Abstract Session Viewer

PQ

Code: PQ	Time Slot/Poster Number: 316	Session: Solids: Methods, Poster
Ultrafast SIMPSON as Stand-Alone Program or Implemented on Modern High-Performance Computing Facilities
Zdenek Tosner; Rasmus Andersen; Thomas Vosegaard; Niels Chr. Nielsen
Interdisciplinary Nanoscience Center, Aarhus, Denmark
Abstract
An ultrafast version of SIMPSON as a stand-alone program or implemented on high-performance computing facilities is introduced for simulations without solid- and liquid-state NMR spectroscopy. The speed of the highly-cited SIMPSON open-source program is increased by orders of magnitude through incorporation of efficient numerical procedures and refined variants of, e.g., gamma-compute. The program is further enhanced through efficient use on stand-alone multiple-processor computer, computer clusters, and grids for computers using a minimum intrusion grid protocol. The underlying principles, architectures is described in combinations with examples including challenging solid-state NMR and optimal control design examples.

Code: PQ	Time Slot/Poster Number: 317	Session: Solids: Methods, Poster
Dynamics in Membrane-Bound Peptides in Flipped- and Unflipped Bicelles and Bilayers. Unified Representation of Spectra for Oriented Samples
Kresten Bertelsen; Sara Krogh Hansen; Niels Chr. Nielsen; Thomas Vosegaard
Center for Insoluble Protein Structures, Aarhus, Denmark
Abstract
We investigate the effect of the dynamics of the membrane anchoring of membrane-bound peptides in the analysis of oriented-sample solid-state NMR experiments. The overall dynamics depend strongly on the lipid system which needs be isolated to study the membrane dynamics within the lipids. We use a spectral representation compensated for the bilayer/bicelle order parameter to compare the spectra of the peptides in different lipid systems.

Code: PQ	Time Slot/Poster Number: 318	Session: Solids: Methods, Poster
Digital Concepts in Building of NMR Relaxometers and Their Advantages in Study of Natural Polysacccharides
Leonid Grunin¹; Dmitry Karasev¹; Ekaterina Nikol'skaya¹; John Edwards²; Ivan Kalashnikov¹; Yrij Grunin¹; Innokenty Nikolaev¹; Natalia Celisheva¹
¹Mari State Technical University, Yoshkar-Ola, Russian Federation; ²Process NMR Associates LLC, Danbury, CT
Abstract
An NMR relaxometer based on FPGA technology was built with digital generation of RF pulses and acquisition of relaxation data that has allowed a significant improvement of the NMR measurement quality. The proton NMR lineshapes of polysaccharides were fit to a specific model allowing a nearly exact approximation. Spin-spin and spin-lattice relaxation of several different polysaccharides were investigated to observe the effect of their different physical and chemical properties. The techniques developed can help to estimate the structural properties of polymers such as crystallinity, surface area, domain size, and pore distribution.

Code: PQ	Time Slot/Poster Number: 319	Session: Solids: Methods, Poster
Determination of Relative Tensor Orientations by γ-Encoded Chemical Shift Anisotropy/Heteronuclear Dipolar Coupling 3D NMR Spectroscopy in Biological Solids
Guangjin Hou^{1, 2}; Sivakumar Paramasivam¹; In-Ja L. Byeon^{2, 3}; Jinwoo Ahn^{2, 3}; Angela M. Gronenborn^{2, 3}; Tatyana Polenova^{1, 2}
¹University of Delaware, Newark, DE; ²Pittsburgh Center for HIV Protein Interactions, Pittsburgh, PA; ³University of Pittsburgh School of Medicine, Pittsburgh, PA
Abstract
Although the magnitudes of the three principal elements of CSA tensor can be measured easily with previously developed techniques, there is no direct information about the orientation of the CSA tensor in the molecular frame. In this work, we propose a new three-dimensional NMR approach based on R-type symmetry sequences, which reintroduces dipolar and CSA interactions in t1 and t2 indirect dimensions, respectively. The orientational sensitivity of the CSA/DIP pattern is demonstrated theoretically and experimentally. The present approach works at moderate magic angle spinning frequencies (10-20 kHz) and allows simultaneous measurement of multiple sites of interest. The NMR experiments are carried out on [15N]-N-acetyle-valine and N-formyl-Met-Leu-Phe tripeptide.

