc. (2010) 132, 1813–5.
[6] B. Fürtig, et al., J. Biomol. NMR, (2004), 28, 69–79.
Investigation of a threefold photochromic System
with in situ irradiation and online NMR
J. Kind1, M. Leyendecker2, C.M. Thiele3
Martin Leyendecker, [email protected]
1-3 Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technische
Photochromic compounds like azobenzenes are widely used for the synthesis of
stimuli responsive materials which are capable of changing their physical properties
reversibly upon irradiation with light. Using light sensitive materials offers high
spatial and temporal control of the stimulus required for the induced change in the
properties. Typically UV/Vis measurements are used to examine absorption
wavelengths of photoisomers in photochromic systems. NMR spectroscopy as a
complementary method can give information on the structure and the distribution of
different species of the photochromic system.
Here we show the capabilities of online NMR with in situ irradiation for the
investigation of the photochromic properties of a compound containing three
azobenzene moieties. Irradiation of the sample was applied in situ by using high
power LEDs and a waveguide.[1] Four different photoisomeres (ttt (all-trans), ttc, tcc
and ccc (all-cis)) where identified. The evolution of the distribution upon irradiation of
the stable ttt-isomer as well as the distribution of all photoisomers in a photo
stationary state where examined by using 1H-NMR spectroscopy. In addition thermal
and light-induced relaxation were observed and could directly be monitored. The
composition can be tuned by irradiation with light of the corresponding wavelength.
By using fast ASAP-HSQC[2] and real time BIRD decoupled HSQC[3] experiments
13
C chemical shifts for all different photoisomers can be obtained.
[1] H. B. C. Feldmeier, E. Riedle, R.M. Gschwind; J. Magn. Reson. 2013, 232, 39–44.
[2] D. Schulze-Sünninghausen, J. Becker,B. Luy; J. Am. Chem. Soc. 2014, 136 (4),
1242-1245.
[3] L. Paudel, R. W. Adams, P. Király, J. A. Aguilar, M. Foroozandeh, M. J. Cliff, M.
Nilsson, P. Sándor, J. P. Waltho,G. A. Morris; Angew. Chem. Int. Ed. 2013, 52 (44),
11616-11619.
Supramolecular lyotropic liquid cristalline phases
as alignment media
M. Leyendecker1, N.-C. Meyer2, C.M. Thiele3
Martin Leyendecker, [email protected]
1-3 Clemens-Schöpf Institut für Organische Chemie, Technische Universität
Benzene-1,3,5-tricarboxyamides (BTAs) are known to self-assemble into rod like and
helical supramolecules.[1] These stiff aggregates act as mesogenes to form
thermotropic or lyotropic liquid crystals.[2,3] Aggregates of achiral substituted BTAs
form racemic mixtures of (M)- and (P)-helices. Introduction of enantiopure side
chains leads to helices with only one handedness.[4]
Determining the conformation or relative configuration of small organic molecules is
not always possible via 3J-couplings or NOE data. Weak orienting media give access
to residual dipolar couplings (RDCs) which offer complementary information. RDCs
provide angular and distance information with respect to the external magnetic field.
To achieve anisotropic conditions lyotropic liquid crystals (LLCs) are used as so
called alignment media. For structure determination of small organic molecules the
LLCs should be compatible with organic solvents and introduce only a low degree of
order.[5] Chiral alignment media can transfer the chiral information to the analyte.
Enantiomers interact differently with chiral alignment media and can therefore be
differentiated.[6]
In this work several BTAs were synthesized and tested for their LLC behavior. We
could show that BTAs with achiral and chiral side chains form LLCs in organic
solvents. To investigate the capability of BTA-LLCs as alignment media, analytes
were added to the phases. By fitting the obtained RDCs to structure proposals, the
structures of the analytes could be confirmed. This demonstrates BTA-LLCs can be
used as alignment media for organic compounds.
[1] S. Cantekin, T. de Greef, A. Palmans, Chem. Soc. Rev. (2012), 41, 6125–6137.
[2] Y. Matsunaga, N. Miyajima, Y. Nakayasu, Bull. Chem. Soc. Jpn. (1988), 61, 207.
[3] D. Wang, Y. Huang, J. Li, Chem. Eur. J. (2013), 19, 685–690.
[4] M. Smulders, A. Schenning, E. Meijer, J. Am. Chem. Soc. (2008), 130, 606-611.
[5] B. Böttcher, C. M. Thiele, eMagRes (2012), 1, 169-180.
[6] M. Sarfati, P. Lesot, D. Merlet, J. Courtieu, Chem. Comm. (2000), 21, 2069-2081.
15
N NMR Spectroscopy in Coordination Chemistry
W. Baumann1, C. Kubis2, D. Thomas3, M. Horstmann4
Wolfgang Baumann, [email protected]
1-4 Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Rostock, Germany
Phosphorus(III) compounds have a rich and well-developed coordination chemistry
and are widely used in technical applications including homogeneous catalysis. This is
not only due to their favourable and useful properties but most likely driven by the
fact that 31P NMR is a helpful, straightforward and readily applicable research tool in
this area of chemistry for decades.
Other Group 5 compounds, among them such with nitrogen as donor atom, have a
similarly rich chemistry but NMR is still rarely developped as a tool characterize
coordination compounds or to estimate their chemical and physical properties [1].
This is remarkable, because modern but nowadays standard experiments, particularly
indirect detection of the insensitive nitrogen nucleus by other, more sensitive nuclei
(hydrogen or even phosphorus [2]) make the determination of nitrogen NMR
parameters much easier compared to former times.
This contribution intends to promote the use of 15N NMR in coordination chemistry.
For that purpose, examples from zirconium, ruthenium and rhodium chemistry will be
presented.
[1] A recent exception: A. Requet, O. Colin, F. Bourdreux, S. M. Salim, S. Marque, C.
Thomassigny, C. Greck, J. Farjon, D. Prim, Magn. Reson. Chem. (2014), 52, 273-278.
[2] L. Carlton, R. Weber, Magn. Reson. Chem. (1997), 35, 817-820
A new polyglutamic acid based alignment medium
for NMR spectroscopy of small organic molecules
S. Hansmann1, C.M. Thiele2
Stefanie Hansmann, [email protected]
1-2 Clemens-Schöpf Institut für Organische Chemie und Biochemie, Technische
Universität Darmstadt, Germany.
RDCs being anisotropic NMR parameters demand a partial orientation of the analyte
with respect to the magnetic field. This can be realized using lyotropic liquid
crystalline phases. If the alignment medium is chiral, diastereomorphous interactions
lead to different orientations of enantiomers [1]. Helical homopolypeptides like PBLG
(poly-γ-benzyl-L-glutamate) and PELG (poly-γ-ethyl-L-glutamate) have already been
used as alignment media, but improvements in enantiodiscriminating effects would be
desirable [2,3].
Therefore a new side chain modified polyglutamic acid has been synthesized via ring
opening polymerisation of highly purified N-carboxyanhydride. Implementation of an
additional chiral center in the side chain is supposed to increase the desired
enantiodiscrimination. Synthesis and characterization of the polymer and alignment
properties including enantiodiscrimination investigated will be presented.
[1] M. Sarfati, P. Lesot, D. Merlet, J. Courtieu, Chemical Communications (2000),
2069-2081.
[2] A. Marx, V. Schmidts, C. M. Thiele, Magn. Reson. Chem. (2009), 47, 734-740.
[3] C. Aroulanda, M. Sarfati, J. Courtieu, P. Lesot, D. Merlot, Chem. Eur. J. (2009),
15, 254-260.
