Code: TOA	Time Slot/Poster Number: 08:30-08:55	Session: Invited
High Frequency DNP-MAS Experiments in Biological Solids
Robert Griffin
Massachusetts Institute of Technology, Cambridge, MA
Abstract
Dynamic nuclear polarization (DNP) is rapidly evolving as an approach to significantly increase sensitivity in MAS NMR experiments. Advances in the field are due to developments on several fronts including new instrumentation, new polarizing agents tailored for specific experiments, and magnetic resonance methodology. In this presentation we review new developments in each of these areas. Advances in instrumentation include tunable gyrotron sources that circumvent the requirement of a superconducting sweep coil and developments in low temperature probe technology. New polarizing agents include molecules that more effectively exploit the cross effect DNP mechanism or are more efficient at polarizing certain nuclear spin species such as low-g nuclei. New methods for performing DNP involve time domain experiments. In addition, we discuss applications of these techniques to structural studies of amyloid and membrane proteins.

Code: TOA	Time Slot/Poster Number: 08:55-09:10	Session: Solids I Methods
1H and 19F Ultrafast MAS DQ-SQ NMR correlation experiments without recoupling
Michael L Deschamps1; Sylvian Cadars1; Valérie Montouillout1; Anne-Laure Rollet2; Matthieu Allix1; Bradley Chmelka3; Ramzy Shahib3; Allen Burton4; Stacey Zones4; Franck Fayon1; Dominique Massiot1
1CNRS-CEMHTI, Orleans, France; 2Université Pierre et Marie Curie, Paris, France; 3University of California, Santa Barbara, California; 4Chevron Texaco Energy Research and Technology Comp, Richmond, California
Abstract
We show that in protonated or fluorinated samples at ultrafast MAS (66.7kHz), the coherence lifetimes are sufficiently long and the remaining homonuclear residual dipolar couplings are still strong enough to generate double-quantum coherences with excellent efficiency using a standard INADEQUATE sequence that is particularly easy to implement: 90°-τ-180°-τ-90°-t1-90°-τ-180°-τ-Acqu. Hence, no recoupling pulse scheme is performed, only the dipolar interaction that is not fully averaged by MAS mediate the DQ coherence creation. As observed before with DQ recoupling sequences, the maximum intensity is observed for the shortest distances, offering a very convenient method without any sample heating due to radiofrequency pulses for the characterization of 1H-1H or 19F-19F proximities in solid state samples.

Code: TOA	Time Slot/Poster Number: 09:10-09:35	Session: Solids I Methods
Self-assembling natural and artificial light-harvesters
Huub De Groot1; Swapna Ganapathy1; Gert Oostergetel4; Michael Reus2; Aline Gomez Maqueo Chew3; Egbert Boekema4; Ute Baumeister6; Francesco Buda1; Piotr Wawrzyniak1; Valerie Huber5; Sanchita Sengupta5; Frank Wuerthner5; Donald Bryant3; Alfred Holzwarth2
1Leiden Institute of Chemistry, Leiden, Netherlands; 2MPI Bioanorganische Chemie, Muelheim a/d Ruhr, Germany; 3The Pennsylvania State University, University Park, PA; 4University of Groningen, Groningen, The Netherlands; 5University of Wurzburg, Wurzburg, Germany; 6University of Halle, Halle, Germany
Abstract
We have developed methods to study the structures of materials that form very efficient supramolecular light-harvesting antennas in bacteria and artificial derivatives of these systems. Solid state NMR spectroscopic techniques are combined with quantum mechanical calculations and cryo-EM imaging or X-ray diffraction to image the stacking and supramolecular organization of chlorophylls. Solid-state NMR and cryoEM, showed how ligated BChl c and d self-assemble into coaxial cylinders to form tubular-shaped elements. In a next step, we generate biomimetic systems and study their structure by proton NMR experiments, allowing for readings of ring currents. The chlorins self-assemble in anti-parallel stacks in planar layers and X-ray powder diffraction measurements revealed the 3D lattice of the packing.

Code: TOA	Time Slot/Poster Number: 09:35-09:50	Session: Solids I Methods
Obtaining homonuclear correlation spectra at 60 kHz MAS and 900 MHz combined with covariance processing
Markus Weingarth1; Rafael Brüschweiler2; Geoffrey Bodehausen1; Piotr Tekely1
1Ecole Normale Supérieure, Paris, France; 2Department of Chemistry and Biochemistry, Tallahassee, Florida
Abstract
High magnetic fields and spinning frequencies can be of great benefit for solid state NMR. However, most dipolar recoupling methods either fail in this challenging regime or require high rf power. We have developed two efficient homonuclear recoupling methods to circumvent these problems. The first, dubbed basic PARIS, is efficient for medium to fast MAS, while PARIS-xy works best for very fast spinning. Both provide broad-band recoupling with low rf power and immunity to rf-inhomogeneity. Their advantages will be exemplified by applications to β-amyloids (PARIS-xy) and to microcrystalline Crh-protein (basic PARIS). The latter will be embedded in a study of first-time application of covariance processing to micro-crystalline proteins. Covariance processing makes it possible to improve resolution, sensitivity and experimental time.

Code: TOA	Time Slot/Poster Number: 09:50-10:15	Session: Solids I Methods
Magic Angle Spinning Studies of Microtubule-Associated and HIV-1 Capsid Protein Assemblies
Shangjin Sun1; Sivakumar Paramasivam1; Si Yan1; Andrew Butterworth1; Yun Han1, 3; Guangjin Hou1, 3; Christine Lightcap4; Amanda Siglin4; Shubbir Ahmed4; John Williams4; In-Ja Byeon2, 3; Jinwoo Ahn2, 3; Angela Gronenborn2, 3; Tatyana Polenova1, 3
1University of Delaware, Newark, DE; 2University of Pittsburgh, Pittsburgh, PA; 3Pittsburgh Center for HIV Protein Interactions, Pittsburgh, PA; 4Beckman Research Institute of City of Hope, Duarte, CA
Abstract
Recent progress in solid-state NMR hardware and methodology has enabled detailed characterization of complex protein assemblies that play important biological roles but are intractable by other high-resolution structural methods. Despite these developments, atomic-level structural and dynamics studies of these large assemblies still remain a challenge from the sensitivity and resolution standpoint. We will present our recent progress in Magic Angle Spinning structural and dynamics investigations of two classes of protein assemblies, i) microtubule-associated protein domains of dynactin and dynein, and ii) HIV-1 capsid protein.