Code: PQ	Time Slot/Poster Number: 320	Session: Solids: Methods, Poster
Analysis of pulse errors and artifacts in spin I=1 T1Q measurements
Xiang Ma; Gregory Boutis
Brooklyn College of The City University of New Yor, Brooklyn , NY
Abstract
The quadrupolar relaxation time, T1Q, is a sensitive probe for investigating motions ranging from 10 MHz to 1 Hz in solid and semi-solid spin ensembles. In these experiments special caution must be taken for undesirable double- and single-quantum coherences. In practice, one may suppress unwanted quantum coherences in T1Q measurements by proper phase cycling. In this work we performed an experimental and simulation based study of the efficiency of a phase cycling scheme in suppressing unwanted quantum coherences in T1Q measurements. Our simulation work quantifies the performance of a phase cycling scheme as a function of finite pulse width effects, pulse phase errors, Zeeman and RF field inhomogeneity, pulse flip errors and RF pulse transients.

Code: PQ	Time Slot/Poster Number: 321	Session: Solids: Methods, Poster
13C Solid-State NMR Chromatography: 1H T1 Relaxation Ordered Spectroscopy under Magic Angle Spinning
Yusuke Nishiyama¹; Michael Frey²; Sseziwa Mukasa²; Hiroaki Utsumi¹
¹JEOL Ltd., Tokyo, Japan; ²JEOL USA, INC, Peabody, MA
Abstract
A simple and practical method to separate the 13C NMR spectra of solid mixtures is introduced. The 1H longitudinal (T1) relaxation time is used to separate the overlapping 13C chemical shift spectra of solid mixtures. In the present presentation, we propose a practical procedure and conditions for the separation based on 1H T1. The resulting 2D spectrum of the mixture contains separate 13C spectra for each component of the mixture that are identical to 13C spectra of the isolated materials. We call this procedure relaxation ordered spectroscopy (ROSY). The ROSY method is demonstrated on a mixture of two disaccharides and on a commercial drug containing several compounds.

Code: PQ	Time Slot/Poster Number: 322	Session: Solids: Methods, Poster
Through-Bond Chemical Shift Correlation NMR Spectroscopy with Indirect Detection in Fast Rotating Solids
Kanmi Mao; Marek Pruski
Ames Laboratory, Iowa State University, Ames, IA
Abstract
Two-dimensional through-bond 1H{13C} solid-state NMR experiments utilizing fast MAS, indirect detection and homonuclear multipulse 1H decoupling are presented. Remarkable efficiency of polarization transfer was achieved at MAS rates exceeding 40 kHz. A simple procedure for optimization of 1H homonuclear decoupling sequences under these conditions is demonstrated. The capabilities of these techniques were confirmed on two naturally abundant solids, tripeptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (f-MLF-OH) and brown coal.

Code: PQ	Time Slot/Poster Number: 323	Session: Solids: Methods, Poster
Magic Angle Turning Phase Adjusted Sideband Separation (MATPASS) Experiment
Ivan Hung; Zhehong Gan
NHMFL, Tallahassee, FL
Abstract
A magic-angle turning phase-adjusted sideband separation (MATPASS) experiment is presented. The experiment combines the advantages of linear t1 increments of MAT and simple data processing of PASS for separating spinning sideband manifolds.

Code: PQ	Time Slot/Poster Number: 324	Session: Solids: Methods, Poster
NMR Detected Stark-induced Equilibria of Quadrupolar Nuclei
Matthew Tarasek; James G. Kempf
Rensselaer Polytechnic Institute, Troy, NY
Abstract
Radiofrequency E fields at 2w0 can induce DQ transitions in quadrupolar nuclei. Exploration of these effects is of interest to aid understanding of electrical response in NMR parameters. This in turn may be used to characterize internal E fields in molecular or material contexts. The mechanism of the DQ transitions is a quadrupolar Stark effect that results when an E field distorts the local electronic environment. This alters components (V2q) of the field-gradient tensor. When the E field oscillates at 2w0, the V2q follow suit, rendering otherwise nonsecular quadrupolar terms as static 1st-order observables. As a first demonstration, we utilize 2w0 effects to measure the quadrupolar Stark tuning rate of 69Ga in GaAs at room temperature and 14.1 T.