Quality of NMR Spectra Assignments and Standards for
Scientific Publications: Concepts and Free Software Tools
to Improve Analysis of Small Organic Compounds and
Workflows in Academic NMR Facilities
S. Kuhn1, J.C. Liermann2, N.E. Schlörer3
Nils Schlörer, [email protected]
1 Department of Computer Science, University of Leicester
2 NMR facility, Institute of Organic Chemistry, Johannes Gutenberg University
Mainz
3 NMR facility, Department of Chemistry, University of Cologne
Prior to publication of NMR data in scientific journals, a considerable effort is
required to assure reliability and scientific soundness of the published data. Recently,
the use of unassigned 1D NMR data and insufficient exploitation of information from
2D experiments have become a widespread practice in the area of synthetic organic
chemistry. Thus, incomplete or erroneous assignments are frequently found in
published NMR data nowadays, even if quality of primary data is high.
To foster more reliable ‘publication ethics’ in this area, joint efforts from synthetic
chemists, spectroscopists, and editorial boards are required. As a first step in that
direction, the free nmrshiftdb2 software on one hand provides a QuickCheck tool
which allows spectroscopists to faster oversee the quality of assignments generated by
users and can also be utilized for educational aspects in NMR spectroscopy. On the
other hand, a local NMR database and a LIMS for laboratory management can be set
up to establish a more efficient workflow from raw data to the final spectra
assignments.
In a coordinated project of several academic NMR service laboratories, a concept for
optimized data treatment has been developed (and is under constant revision) which
includes all steps from placing the order for a sample’s analysis through semiautomated assignment and assignment quality control to the final output for
publication.[1]
[1] S. Kuhn and N.E. Schlörer, Magn. Reson. Chem. (2015), doi: 10.1002/mrc.4263.
Regulation of Quadrupolar Splittings in NMR
Experiments on Anisotropic Samples
S. Weißheit1, J. Ilgen2, A. Beimel3, R. Kümmerle4, P. Lendi5, R. Hensel6, D. Moskau7,
V. Schmidts8, C.M. Thiele9
Susann Weißheit, [email protected]
1-3, 8, 9 Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry,
Technische Universität Darmstadt, Darmstadt, Germany
4 -7 Bruker BioSpin AG, Fällanden, Switzerland
It is known that the quadrupolar splitting of solvent resonances is directly linked to the
orientational properties of an analyte in NMR alignment media like lyotropic liquid
crystals or gels, [1-4] and is fairly sensitive to temperature changes. For well studied
systems like PBLG, the magnitude of the splitting can even be used as a measure of
sample composition, homogeneity and stability. For reliable measurement of
anisotropic NMR parameters, the control of the quadrupolar splitting is essential.
Therefore we propose to use the recently developed “NMR Thermometer” [5] as a
means to lock on a split solvent signal and regulate this splitting by varying the
temperature. This enables the comparison of different samples or experiments all
scaled to the same strength of the orientational interaction of an analyte in an
alignment medium.
Herein we show that the PBLG as established alignment medium for small molecules
in organic solvents is suitable to be used with the NMR Thermometer and the
reproducibility of anisotropic sample conditions. Temperature profiles were measured
and the response to temperature steps was examined. Furthermore it is shown that it is
possible to set the quadrupolar splitting to predefined values in various experimental
and sample conditions.
As application we measure RDCs of a rigid organic small molecule (IPC). The
obtained results show reproducibility of enantiodiscrimination of (‒) and (+)-IPC in
PBLG, we thus propose the quadrupolar splitting is useful to regulate anisotropic
sample conditions in combination with the NMR-Thermometer.
[1] B. Böttcher, C. M. Thiele, eMagRes. 2012, 1, 169–180.
[2] A. Marx, B. Böttcher, C. M. Thiele, Chem. Eur. J. 2010, 16, 1656-1663.
[3] A. Marx, C. M. Thiele, Chem. Eur. J. 2009, 15, 254-260.
[4] Z. Luz, R. Poupko, E. T. Samulski, J. Chem. Phys. 1981, 74, 5825-5837.
[5] F. Schumann, Bruker Users Meeting, 2012.
Desktop NMR spectroscopy for quality control and
reaction monitoring
K. Singh1, E. Danieli2, B. Blümich3
Bernhard Blümich, [email protected]
1-3 Institut für Technische und Makromolekulare Chemie, RWTH Aachen University,
Aachen, Germany
Chemical reaction kinetics can be followed in real time by NMR spectroscopy when
passing the reaction mixture through the magnet and acquiring spectra in stopped or
continuous flow mode. Due to shorter feed lines, desktop NMR spectrometers [1]
provide better time resolution than high-field NMR spectrometers. We report kinetic
studies of variety of chemical reactions with time-resolved single-shot 1H NMR
spectroscopy including first studies on the kinetic isotope effect, which aims at
understanding the chemically selective signature of deuterium depletion in different
crude oils [2-3] as this effect reports on the evolution of the earth over a time range of
up to 150 million years. The variation in reaction rate with changing isotope ratio at
the reaction site provides information about the primary isotope effect of the reaction,
which also depends on temperature and pressure. Compact 1H and 19F NMR
spectroscopy is implemented to study the temperature dependence of the reaction rate
constant for the hydrolysis of acetic anhydride and ethyl trifluoroacetate in H2O, D2O
and D2O/H2O mixtures. The first order rate constants have been determined in the
readily available temperature range from 278 K to 326 K in an effort to understand the
effect of temperature on the kinetic isotope effect and the activation energy. The
observed ratio kD2O/kH2O < 0.5 of the reaction rate constants kD2O and kH2O reveals that
both reactions exhibit a primary kinetic isotope effect but different temperature
dependency for both of the reactions [4].
[1] B. Blümich, S. Haber-Pohlmeier, and W. Zia, Compact NMR, de Gruyter, Berlin,
2011.
[2] A. L. Sessions, S. P. Sylva, R. E. Summons, and J. M. Hayes, Geochim.
Cosmochim. Acta. (2004), 68, 1545-1559.
[3] S. C. George, C. J. Boreham, S. A. Minifie, and S. C. Teerman, Org. Geochem.
(2002), 33, 1293-1317.
[4] B. Rossall, and R. E. Robertson, Can. J. Chem. (1975), 539, 869-877.
Understanding the origin of the selectivity of the
organocatalyzed enantioselective acylation of
1,2-alkane diols
A. Kolmer1, M. Köberle2, M. Fredersdorf3, A.-C. Pöppler4, C.E. Müller5,
P.R. Schreiner6, C.M. Thiele7
Mira Köberle, [email protected]
1-3, 7 Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische
4 Current address: The University of Warwick, Department of Physics, Coventry, UK
5, 6 Institut für Organische Chemie, Justus-Liebig-Universität Giessen, Giessen,
Germany
The tetrapeptide Boc-L-(π-Me)-His-AGly-L-Cha-L-Phe-OMe (AGly represents γaminoadamantanecarboxylic acid) is a highly effective enantioselective organocatalyst
for the monoacylation of trans-cycloalkane-1,2-diols [1,2]. To understand the
observed selectivity, quantum chemical calculations were performed [1-3], but thus
far neither experimental evidence regarding the existence of the key intermediate nor a
solution structure of the tetrapeptide itself is available. Here we present our
investigation on the solution structure of the tetrapeptide by NMR spectroscopy.
Since computations suggest some conformational flexibility of the organocatalyst, it is
difficult to determine the three-dimensional structure with routine procedures. To gain
insight on the conformational landscape, both NOE [4] and RDC [5] have been used
recently. Using a combined analysis of quantitative NOE/ROE and RDC data, we
were able to determine an ensemble of conformers whose structure agrees with the
proposed mechanism. Using a mixture of tetrapeptide and diol, we were able to detect
and evaluate several intermolecular NOE contacts. These contacts also are in good
agreement with the proposed mechanism.
Thus, using a combined NOE/ROE and RDC analysis, we were able to determine the
origin of the selectivity of a highly flexible organocatalyst.
[1] C. E. Müller, et al., Angew. Chem. Int. Ed. (2008), 47, 6180–6183.
[2] C. E. Müller, et al., J. Org. Chem. (2013), 78, 8465–8484.
[3] C. B. Shinisha, R. B. Sunoj, Org. Lett. (2009), 11, 3242–3245.
[4] C. P. Butts, C. R. Jones, J. N. Harvey, Chem. Commun. (2011), 47, 1193–1195.
[5] B. Böttcher, C. M. Thiele, in Encyclopedia of Magnetic Resonance (2012), John
Wiley & Sons, Ltd.
Conformational analysis of an antibiotic
cyclodepsipeptide
M. Fredersdorf1, M. Kurz2, L. Lannes3, C. Rigling4, M.-O. Ebert5, C.M. Thiele6
Maic Fredersdorf, [email protected]
1, 2 Sanofi-Aventis Deutschland GmbH, R&D-LGCR-Chemistry, Frankfurt am Main,
Germany
3 Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt,
4, 5 Department of Chemistry and Applied Biosciences, ETH Zürich, Switzerland
6 Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technische
Griselimycin[1,2] as well as Methylgriselimycin are cyclic depsipeptides which are
composed of ten amino acids. The structural difference between these two peptides is
the presence of L-trans-4-methylproline (Methylgriselimycin) instead of L-proline
(Griselimycin) at position 8 in the amino acid sequence. This tiny variation involves
some major anti-bacterial advantages over Griselimycin. To get a deeper insight in the
structure-activity relationship we determined the conformations of Methylgriselimycin
in CDCl3 using nuclear Overhauser effect (NOE) distance measurements. Furthermore
we prepared anisotropic NMR samples to get access to residual dipolar couplings
(RDCs) which contain in contrast to NOE data alone “global” structural information
of the aligned molecule. The obtained RDC constraints are used in a subsequent
refinement process of the previously NOE-derived structural ensemble.[3-5]
[1] Bull. Soc. Chim. Fr. 1971, 6, 2363-2365
[2] Mol. Conform. Biol. Interact. 1991, 611-625
[3] ChemBioChem 2005, 6, 1672-1678
[4] J. Mol. Struc. 2013, 1036, 298-304
[5] J. Pept. Sci. 2014, 20, 901-907
Photo-Induced Lipid Oxidation Studies by HighResolution NMR Spectroscopy
Yu.E. Moskalenko1, C.M. Marques2, M.S. Baptista3
Yulia Moskalenko, [email protected]
1 Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São
Paulo, Brazil / IMC RAS, St. Petersburg, Russia
Paulo, Brazil / Institut Charles Sadron, CNRS, Strasbourg, France
Paulo, Brazil
Lipid oxidation plays a central role in the life of the eukaryotic cells [1]. The products
of lipid oxidation, if uncontrolled, can have a deleterious effect on the functioning of
the cell, and are known to be involved in a variety of diseases. Photosensitization
reactions producing excited triplet oxygen species cause the chemical transformation
of biological tissues and have been practically employed in photo-dynamic therapy,
PDT. This work aims at understanding chemical and structural changes in
phospholipids caused by photo-induced oxidation and seen in 1H, 13C, 2H and 31P
NMR spectra.
We study mono-unsaturated phospholipids in isotropic solutions, liposome
suspensions and lamellar phases being subjected to Methylene Blue photosensitization
under red light (630 nm). We identified hydroperoxides [2] as the main products of
POPC and POPG oxidation in methanol solutions and followed the kinetics of their
formation by 1H NMR spectroscopy. 31P high-resolution NMR spectra showed, as
expected, isotropic signal for small liposomes but powder spectrum with dominating
perpendicular tensor component for lamellar phases. For the latter case 31P chemical
shift anisotropy correlates with the lipid charge but seems to be insensitive to a partial
oxidation.
This work is supported by CNPq (project PVE 400997/2014-2).
[1] B. Halliwell, and J. M. C. Gutteridge. Free radicals in biology and medicine, 4th
ed ed. Oxford University Press, Oxford, 2007.
[2] G. Weber, T. Charitat, M.S. Baptista, A.F. Uchoa, C. Pavani, H.C. Junqueira, Y.
Guo, V. Baulin, R. Itri, C.M. Marques, and Schroder A.P., Soft Matter (2014), 10,
4241-4247.
In situ NMR measurements on the formation of
Zeolithic Imidazole Frameworks
J.G. Schiffmann1, S. Springer2, L. van Wüllen3
Jan Gerrit Schiffmann, [email protected]
1 Chair for Chemical Physics and Material Science, Group of Prof. van Wüllen,
Institute of Physics, University of Augsburg, Germany
2 Group of Dr. M. Wiebcke, Institute for Inorganic Chemistry, University of
Hannover
3 Chair for Chemical Physics and Material Science, Institute of Physics, University of
Augsburg
In order to illuminate the building mechanism of meta stable compounds, the reaction
which leads to a solid zeolithic imidazole framework is studied via NMR, which
allows a series of quick measurements to follow the course of the reaction.
Solid ZIF-25 is synthesized from two solutions, one containig a Zinc cation, the other
containing a linking agent, which in our case was 1,3-Dimethylimidazole. The
formation of the ZIF occurs within hours and is being investigated by a combination
of solid and liquid state NMR measurements. In a further row of experiments, a
modulating agent is added to the solution and the change in the outcome is
investigated. Through studies of chemical shift and intensity, the course of the
reaction is studied and a hypothesized mechanism could be proven. Furthermore, the
effect of the modulating agent in the solution could be shown.
Solution Structure of 1H-Benzo-1,5-diazepines
F. Bendrath1, V. Specowius2, M. Winterberg3, W. Desens4, P. Langer5, D. Michalik6
Dirk Michalik, [email protected]
1-5 Institut für Chemie, University of Rostock, Rostock, Germany
6 Leibniz-Institut für Katalyse an der Universität Rostock, Rostock, Germany
In case of complex tautomeric systems more than two tautomers are possible. For
benzo-1,5-diazepine compounds different tautomeric forms can be discussed
(diaminodiene/enaminoimine, and cis/trans isomers). Two main and two minor
tautomeric forms could be detected and have been characterized by 1H, 13C and 15N
NMR spectroscopy. Equilibration and ratios of isomers depend on substituents and are
influenced by solvent polarity. Inversion of the diazepine ring has been investigated.
[1] F. Bendrath, V. Specowius, D. Michalik, and P. Langer, Tetrahedron, 2012, 68,
6456–6462.
[2] W. Desens, M. Winterberg, P. Langer, and D. Michalik, Tetrahedron, submitted.
Automated Structure Verification: What are the
Right Experiments and Processing?