Code: PQ	Time Slot/Poster Number: 325	Session: Solids: Methods, Poster
Sensitivity enhancement in solid state NMR of aligned membrane proteins
Gopinath Tata; Nathaniel Traaseth; Raffaello Verardi; Kaustubh Mote; Gianluigi Veglia
University of Minnesota, Minneapolis, MN
Abstract
Sensitivity enhancement (SE) methods represented a significant breakthrough in liquid state NMR and to some extent in MAS solid state NMR. Here we propose SE methods for SLF and HETCOR experiments in static solid state NMR. In these experiments SE up to 40% is obtained. We also propose 3D SE-HETCOR-SLF experiments. Remarkably, in a 3D experiment (3D PISEMAI-HETCOR) where we combine SE with polarization inversion, a resultant sensitivity enhancement up to 180% can be achieved. The efficacy of these methods is demonstrated on a membrane protein. These new methods will make it possible the rapid data acquisition of multidimensional experiments for proteins oriented in magnetically and mechanically aligned lipid membranes as well as liquid crystalline materials.

Code: PQ	Time Slot/Poster Number: 326	Session: Solids: Methods, Poster
Proton NMR and spin relaxation in systems with magnetic nanoparticles. Effects of particle size and solvent viscosity
Natalia Noginova¹; Aleksandr Andreyev²; Joseph Hall¹
¹NSU, Norfolk, VA; ²Virginia Tech, Blacksburg, VA
Abstract
To better understand the specifics of nuclear magnetic resonance and spin relaxation in systems with magnetic nanoparticles and test the limits of the outer sphere model for the diffusion related relaxation, iron oxide nanoparticle suspensions are studied in the dependence of the particle concentration, size and solvent viscosity. Frames of the model are estimated and the applicability of fast-motion and fast-diffusion approximations is discussed for large effective sizes and limiting molecular motion cases.

Code: PQ	Time Slot/Poster Number: 327	Session: Solids: Methods, Poster
SSNMR characterization of new organic compounds and copper complexes of polymeric structures.
Ana Karina Chattah¹; Juan Manuel Lázaro Martínez²; Gustavo Alberto Monti¹; Graciela Yolanda Buldain²; Viviana Campo d'all Orto²
¹FaMAF, Argentina, Argentina; ²Facultad de Farmacia y Bioquímica, Buenos Aires, Argentina
Abstract
We applied advanced NMR techniques in solid state to study organic compounds and novel copper complexes of polyampholyte and polyelectrolyte polymeric structures. Remarkably, the copper-polyampholyte complex acts as an efficient heterogeneous catalyst for H2O2 activation and the degradation of Methyl Orange. Using 2D 1H-13C WISE NMR and proton spin-lattice relaxation times in the laboratory and rotating frame (TH1 and TH1ρ), we analyzed the non-homogenous character of the doped and undoped materials. The effect of the paramagnetic ion in the structure of the polymers was also elucidated through these experiments. Additionally, 13C CP-MAS, 1H-13C HETCOR, and solution NMR spectra allowed us to conclude that the 2-carboxaldehydeimidazole molecule differed in the solution and in the solid-state after its synthetic process.

Code: PQ	Time Slot/Poster Number: 328	Session: Solids: Methods, Poster
Measurement of hetero-nuclear distances using a symmetry-based pulse sequence in solid-state NMR
Jean Paul Amoureux¹; Lei Chen²; Bingwen Hu¹; Olivier Lafon¹; Julien Trebosc¹; Feng Deng²; Qiang Wang¹
¹Universite De Lille, Villeneuve D'ascq, France; ²Chinese Academy of Sciences, Wuhan, China
Abstract
We have developed two simple and robust double resonance experiments for measuring heteronuclear distances. Our methods can be applied not only to pairs of spin-1/2 nuclei (S-REDOR) but also to spin systems including one quadrupolar nucleus (S-RESPDOR). Our sequences are insensitive to: rf-field inhomogeneity, homonuclear dipolar interactions, CSA and offset and they are not dipolar truncated. These advantages thus allow measuring 13C/14,15N internuclear distances in fully 13C labeled biomolecules, even in case of long distances in multiple-spin systems. One additional great advantage is that internuclear distances, involving or not one quadrupolar nucleus, can be determined by using an analytical expression.