S. Golotvin1, R. Pol2, P. Keyes3, P. Wheeler4, G. Rheinwald5
Gerd Rheinwald, [email protected]
1 ACD Moscow, Moscow, Russian Federation
2 ACD/Labs Moscow, Moscow, Russian Federation
3 Lexicon Pharmaceuticals, Princeton, NJ
4 ACD/Labs, Toronto, ON
5 ACD/Labs Germany, Frankfurt am Main
Chemical structure characterization regularly employs a variety of 2D NMR
techniques. However, past practice for the computer automation of this technique,
Automated Structure Verification (ASV), primarily employs either 1D 1H NMR only,
or a combination of 1D 1H NMR and 2D 1H-13C HSQC[1]. Recent development
makes the inclusion of a wide array of experimental data possible in fully automated
structure verification. Inclusion of expanded data types supports more accurate
structure verification, decreasing the likelihood that false structures pass through a
verification process.
Recent experimental work has provided a rich array of experimental data on a large
variety of structures for chemical samples that are derived from several sources.
Included are 1D 1H, 1D 13C, 1D 13C DEPT, 1H-13C DEPT-edited HSQC, unedited 1H13
C HSQC, COSY, TOCSY, HMBC, H2BC data. Coupling the analysis of such data
with the ability to create spectroscopically relevant challenge structures[2] enhances
the certainty of the chemist that they have synthesized the correct structure, and the
confidence with which any organization can assume that the structure of any
component in its library is completely correct.
Analysis of this variety of data sets helps to establish the most efficient experimental
processes to ensure that correct structures are rapidly recognized, while incorrect
chemically relevant structures are flagged for failure or for further analysis.
Here we present an analysis of several different correlation techniques in order to
better understand the value of various NMR experiments in ASV.
[1] P. Keyes, G. Hernandez, G. Cianchetta, J. Robinson and B. Lefebvre, Magn.
Reson. Chem. 2009, 47 (1), 38-52, 2009.
[2] S.S. Golotvin, R. Pol, R.R. Sasaki, A. Nikitina and P. Keyes, Magn. Reson. Chem.
2012, 50 (6), 429–435.
Conformational and configurational information of
(chiral) molecules determined by cross-linked,
helically-chiral poly(phenylacetylenes) as
alignment media
K. Wolf1, M. Reggelin2
Kai Wolf, [email protected]
1, 2 Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische
The determination of the conformation and the relative configuration of (small)
organic molecules by NMR in solution is at the heart of organic chemistry. Residual
dipolar couplings (RDCs), containing both distance and angle information, provide the
opportunity to extract conformational and configurational information of (chiral)
analytes. To do so, it is necessary to partially orient the analyte molecules in the
magnetic field, which can be done either by stretched polymer gels (SAG – strain
induced alignment in a gel) or lyotropic liquid crystalline phases (LLC-phase). For the
determination of absolute configurations by NMR, a necessary requirement is the use
of a chiral and non-racemic alignment medium. This may be realized by the structural
motif of a helix which is formed by amino acid-based poly(phenylacetylenes) (PPAs).
We found LLC-phases of such helically chiral PPAs to be excellent enantiodifferentiating chiral alignment media. A main drawback of such LLC-phases is the
need for minimum mesogen-concentration to reach the LLC-state which defines
minimum alignment strength. In contrast to LLCs, polymer gels provide the
opportunity to scale the orientational degree over a much wider range by diversifying
parameters like degree of crosslinking, solvent etc.
Herein we describe chiral polymer gels derived from the promising PPAs already used
in LLC-phase studies. (Co)-polymer solutions were linked by polymerisation
initiators. The obtained polymer sticks were anisotropically swollen in a standard
NMR tube and their orientational properties were investigated.
[1] G. Kummerlöwe, B. Luy, Annu. Rep. NMR Spectrosc. (2009), 68, 193-230.
[2] E. Yashima, K. Maeda, H. Iida, Y. Furusho, K. Nagai, Chem. Rev. (2009), 109,
6102-6211.
[3] A. Krupp, M. Reggelin, Magn. Reson. Chem. (2012), 50 Suppl 1, S45-52
[4] N.-C. Meyer, A. Krupp, V. Schmidts, C. M. Thiele, M. Reggelin, Angew. Chem.
(2012), 124, 8459-8463.
Aspartic acid based Polyarylacetylene as
Enantiomer Differentiating Alignment Medium
A. Proskurjakov1, M. Reggelin2
Alexander Proskurjakov, [email protected]
1, 2 Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische
The application of RDCs to solve conformational und configurational problems of
(small) organic molecules in solution is a field of NMR spectroscopy of increasing
interest [1]. A precondition for the measurements of these global anisotropic NMRparameters containing distance and angle information, is to partially orient the analyte
molecules with respect to the magnetic field. This can be done either by stretched
polymer gels (SAG – strain induced alignment in a gel) or by dissolving the analyte in
a lyotropic liquid crystalline phase (LLC-phase).
If the goal of the investigation of a chiral, non-racemic molecule is the absolute
configuration, the basic requirement is the orientation of the analyte in an
enantiodifferentiating manner, which requires the application of a chiral and uniformly
configured alignment medium. The number of chiral alignment media, compatible
with common organic NMR-solvents, is still very small [2]. Therefore, we started to
work on the development of new chiral alignment media and found helically chiral
amino acids-based poly(phenylacetylenes) [3] to be very well suited for this purpose
[4,5].
Herein we would like to describe the application of a new poly(phenylacetylene)
based on the natural amino acid aspartic acid, as chiral LLC-alignment medium.
[1] G. Kummerlöwe, B. Luy, Ann. Rep. NMR, (2009), 68, 193-230.
[2] B. Luy, J. Indian Inst. Sci., (2010), 90, 119-132.
[3] E. Yashima, K. Maeda, H. Iida, Y. Furusho, K. Nagai, Chem. Rev., (2009), 109,
6102-6211.
[4] N.-C. Meyer, A. Krupp, V. Schmidts, C. M. Thiele, M. Reggelin, Angew. Chem.
Int. Ed., (2012), 51, 8334-8338.
[5] A. Krupp, M. Reggelin, Magn. Reson. Chem., (2012), 50, 45-52.
239 Spin Dynamics / Theory
SPIDYAN - A MATLAB Library for Simulating
Pulse EPR
S. Pribitzer1, A. Doll2, T. Segawa3, G. Jeschke4
Stephan Pribitzer, [email protected]
1-4 Laboratory of Physical Chemistry, ETH Zürich, Zürich Switzerland
While short rectangular microwave pulses in pulse electron paramagnetic resonance
(EPR) spectroscopy can cover bandwidths of about 100 MHz, spectral widths of
paramagnetic transition metal complexes usually exceed 1 GHz. This limited
excitation bandwidth significantly restricts the application of pulse EPR sequences on
such compounds. With the recent advent of arbitrary waveform generators (AWG)
with sampling rates in the GS/s range it has become possible to extend the excitation
bandwidth up to and beyond 500 MHz, into the ultra-wide band (UWB) regime [1].
AWGs allow for excitation with frequency-swept pulses, which provide effective flip
angles between 0 and π. While these passage pulses are well known in NMR
spectroscopy, their effects are not yet fully understood in EPR. In need of a package
for simulation of frequency swept pulses the open-source SPIn DYnamic ANalysis
(SPIDYAN) library was developed, which runs in the MATLAB environment.
By exciting electron spin echoes with frequency swept pulses on a home-built UWB
EPR spectrometer [2], we measured electron spin echo envelope modulation
(ESEEM) spectra on single crystals of γ-irradiated malonic acid and of about 1 ppm
Cu2+ impurities in TiO2 (rutile). By recording the entire echo it is possible to correlate
the ESEEM spectrum to the EPR spectrum [3], resulting in two-dimensional spin echo
correlation spectra, which provide a higher resolution.