Code: PQ	Time Slot/Poster Number: 329	Session: Solids: Methods, Poster
Hetero- and Homonuclear Dipolar Recoupling Without 1H Decoupling
Anders Bodholt Nielsen¹; Morten Bjerring¹; Lasse Arnt Straasø¹; Andrew Nieuwkoop²; Chad Rienstra²; Zdenek Tosner¹; Niels Chr. Nielsen¹
¹Interdisciplinary Nanoscience Center, Aarhus, Denmark; ²University of Illinois, Champaign, Illinois
Abstract
We present novel recoupling strategies based on exponentially modulated rf fields, which through appropriate amplitude and phase combinations enable establishment of universal solutions for hetero- as well as homo-nuclear dipolar recoupling without decoupling. The methods are easy to adjust for ultimate broadband behavior, robustness towards inhomogeneous rf fields, slow and fast sample spinning, or band-selective coherence transfer. The methods – referred to as EXPonentially mOdulated Recoupling Techniques (EXPORT) - are intrinsically γ-encoded and allows for incorporation of COMB β-compensation. We demonstrate the performance of hetero- and homonuclear EXPORT recoupling without decoupling analytically, numerically, and experimentally on uniformly 13C,15N-labelled samples of GB1 and ubiquitin.

Code: PQ	Time Slot/Poster Number: 330	Session: Solids: Methods, Poster
Solid-State NMR Spectroscopy of Nano-mole Concentration of Membrane Proteins : Use of a Copper-Chelated-Lipid Speeds Up Data Collection
Kazutoshi Yamamoto; Jiadi Xu; Ayyalusamy Ramamoorthy
The University of Michigan, Ann Arbor, Ann Arbor, MI
Abstract
Atomic-level structure and dynamics are essential to understand the function of membrane proteins and for the development of compounds to potentially treat related diseases. Recent studies have demonstrated that solid-state NMR techniques are promising. However some of the key difficulties that limit the high throughput applications of solid-state NMR techniques are: large amount of sample requirement, a long data collection, and RF-induced sample heating. Therefore, the development of new approaches to speed up solid-state NMR measurements is essential. In this presentation, we will demonstrate the use of a copper-chelated lipid to significantly enhance the sensitivity of solid-state NMR experiments on lipid bilayers under either aligned static or unaligned magic angle spinning experimental conditions.

Code: PQ	Time Slot/Poster Number: 331	Session: Solids: Methods, Poster
Structure determination of membrane proteins: a case study of proteorhodopsin
Evelyn Lake; Lichi Shi; Meaghan Ward; Evelyn Lake; Mumdooh Ahmed; Leonid Brown; Vladimir Ladizhansky
University of Guelph, Guelph, Canada
Abstract
Magic angle spinning solid state NMR has great potential for studying membrane in their native environment. We have recently initiated studies of a 27 kDa (238 aa) integral membrane proton pump proteorhodopsin (PR), and assigned ~80% of its transmembrane residues. In this abstract we present further structural and dynamic studies of PR with particular emphasis on the solid state NMR methodology. We will discuss (i) proton-detected chemical shift correlation experiments in perdeuterated back exchanged PR, and their potential for the assignment and characterization of the flexible loops and termini; (ii) Measurements of internuclear restraints, and difficulties with assigning proton driven spin diffusion (PDSD) spectra; (iii) Measurements of paramagnetic relaxation enhancements and their use for resolving ambiguity of the PDSD spectra.

Code: PQ	Time Slot/Poster Number: 332	Session: Solids: Methods, Poster
Distance Determination in Amyloid Fibrils with DNP-Enhanced MAS Solid State NMR Spectroscopy
Galia Debelouchina¹; Marvin Bayro¹; Melanie Rosay²; Patrick van der Wel⁵; Geoffrey Platt³; Anthony Fitzpatrick⁴; Shane Pawsey²; Sheena Radford³; Christopher Dobson⁴; Werner Maas²; Robert Griffin¹
¹Massachusetts Institute of Technology, Cambridge, MA; ²Bruker BioSpin Corporation, Billerica, MA; ³Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK; ⁴University of Cambridge, Cambridge, UK; ⁵University of Pittsburgh School of Medicine, Pittsburgh, PA
Abstract
We use DNP-enhanced correlation spectroscopy at 9 T and 100 K to determine structurally relevant distances in amyloid fibrils formed by GNNQQNY, TTR(105-115), and full-length β-2-microglobulin. In each of these cases, the effect of temperature on the molecular conformation of the peptide or the protein will be evaluated and the influence of dynamics on the resolution of the DNP-enhanced spectra will be discussed. The performance of commonly used solid-state NMR experiments like PDSD, TEDOR, REDOR and DQ-DRAWS will be compared to room temperature data. This comparison demonstrates that DNP-enhanced correlation spectroscopy can be used to collect high quality structural data and novel information regarding the intermolecular arrangement of the monomers in the TTR(105-115) and β-2-microglobulin fibrils will be presented.

Code: PQ	Time Slot/Poster Number: 333	Session: Solids: Methods, Poster
Cryogenic Temperature Effects and Resolution of a Microcrystalline Protein Preparation in Solid State NMR
Arne Linden¹; W. Trent Franks²; Umit Akbey²; Barth-Jan van Rossum²; Hartmut Oschkinat¹
¹SFB 449, Freie Universität, Berlin, Berlin; ²Leibniz-Institut für molekulare Pharmakologie, FMP, Berlin, Berlin
Abstract
We investigate the alpha-spectrin SH3 domain with Magic angle spinning solid state NMR at cryogen temperatures by slow cooling, because NMR-timescale protein dynamics are not fully understood at low temperatures. Single resonances were tracked to 210K and three different types can be distinguished: Some resonances broaden and split up in several signals and therefore disappear. Other signals remain unchanged in their NMR-signals and in the aromatic region some peaks are only detectable at low temperatures. The coalescing behavior depends upon the solvent accessibility and backbone dynamics specific to each individual residue. At temperatures down to 95K all NMR-signals broaden. The type and cause of broadening is investigated by proton-dilution and hole-burning experiments. We conclude the broadening to be inhomogeneous.

Code: PQ	Time Slot/Poster Number: 334	Session: Solids: Methods, Poster
Enhanced Resolution Using Dipolar-Encoded HETCOR Spectroscopy at Ultra-High Field: A Critical Advantage for Structural Determination of Peptides in Aligned Bilayers
Riqiang Fu¹; Milton Truong¹; Daniel J. Hibbard³; William Wieczorek⁴; Eric D. Gordon²; Myriam Cotten⁴
¹National High Magnetic Field Laboratory, Tallahassee, FL; ²Dept of Chemical Engineering, Montana State Univ., Bozeman, Montana; ³School of Medicine, University of Washington, Seattle, WA 98104; ⁴Department of Chemistry, Hamilton College, Clinton, NY
Abstract
High resolution dipolar-encoded HETCOR (de-HETCOR) spectroscopy has recently been developed to obtain orientational restraints for structural determination of proteins/peptides aligned in lipid bilayers. In particular, the 1H chemical shift information obtained provide complimentary information about the chemical environment of amide protons, which is valuable to yield insights into the structure and interactions of amphipathic helices with bilayer surfaces and aqueous environments. Here, we use multiply 15N-backbone labeled amidated piscidin samples aligned in hydrated lipid bilayers to demonstrate the spectral resolution enhancement in both chemical shift dimensions of the HETCOR spectra at ultra-high field. With improved spectral resolution at higher magnetic field, the de-HETCOR spectroscopy becomes a powerful tool in the structural studies of multiply or uniformly labeled membrane-bound proteins/peptides.

Code: PQ	Time Slot/Poster Number: 335	Session: Solids: Methods, Poster
Resolution improvement in protein MAS solid state NMR via rotor-synchronized spin-echo pulse sequence.
Veniamin Shevelkov; Bernd Reif
Leibniz-Institut für Molekulare Pharmakologie (FMP, Berlin, Germany
Abstract
Recently we suggested high levels of deuteration of protein. This scheme allows to obtain high resolution spectra of SH3 domain without high power decoupling. The experimental line widths are 10 Hz and 20 Hz in the 15N and 1H dimension. We found that local correlation times and motional amplitudes are similar to solution state and line width should be smaller, which is not a case. Our aim is to identify the origin of this broadening and find an approach to eliminate these factors. It has been shown before that application of a Carr-Parcell pulse train during FID in solids can dramatically narrow the resonances. We followed this approach to improve the resolution in a protein.