With this work we show that SPIDYAN can be used to simulate and investigate the
effect of frequency-swept pulses on commonly applied EPR experiments.
[1] A. Doll, M. Qi, S. Pribitzer, N. Wili, M. Yulikow, A. Godt, and G. Jeschke, Phys.
Chem. Chem. Phys. (2015) 17 (11), 7334-7344.
[2] A. Doll, and G. Jeschke, J. Magn. Reson. (2014) 246, 18-26.
[3] S. Lee, B. R. Patyal, and J. H. Freed, The Journal of Chemical Physics (1993) 98
(5), 3665-3689.
240 8. Index of Contributors Abacilar, M. .................................... 60 Abdullin, D. .................... 30, 146, 163 Abe, H. ......................................... 101 Abele, R. ....................................... 137 Abrahams, J.P. .............................. 184 Ackermann, K. ................................ 78 Aguiar, M.B. ................................... 70 Akhmetzyanov, D. ........ 164, 167, 173 Alaei, H. ....................................... 163 Albe, K. ........................................ 198 Anders, J. ........................................ 98 Anderson, E.A. ............................... 57 Aneziris, C.G. ............................... 197 Ashbrook, S.E. ................................ 68 Aslam, N. ...................................... 101 Assafa, T. ...................................... 176 Avadhut, Y.A. ............................... 177 Avrutina, O. .................................... 29 Bachmann, R. ............................... 216 Bader, K. ....................................... 175 Balbach, J. .............................. 71, 136 Baldwin, A.J. ................................ 142 Bannwarth, C. ............................... 203 Baptista, M.S. ............................... 233 Bärenwald, R. ............................... 105 Bargon, J. ...................................... 181 Baumann, A. ......................... 165, 204 Baumann, W. ................................ 226 Baumeister, U. .............................. 184 Bazin, A. ......................................... 72 Becker, S. ......................... 32, 61, 104 Behrends, J. .................................... 56 Behrens, R. ................................... 153 Beimel, A. ..................................... 229 Bell, N.G.A. .................................... 90 Bell, S. ............................................ 57 Bendel, L.E. .................................. 111 Benders, S. .................................... 155 Bendrath, F. .................................. 235 Bennati, M. .............. 39, 135, 149, 171 Bermel, W. ..................................... 91 Bernarding, J. ............................... 181 Bernatowicz, P. .............................. 83 Berndhäuser, A. .................... 147, 163 Berniger, L. .................................. 127 Bertet, P. ......................................... 54 Bertrand, H.C. .............................. 164 Bessi, I. ................................. 116, 124 Beumer, C. ..................................... 69 Bienfait, A. ..................................... 54 Biernat, J. ..................................... 130 Bignami, G.P.M. ............................ 68 Billeter, M. ................................... 143 Binas, O. ....................................... 116 Bittl, R. ..................................... 56, 79 Blackburn, J.W.T. .......................... 90 Blackledge, M. ............................... 61 Bleicken, S. .................................. 176 Bloos, D. ...................................... 100 Blümich, B. .................................. 230 Bock, J. ........................................... 35 Böckmann, A. ................................ 72 Bode, B.E. ...................................... 78 Bodenhausen, G. ............................ 31 Boffa-Balleran, T. ........................ 190 Böhm, B. ...................................... 156 Böhme, F. ..................................... 186 Bollen, A. ..................................... 219 Bommerich, U. ............................. 181 Bordignon, E. ............................... 176 Bornet, A. ....................................... 31 Bowen, A. .................................... 167 Bowen, A.M. ........................ 168, 170 Brächer, A. ................................... 153 Brachhold, N. ............................... 197 Brandt, M.S. ........................... 55, 172 Braunbeck, G. .............................. 154 Index of Contributors
241 Breeze, B.G. ................................... 36 Breitzke, H. ............ 27, 108, 198, 202 Brendler, E. .......................... 192, 197 Brinkkötter, M. ............................. 215 Brodrecht, M. ............................... 108 Brouwer, E.M. .............................. 126 Brown, S.P. .................................... 47 Brückner, S.I. ................................. 60 Brüdermann, E. ............................ 160 Brunner, E. ............................. 60, 214 Bruschewski, M. ........................... 157 Buchenberg, B. ............................... 52 Buchenberg, W. .............................. 35 Buck, J. ......................................... 145 Buhr, F. ........................................ 121 Buntkowsky, G. .. 27, 29, 83, 106, 108, 181, 198, 199, 200, 201, 202 Butts, C.P. ...................................... 94 Cadalbert, R. ................................... 72 Carlomagno, T. ............................... 37 Carnevale, D. ................................ 200 Carravetta, M. ................................. 80 Carter, E. ........................................ 66 Cekan, P. ...................................... 148 Cetiner, E.C. ................................. 134 Chatterjee, D. ............................... 137 Chaudret, B. ................................. 201 Cherepanov, A. ..................... 139, 223 Christ, N.A. .......................... 127, 138 Clabbers, M. ................................. 184 Claridge, T.D.W. ............................ 80 Cobas, C. ........................................ 94 Consentius, P. ................................. 86 Corzilius, B. ................... 82, 178, 179 Culioli, G. ....................................... 73 Cuniberti, G. ................................... 60 Dale, M.W. ..................................... 36 Damjanovic, M. .............................. 75 Danieli, E...................................... 230 Dasari, D. ..................................... 175 Dastvan, R. ................................... 126 Dawson, D.M. ................................ 68 de Groot, H.J.M. ........................... 184 Degiacomi, M.T. .......................... 142 Demay-Drouhard, P. .....................164 Demuth, D. ....................................107 Denysenkov, V...................... 164, 180 Desens, W. ....................................235 Dettmer, K. ...................................218 Dianat, A. ........................................60 Diaz, D. .........................................151 Dimitrova, L. ................................218 Dittmer, R. ....................................198 Doll, A. ................................... 59, 239 Dominguez, G. ..............................152 Donets, S. ........................................60 Dost, G. .........................................196 Dötsch, V. ............................. 120, 137 Dounas, A. ......................................59 Drescher, M. ......................... 141, 191 Drescher, S. ...................................105 D'Souza, V. .....................................80 Dubey, R.K. ..................................184 Duchardt-Ferner, E. 87, 125, 127, 129, 138 Duckett, S.B. ...................................41 Duer, M.J. .......................................46 Dumez, J.-N. ...................................80 Düsterhus, S. .................................127 Duthie, F. ........................................30 Dyakonov, V. ........................ 165, 204 Ebert, M.-O. ..................................232 Eckardt, K.-U. ...............................217 Edwards, L.J. ..................................80 Ehrenberg, H. ................................193 El-Mkami, H. ..................................77 Enders, M. .......................................75 Endeward, B. ........ 117, 120, 150, 164 Englert, S. .......................................29 Entian, K.-D. .................................127 Erlenbach, N. ................................117 Ernst, M. .........................................95 Esteve, D. ........................................54 Farès, C. ..........................................76 Fatkullin, N. ....................................65 Fedorczyk, B. ..................................83 Ferreira, T.M. ................................105 Index of Contributors