Code: PQ	Time Slot/Poster Number: 336	Session: Solids: Methods, Poster
On the practical application of wideline QCPMG NMR on half-integer quadrupolar nuclei at high fields
Ivan Hung¹; Kiran K. Shetty¹; Paul D. Ellis²; William W. Brey¹; Zhehong Gan¹
¹National High Magnetic Field Laboratory, Tallahassee, FL; ²Pacific Northwest National Laboratory, Richland, WA
Abstract
Resistive magnets can provide higher magnetic fields than conventional superconducting magnets and their field-sweep capability enables more convenient coverage of wideline spectra compared to frequency-stepping experiments. The application of QCPMG acquisition under the high magnetic field of a 25 T resistive magnet for acquiring large quadrupolar patterns is presented. NMR patterns which have breadths of hundreds to thousands of kilohertz can be efficiently recorded using a combination of QCPMG and magnetic field stepping with negligible hindrance from the inhomogeneity and field fluctuations of powered magnets. In addition, the practical aspects of applying QCPMG for acquisition of wideline powder patterns are investigated, including the effects of using frequency sweeps, as well as different pulse widths and inter-pulse delays.

Code: PQ	Time Slot/Poster Number: 337	Session: Solids: Methods, Poster
Rapid Acquisition of Multidimensional Solid-State NMR Spectra of Proteins Facilitated by Covalently Bound Paramagnetic Tags
Jonathan Helmus; Philippe Nadaud; Christopher Jaroniec
The Ohio State University, Columbus, OH
Abstract
We demonstrate that covalently-bound paramagnetic tags facilitate the rapid acquisition of solid-state NMR spectra of proteins. Specifically, for proteins containing Cu2+-EDTA side-chains (analogs of model protein GB1) we show that high-resolution and sensitivity 2D spectra can be obtained in several minutes, and 3D spectra can be recorded in as little as ~2-3 hours. Within the context of our ongoing structural studies of paramagnetic proteins, the covalent tags are concurrently being used to obtain quantitative electron-nucleus distance restraints. However, this approach toward the rapid acquisition of multidimensional spectra promises to be generally applicable for enhancing the sensitivity of SSNMR experiments in biomacromolecular systems that do not contain native metal ions and/or pose challenges for rapid acquisition strategies employing external paramagnetic dopants.

Code: PQ	Time Slot/Poster Number: 338	Session: Solids: Methods, Poster
2D PASS-CPMG and Applications to Modified Silicate Glasses
Krishna Dey¹; Derrick Kaseman¹; Samanth Farley²; Philip Grandinetti¹
¹The Ohio State University, Columbus, OH; ²Marshall University, Huntington, WV
Abstract
While Magic Angle Flipping (MAF) has been used to quantify Q(n) species in silicate glasses, it requires a special probe. Here, the 2D phase adjusted spinning sideband (PASS) experiment coupled with CPMG detection is presented as an alternative approach using a conventional MAS probe. It is shown that only CPMG/PASS echoes after the even π pulses satisfy the PASS solution, while the echoes after the odd π pulses do not. This new approach is demonstrated on a series of alkali silicate glasses and used to quantify Q(n) disproportionation; an important equilibrium in the thermodynamics of silicate melts. A comparison of these results with other techniques for Q(n) quantification will be given.

Code: PQ	Time Slot/Poster Number: 339	Session: Solids: Methods, Poster
13C Detected aligned sample solid-state NMR experiments applicable to uniformly 13C labeled proteins
Eugene Lin
, San Diego, CA
Abstract
Triple-resonance experiments are being developed for aligned sample solid-state NMR of proteins in order to extend the approach to all backbone and sidechain sites and to improve sensitivity through 13C rather than 15N detection. This requires the detection of 13C signals while simultaneously decoupling the large network of 13C homonuclear couplingspresent in uniformly 13C labeled proteins.. Variations of the PISEMO (polarization inversion spin exchange-modulated observation) enable 1H-13C heteronuclear spin exchange to evolve homonuclear with homonuclear decoupling on both 1H and 13Cwith 13C detection in the , windows of the multiple pulse experiment. Results from uniformly 15N and 13C labeled single crystals of model peptides and of proteins in virus particles and membranes will be shown.

Code: PQ	Time Slot/Poster Number: 340	Session: Solids: Methods, Poster
NMR probe development for In situ NMR Investigations on Direct Alcohol Fuel Cell in Ordinary Shape
Kee Sung Han; Juhee Lee; Oc Hee Han
Daegu Center, Korea Basic Science Institute, Daegu, South Korea
Abstract
The NMR probe developed for in situ analysis of a direct alcohol fuel cell (DAFC) with minimal modification for NMR experiments is introduced. A surface coil is employed so that a DAFC in an ordinary shape and size can be set up in the probe. Only one end plate of the DAFC needs to be replaced to non-conducting G10 from conducting material to minimize the skin depth problem of radio frequency. This probe was successful to obtain the 2D and 13C NMR spectra of a direct methanol fuel cell in operation. Especially for 13C NMR, this probe was superior to the probe with a toroid cavity detector where large background signal from Si-rubber or Teflon gaskets was difficult to remove.

Code: PQ	Time Slot/Poster Number: 341	Session: Solids: Methods, Poster
Biaxial Nematic Formed in a Bent-Core Liquid Crystal: Can 13C NMR Tell?
Ronald Dong¹; Matthias Lehmann²
¹Univeristy of British Columbia, Vancouver, Canada; ²Chemnitz University of Technology, Chemnitz, Germany
Abstract
Bent-core Liquid Crystals (BLC) forming biaxial nematic (N) phases have attracted much scientific interest [1]. 13C NMR has been used to study the N-N transition in a BLC A131 via temperature dependent chemical shifts [2]. Here, it was impossible to tell if the low temperature nematic phase is biaxial. The spinning sideband patterns found in MAS experiments for single crystals and powder (or uniaxial) samples are different [3]. We aim to use the sideband patterns to tell if a phase is or is not a uniaxial phase. A sample ML90 [4] that forms a biaxial nematic has been studied, making use of its biaxial glass at ambient temperature. It is shown that the glass phase of ML90 is not uniaxial.

Code: PQ	Time Slot/Poster Number: 342	Session: Solids: Methods, Poster
Homonuclear Dipolar Recoupling under ultra-fast MAS: What are the best Options?
Olivier Lafon¹; Julien Trébosc¹; Qiang Wang^{1, 2}; Bingwen Hu¹; Feng Deng²; Philippe Corcos³; Jean-Paul Amoureux¹
¹ENSCL, University of Lille 1, Villeneuve D'ascq Cedex, FRANCE; ²Chinese Academy of Sciences, Wuhan, PR China; ³CortecNet, Voisins le Bretonneux, France
Abstract
We describe broadband dipolar recoupling methods, that accomplish, under ultra-fast MAS, the efficient excitation of homonuclear double-quantum coherences. We employ symmetry-based pulse sequences which are either g-encoded or non-g-encoded. The sensitivity and the robustness to both chemical shift anisotropy and offset are examined. This comprehensive analysis results in the identification of satisfactory conditions for dipolar 1H-1H, 19F-19F, 31P-31P recoupling at high magnetic field and high MAS frequencies.

Code: PQ	Time Slot/Poster Number: 343	Session: Solids: Methods, Poster
Isotropic Resolution For 3/2 Spin Quadrupolar Nuclei By Inverse Detection Of Spin ½
Julien Trébosc; Jean-Paul Amoureux; Olivier Lafon; Bingwen Hu; Qiang Wang
UCCS-CNRS UMR8181-Univ Lille1, Villeneuve D'ascq Cedex, France
Abstract
We present a new dipolar-driven HMQC sequence using a t1-split-STMAS block in the indirect dimension for spin 3/2. We call this sequence D-HMQC-ST. Heteronuclear dipolar recoupling is achieved by either SFAM or symmetry based SR421. On the indirect channel, a fully symmetric version of t1-split STMAS produce isotropic resolution in F1 and allows an efficient reconversion of multi-quantum coherences back into observable coherences. The experimental proofs of this concept are shown on 1H-23Na and 31P-23Na D-HETCOR spectra of Na2HPO4 and NaH2PO4 samples on 4 and 1.3mm MAS probes at MAS speed up to 60 kHz. We also present a theoretical description of the evolution of coherences throughout the HMQC sequence for in depth understanding of the mechanisms involved.

Code: PQ	Time Slot/Poster Number: 344	Session: Solids: Methods, Poster
Removing or Utilizing Chemical Shift Anisotropy Effects in 125Te NMR of Thermolectric Tellurides
Yanyan Hu; E.M. Levin; Klaus Schmidt-Rohr
Iowa State University and Ames Laboratory, Ames, IA
Abstract
We analyze pulse sequences for MAS 125Te NMR that remove chemical-shift anisotropy (CSA) broadening, for maximum resolution, or recouple it, to probe local symmetry. For obtaining sideband-free spectra of high-Z spin-1/2 nuclei, we recently identified Gan's magic-angle turning (MAT) experiment, adapted to fast MAS, as a broad-band pulse sequence. We discuss pulse timings that compensate for off-resonance effects over a 1.8 B1 range; how to minimize the duration of decremented z-periods; shearing without artifacts; and maximizing sensitivity by echo-matched filtering. Effects of defects in cubic tellurides are studied by CSA measurements in terms of fast-MAT sideband intensities or CSA dephasing using a three-pulse sequence. Strong CSA dephasing of SnTe signal shows that this nominally cubic material is significantly distorted locally.