242 Finkler, A. ..................................... 175 Fischer, M. ............................ 216, 219 Florin, N. ........................................ 30 Foroozandeh, M. ............................. 92 Fredersdorf, M. ..................... 231, 232 Freudenhammer, D. ...................... 156 Friedlaender, S. ............................. 158 Frost, D. ........................................ 190 Frydel, J. ......................................... 83 Fuchs, M. ........................................ 76 Fujara, F. ........................... 64, 65, 211 Fürstner, A. ..................................... 76 Fürtig, B. .. 58, 87, 109, 114, 115, 118, 131, 145, 223 Gande, S.L. ................................... 137 García-Sáez, A.J. .......................... 176 Gardiennet, C. ................................. 72 Gaudet, R. ..................................... 138 Geist, L. ........................................ 143 Georgiev, D. ................................... 57 Gerstmann, U. ................................. 96 Gey, C. .......................................... 220 Geyer, A. ........................................ 60 Giachetti, A. .................................... 61 Giannoulis, A. ................................. 78 Giller, K. ................................. 32, 104 Giraudeau, P. .................................. 80 Glaenzer, J. ................................... 144 Glaser, S.J. ........................ 43, 93, 161 Glaubitz, C. ..................................... 38 Godt, A. .................. 59, 141, 166, 176 Gohlke, U. ...................................... 86 Golitsyn, Y. .................................. 195 Golotvin, S. ................................... 236 Goodwin, D.L. ................................ 80 Gophane, D.B. .............. 110, 117, 159 Goradia, N. ................................... 132 Goretzki, B. .................................. 138 Görlach, M. ................................... 132 Gouilleux, B. .................................. 80 Gouverneur, M. ...................... 53, 215 Graham, M.C. ................................. 90 Gränz, M. ...................................... 159 Gratteri, P. .................................... 111 Graziadei, A. .................................. 37 Green, B.L. ..................................... 36 Gremer, L. ...................................... 69 Grey, C.P. ............................... 34, 188 Griesinger, C. ................................. 61 Grimm, S. ..................................... 145 Grimme, S. ................................... 203 Groh, M. ....................................... 214 Grohe, K. ........................................ 32 Grohmann, D. ............................... 113 Gronwald, W. ....................... 217, 218 Groß, A. ....................................... 141 Groszewicz, P.B. .................. 198, 202 Gröting, M. ................................... 198 Gruber, T. ..................................... 136 Grundmann, S. ............... 52, 156, 157 Grünewald, C. .............................. 168 Grüninger, H. ............................... 190 Grytz, C.M. .......................... 133, 148 Güntert, P. .................................... 133 Gupta, K.B.S.S. ............................ 184 Gupta, P. ......................................... 76 Guthausen, G. ......................... 63, 213 Gutiérrez, R. ................................... 60 Gutmann, T. ..... 29, 83, 106, 108, 181, 199, 200, 201, 202 Haaks, M. ............................. 196, 209 Haarmann, F. ................................ 183 Hacker, C. .................................... 127 Hackl, T. ............................... 216, 219 Hagelueken, G. ............... 30, 144, 146 Hajjaj, B. ........................................ 57 Halbmair, K. ................................. 171 Hansman, G. ................................. 152 Hansmann, S. ............................... 227 Hantke, K. .................................... 129 Hasse, H. ...................................... 153 Haugland, M. .................................. 57 Havenith, M. ................................ 160 Heckel, A. .................................... 116 Hehn, M. ........................................ 62 Heilemann, M. .............................. 131 Heinemann, S.H. .......................... 132 Index of Contributors
243 Heise, H. ................................. 69, 182 Hellmich, U.A. ..................... 127, 138 Helmling, C. ........... 58, 110, 114, 134 Hempel, G. ..................................... 49 Hengesbach, M. .............. 58, 114, 131 Henker, J. ..................................... 111 Hennig, J. ....................................... 35 Hensel, R. ..................................... 229 Herbst, C. ..................................... 132 Hett, T. ................................. 163, 169 Hetzke, T.F.B. .............................. 168 Hiller, F. ....................................... 145 Hiller, W. ........................................ 62 Hintz, H. ....................................... 166 Hintze, C. ..................................... 191 Hochrein, J. .................................. 217 Hofele, R. ..................................... 130 Hofmann, M. .............. 64, 65, 71, 119 Höger, S. ...................................... 203 Holldack, K. ................................... 99 Höllthaler, P. ................................ 131 Horn, M. ....................................... 151 Horstmann, M. ............................. 226 Hoyer, W. ............................... 69, 182 Hrubesch, F.M. ............................. 172 Hulme, A.N. ................................... 57 Hummel, M. ................................. 218 Hutchison, M.-T. .......................... 123 Ilgen, J. ......................................... 229 Imai, S. ........................................... 80 Imhof, T. ........................................ 91 Immel, S. ........................................ 73 Indris, S. ....................................... 193 Isoya, J. .................................. 36, 101 Itkis, D.M. .................................... 192 Jager, W.F. ................................... 184 Jaipuria, G. ................................... 104 Jannin, S. ........................................ 31 Jantschke, A. .................................. 60 Jaremko, L. ................................... 130 Jaremko, M. .................................. 130 Jassoy, J.J. .................................... 147 Jaumann, E. .................................. 120 Jeleazcov, C. ................................. 217 Jeschke, G. ................ 59, 72, 166, 239 Jha, S. ............................................121 Ji, X. ...............................................31 Jo, W. ............................................198 John, M. ........................................222 Jonker, H.R.A. ..... 110, 115, 116, 122, 123, 124 Jung, B. ..................................... 35, 52 Kadavath, H. .................................130 Kalbitzer, H.R. ................................70 Kallies, W. ....................................161 Kaltschnee, L. .................................91 Kappert, F. ....................................112 Karg, B. .........................................140 Kartaschew, K. ..............................160 Kasanmascheff, M. ............... 135, 149 Kaushik, M. .......................... 178, 179 Kazemi, S. .....................................133 Keller, H. .......................... 58, 87, 125 Keller, K. ......................................166 Kemnitz, E. ...................................185 Kemnitzer, T.W. ...........................177 Keyes, P. .......................................236 Keyhani, S. .............................. 58, 114 Kind, J. .................................. 221, 224 Kirchhain, H. ................................206 Kiyandokht, R. ................................60 Klama, F. ........................................61 Klare, J. .........................................113 Kleinkauf, A. ................................154 Kleo, K. .........................................218 Klose, D. .......................................113 Knapp, M. .....................................193 Köberle, M. ...................................231 Köck, M. .........................................73 Köckenberger, W. ...........................81 Koetter, P. .....................................127 Kolmar, H. ......................................29 Kolmer, A. ....................................231 Komar, A.A. .................................121 König, A. ................................ 69, 197 Konrat, R.......................................143 Kopp, J. ...........................................53 Index of Contributors
244 Korneev, S. ................................... 113 Kossman, S. .................................. 149 Koźmiński, W. .............................. 143 Kraffert, F. ...................................... 56 Kremer, W. ..................................... 70 Kresse, B. ................................. 64, 65 Kreutz, C. ..................................... 125 Krupp, A. ........................................ 73 Krushelnitsky, A. ............ 71, 119, 136 Kuballa, T. ...................................... 88 Kubatova, N. ................................. 223 Kube, D. ....................................... 218 Kubis, C. ....................................... 226 Kubo, Y. ......................................... 54 Kudlinzki, D. ........................ 112, 137 Kuhn, S. ........................................ 228 Kulminskaya, N. ............................. 32 Kultaeva, A. .................................. 158 Kumar, S. ...................................... 130 Kümmerle, R. ............................... 229 Kunert, B. ....................................... 72 Kunjir, N. ...................................... 173 Kuprov, I. ....................................... 80 Kurz, M. ....................................... 232 Kurzbach, D. ................................. 143 Kutz, F. ......................................... 121 Kwan, A. ......................................... 32 Lacabanne, D. ................................. 72 Lachenmeier, D.W. ......................... 88 Lafon, O. ....................................... 200 Laguerre, A. .................................. 120 Langer, P. ..................................... 235 Lannert, M. ................................... 210 Lannes, L. ............................. 128, 232 Lapinaite, A. ................................... 37 Lappan, U. .................................... 194 Ławniczak, P. ............................... 106 Lee, W. ................................. 135, 149 Lego, D. ........................................ 181 Lehmkuhl, S. ................................ 155 Lehner, F. ..................................... 139 Lemke, E.A. .................................. 113 Lendi, P. ....................................... 229 Leskes, M. .................................... 188 Leutzsch, M. ................................... 76 Levitt, M.H. .................................... 40 Leyendecker, M.................... 224, 225 Li, W. ........................................... 199 Liermann, J.C. .............................. 228 Linhard, V. ................................... 137 Link, S. ................................... 71, 136 Linser, R. ................................ 32, 104 Lips, K. ......................................... 174 Liu, J. ........................................... 202 Liu, Z............................................ 206 Lockhauserbäumer, J. ................... 152 Loll, B. ........................................... 86 López Valentín, J. ........................ 189 Lorenz, R. ....................................... 35 Love, J. ......................................... 204 Lovett, J.E. ..................................... 57 Luchinat, C. .................................... 61 Ludwig, U. ..................................... 35 Luy, B. ..................................... 74, 93 Mallagaray, A. .............................. 152 Mammoli, D. .................................. 31 Mandelkow, E. ............................. 130 Marchanka, A. ................................ 37 Marko, A. ..................... 133, 148, 173 Marques, C.M. ............................. 233 Martin, S.W. ......................... 196, 209 Marx, R. ....................................... 100 Matsuoka, H. ........................ 163, 203 Mayer, F. ...................................... 217 Mecking, S. .................................. 191 Meggers, E. .................................. 111 Meier, B.H................................ 72, 95 Meier, C. ........................................ 56 Menza, M. ...................................... 35 Meyer, A. ..................................... 163 Meyer, B. ..................................... 219 Meyer, N.-C. ................................ 225 Michalchuk, A.A.L. ....................... 90 Michalik, D. ................................. 235 Michan, A.L. ................................ 188 Micke, P. ........................................ 49 Milani, J. ........................................ 31 Index of Contributors
245 Mirus, O. ...................................... 126 Mittelstaet, J. ................................ 121 Moelmer, K. ................................... 54 Mordvinkin, A. ............................. 186 Morris, G.A. ............................. 42, 92 Morris, R.E. .................................... 68 Morton, J.J.L. ................................. 54 Möser, J. ....................................... 174 Moskalenko, Yu.E. ................. 91, 233 Moskau, D. ................................... 229 Motylenko, M. .............................. 192 Müller, A.J. .................................. 213 Müller, C.E. .................................. 231 Müller, H. ....................................... 69 Munari, F. ....................................... 61 Muñoz, J. ........................................ 73 Murphy, D.M. ................................ 66 Murray, L. ...................................... 90 Nair, D.G. ....................................... 70 Narayanan, S.P. .............................. 70 Nasiri, A.H. .................................. 129 Nasu. D. ......................................... 29 Natividad-Tietz, S. ....................... 151 Naumova, A. ................................ 189 Ndukwe, I.E. .................................. 94 Neese, F. ............................... 149, 203 Nehrkorn, J. .................................... 99 NejatyJahromy, Y. ................ 163, 169 Neugebauer, P. ............................. 100 Neuhaus, D. .................................... 26 Neumann, P. ......................... 101, 175 Neundorf, I. .................................. 151 Newton, M.E. ................................. 36 Nguyen, T.-Q. .............................. 204 Nick, T.U. ............................. 135, 149 Niesteruk, A. ........................ 122, 123 Niklas, T. ...................................... 222 Nilsson, M. ............................... 89, 92 Nizamutdinova, A. ....................... 207 Noeske, J. ..................................... 145 Norman, D.G. ................................. 77 Odell, B. ......................................... 80 Oeckinghaus, T............................. 175 Oefner, P. ..................................... 218 Oefner, P.J. ...................................217 Ohlenschläger, O. .........................132 Ollila, O.H.S. ................................105 Onoda, S. ................................ 36, 101 Orbán-Németh, Z. .........................143 Orru, R. .........................................184 Oshima, T. .............................. 36, 101 Osiewacz, H.D. .............................137 Ott, M. ...........................................189 Otto, M. .........................................197 Özen, M.B. ...................... 63, 212, 213 Paasch, S. ......................................214 Paciok, E. ......................................155 Palacios, J.K. .................................213 Pankiewicz, R. ..............................106 Parigi, G. .........................................61 Passias, D. .......................................87 Pérez-Castells, J. ...........................152 Peters, T. .......................................152 Petrov, O. ......................................196 Pfender, M. ...................................101 Philippot, K. ..................................201 Piechatzek, T. ..................................69 Pla, J.J. ............................................54 Plackmeyer, J. ....................... 164, 170 Platzer, G. .....................................143 Plaumann, M. ................................181 Plog, A. .........................................199 Poeppl, A. .....................................158 Pogorzelec-Glasser, K. ..................106 Pol, R. ...........................................236 Policar, C. .....................................164 Polshettiwar, V..............................200 Polyhach, Y. ....................................59 Pöppler, A.-C. ....................... 222, 231 Pospiech, H. ..................................132 Pribitzer, S. ............................. 59, 239 Prisner, T.F. . 117, 120, 126, 133, 148, 150, 159, 164, 167, 168, 170, 173, 180 Pritisanac, I. ..................................142 Privalov, A.F. ............................ 64, 65 Proskurjakov, A. ...........................238 Index of Contributors
246 Pulka-Ziach, K. ............................... 91 Qi, M. ..................... 59, 141, 166, 176 Qureshi, N.S. ........................ 110, 115 Rachocki, A. ................................. 106 Rajca, A. ....................................... 176 Ramachandran, R. ......................... 132 Räntzsch, V. .......................... 212, 213 Rapoport, D.H. ............................. 220 Ratajczyk, T. ................................... 83 Ratzsch, K.-F. ................. 63, 212, 213 Rauls, E. ......................................... 96 Ravichandran, K. .......................... 149 Rech, B. ........................................ 174 Reggelin, M. ................... 73, 237, 238 Reichart, F. ................................... 151 Reinhard, F. .................................. 154 Reinsperger, T. ............................... 93 Retegan, M. .................................. 203 Reuhl, M. ...................................... 208 Reutter, S. ..................................... 211 Rezaei-Ghaleh, N. ........................... 61 Rheinwald, G. ............................... 236 Rhode, M. ..................................... 193 Richter, C. .... 109, 110, 112, 116, 122, 124, 223 Richter, D. ............................ 178, 179 Rigling, C. .................................... 232 Risse, T. .................................. 86, 162 Robson, S. ....................................... 80 Röck, L. ........................................ 203 Rödel, J. ........................................ 198 Rodnina, M.V. .............................. 121 Rogov, V.V. .................................. 137 Rohrmüller, M. ............................... 96 Rombouts, J. ................................. 184 Ronneburg, H. .............................. 