Code: PQ	Time Slot/Poster Number: 345	Session: Solids: Methods, Poster
Constraining Intermolecular Protein Structures by Site-Resolved SSNMR Spectroscopy
Andrew J. Nieuwkoop; Ming Tang; Deborah A. Berthold; Luisel R. Lemkau; Elliot J. Brea; Chad M. Rienstra
University of Illinois at Urbana Champaign, Urbana , IL
Abstract
SSNMR has emerged in recent years as an attractive alternative to solution NMR and x-ray crystallography for solving protein structures in systems such as membrane proteins and protein aggregates. Here we show the TEDOR pulse sequence applied to samples with 15N labels on one molecule and 13C labels on another enables the determination of intermolecular correlations. Calculations combining intermolecular TEDOR restraints with intramoleuclar data result in a NMR structure more precise and accurate then without intermolecular data. In addition, the intermolecular packing of GB1 nanocystals can be determined de novo. These TEDOR distances in combination with other restraints types, such as those from 1H detected experiments, will enable the determination of the structures of protein fibrils and protein-protein interfaces.

Code: PQ	Time Slot/Poster Number: 346	Session: Solids: Methods, Poster
Structures of Phospholamban Monomer and Pentamer by a Hybrid Solution and Solid-State NMR Refinement Protocol
Nathaniel J Traaseth; Raffaello Verardi; Lei Shi; Martin Gustavsson; Gianluigi Veglia
University of Minnesota, Minneapolis, MN
Abstract
The single-pass membrane protein phospholamban (PLN) is believed to exist in two oligomeric forms: a) a monomer that directly binds to and inhibits SERCA and b) a pentamer that acts as a storage form within the membrane. In this work, we describe a new hybrid method to calculate the structures of both monomer and pentamer using a combination of solution and solid-state NMR restraints in detergent micelles and lipid bilayers. Hybrid methods such as the one presented in this work will be necessary to tackle challenging biophysical problems such as membrane protein structure determination.

Code: PQ	Time Slot/Poster Number: 347	Session: Solids: Methods, Poster
Indirect Detection via Spin-1/2 Nuclei in Solid State NMR Spectroscopy : Observing Proximities between Protons and Quadrupolar Nuclei
Olivier Lafon¹; Julien Trébosc¹; Sylvain Cristol¹; Qiang Wang^{1, 2}; Bingwen Hu¹; Filipe Vasconcelos¹; Feng Deng²; Jean-Paul Amoureux¹
¹ENSCL, University of Lille 1, Villeneuve D'ascq Cedex, France; ²Wuhan Institute of Physics and Mathematics, Wuhan, PR Chine
Abstract
We present a comprehensive comparison of through-space heteronuclear correlation techniques for solid state NMR, combining indirect detection and single-channel recoupling method. These techniques, named D-HMQC and D-HSQC, do not suffer from dipolar truncation and can be employed to correlate quadrupolar nuclei with spin-1/2 nuclei. We show that, whatever the magnitude of spin interations, D-HMQC experiment offers larger efficiency and higher robustness than D-HSQC. Furthermore, the spectral resolution in both dimensions of proton detected two-dimensional D-HMQC and D-HSQC spectra can be enhanced by applying recently introduced symmetry-based homonuclear dipolar decoupling schemes. This is demonstrated by 1H-13C and 1H-23Na correlation experiments on L-histidine and NaH2PO4, respectively.

Code: PQ	Time Slot/Poster Number: 348	Session: Solids: Methods, Poster
Proton Detection in Rotating Solids - New Methodologies and Applications
Rasmus J. Linser; Murali Dasari; Matthias Hiller; Hartmut Oschkinat; Bernd Reif
FMP, Leibniz-Institut für molekulare Pharmakologie, Berlin, Germany
Abstract
Proton detection in MAS solid state NMR is shown to yield full backbone and side chain resonances for deuterated proteins. New pulse sequences are applied to micro-crystalline and fibrillar proteins, giving a largely improved set of multidimensional correlations for assignment and structure calculation. In particular, applications to the model protein SH3 of alpha-spectrin, Aß1-40, and OmpG are presented.