162 Roos, M. ................... 49, 71, 119, 136 Rößler, E.A. ........ 64, 65, 71, 119, 177 Rostas, A.M. ................................. 160 Rothe, M. ...................................... 136 Rothermel, N. ....................... 201, 202 Rouger, L. ....................................... 80 Rovó, P. .......................................... 32 Ruck, M. ....................................... 214 Saalwächter, K. 49, 71, 119, 136, 186, 187, 189, 195 Sapper, E. ..................................... 198 Sattig, M. ...................................... 208 Sauer, G. ................................ 29, 181 Saxena, K. ............................ 112, 137 Saxena, S. ..................................... 143 Scalise, V. .................................... 185 Schaal, D. ....................................... 70 Scheffler, M. ................................ 101 Scheler, U. .............................. 48, 194 Schenkel, T. .................................... 54 Scheuermann, M. ......................... 193 Schieborr, U. ................................ 137 Schiemann, O. .. 28, 30, 146, 147, 163, 169, 203 Schiffer, H.-P. .............................. 157 Schiffmann, J.G. ........................... 234 Schilling, F. .................................... 93 Schleicher, E. ............................... 160 Schleiff, E..................................... 126 Schley, G. ..................................... 217 Schlörer, N.E. ............................... 228 Schmidt, M. .......................... 197, 218 Schmidt, W.G. ................................ 96 Schmidts, V. ................................. 229 Schnegg, A. ............................ 99, 174 Schneider, G.J. ............................. 195 Schnorr, K. ................................... 110 Scholz, G. ..................................... 185 Schölzel, D. .................................... 69 Schönhoff, M. ........................ 53, 215 Schöps, P. ..................... 167, 170, 173 Schreiner, P.R. ............................. 231 Schubert E. ................................... 169 Schubert, E. .................................. 163 Schuetz, D. ................................... 126 Schütze, F. .................................... 191 Schwalbe, H. .... 58, 87, 109, 110, 111, 112, 114, 115, 116, 121, 122, 123, 124, 128, 131, 134, 137, 139, 145, 179, 223 Schwarzfischer, P. ........................ 218 Index of Contributors
247 Schwarzinger, S. ............................. 70 Sebastião, P. ................................. 215 Sederman, A.J. ............................... 51 Seeger, K. ..................................... 220 Segawa, T. .................................... 239 Senker, J. .............................. 177, 190 Sergeev, A. ................................... 192 Seymour, V.R. ................................ 68 Shaykhalishahi, H. ........................ 182 Siegel, R. ...................................... 190 Sigurdsson, S.Th. 110, 117, 133, 148, 159, 173 Silvers, R. ............................. 109, 123 Simenas, M. .................................. 158 Simon, B. ........................................ 37 Simpson, R. ............................ 52, 156 Singh, K. ...................................... 230 Sinnaeve, D. ................................... 92 Smolarkiewicz, I. .......................... 106 Sochor, F. ....................... 58, 109, 114 Soetbeer, J. ..................................... 59 Sood, R. ........................................ 105 Specowius, V. ............................... 235 Sperlich, A. ........................... 165, 204 Spindler, P.E. ........................ 167, 170 Springer, S. ................................... 234 Sreeramulu, S. ...... 112, 122, 123, 137 Stalke, D. ...................................... 222 Stehle, T. .............................. 122, 123 Steinert, H.S. .................... 58, 87, 145 Steinhoff, H.-J. ............................. 113 Stevens, M.A. ................................. 77 Steyrleuthner, R. ............................. 56 Stoll, S. ........................................... 99 Stubbe, J. .............................. 135, 149 Suckow, M. .................................. 186 Sumiya, H. .................................... 101 Suvorina, S. .................................. 113 Takahashi, S. .................................. 97 Takeda, K. ...................................... 95 Tepper, K...................................... 130 Terradot, L. ..................................... 72 Thankamony, A.S. ........ 108, 200, 202 Thevarpadam, J. ........................... 116 Thiel, W. .........................................76 Thiele, C.M. ... 91, 221, 224, 225, 227, 229, 231, 232 Thomas, B. ....................................184 Thomas, D. ....................................226 Thommen, M. ...............................121 Tietze, D. ........................................29 Tkach, I. ........................................171 Trantzschel, T. ..............................181 Trautmann, C. ...............................211 Tritt-Goc, J. ...................................106 Tropea, C. ............................... 52, 156 Trusov, L.A. ..................................192 Trutschel, M.-L. ............................187 Tvingstedt, K. ...............................204 Uhrín, D. .........................................90 Uluca, B. ................................. 69, 182 Un, S. ............................................164 Urlaub, H. .....................................130 Utrecht, C. .....................................152 Vaca Chávez, F. ............................215 Valera, S. ........................................78 van Slageren, J. .............................100 van Wüllen, L. . 53, 67, 205, 206, 207, 234 Vasa, S.K. .......................................32 Väth, S. ................................. 165, 204 Vaverka, J. ....................................100 Venkatachalam, S. ........ 205, 206, 207 Vincent Ching, H.Y. .....................164 Vion, D. ..........................................54 Vizgalov, V.A. ..............................192 Vogel, M. ...... 107, 168, 196, 208, 209 Vogl, F.C. .....................................217 von Harbou, E. ..............................153 Vuichoud, B. ...................................31 Vyalikh, E. ....................................192 Wacker, A. ............................ 110, 145 Waclawska, I. ........................ 120, 150 Wagner, D. ....................................179 Wagner, G. ......................................80 Waltho, J.P. .....................................84 Warhaut, S. ...................................131 Index of Contributors
248 Wassermann, F. .............................. 52 Weber, S. ...................................... 160 Wegner, J. ..................................... 166 Weickhmann, A.K. ............... 125, 129 Weirich, F. ...................................... 69 Weiskopf, N. ................................... 50 Weissbach, S. ................................ 152 Weißheit, S. .................................. 229 Weisz, K. ...................................... 140 Weiz, A. ........................................ 214 Welderufael, Z.T. ............................ 80 Wenzel, S. ....................................... 70 Werner, J.M. ................................... 80 Werner, M..................................... 108 Wessling, M. ................................. 155 Wheatley, P.S. ................................ 68 Wheeler, P. ................................... 236 Wiedemann, C. ............................. 132 Wiegand, T. .................................... 72 Wiese, M. ..................................... 155 Wiesner, B. ................................... 194 Wilhelm, M. .................... 63, 212, 213 Wili, N. ........................................... 59 Willam, C. .................................... 217 Williamson, P.T.F. .......................... 80 Windler, C. ................................... 220 Winterberg, M. ............................. 235 Wirmer-Bartoschek, J........... 111, 123 Wittmann, J. ................................... 95 Wöhnert, J. ...... 87, 125, 127, 129, 137 Wolf, K. ....................................... 237 Wolf, L.M. ..................................... 76 Wolter, A.C. ................................. 129 Wrachtrup, J. ........................ 101, 175 Wurm, J.P. .................................... 137 Wüstemann, J. .............................. 181 Xiang, S. ......................................... 32 Xu, Y. ........................................... 202 Yulikov, M. ............................ 72, 166 Zacharias, H.U. ............................ 217 Zappe, A. ...................................... 175 Zawadzka-Kazimierczuk, A. ........ 143 Żerko, S. ....................................... 143 Zetzsche, H. .................................. 118 Zhang, H. ..................................... 176 Zhang, K. ............................. 199, 202 Zhao, L. ........................ 106, 199, 202 Zhou, X. ......................................... 54 Zick, K. ........................................ 193 Ziegler, C. ............................ 120, 150 Zweckstetter, M......... 61, 85, 104, 130 Index of Contributors

Book of Abstracts - Chemie - Technische Universität Darmstadt

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