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Slow and Very Fast MAS Solid State NMR Study of Biopolymers
Author(s) -
Pawlak Tomasz,
Paluch Piotr,
Jeziorna Agata,
Bujacz Grzegorz D.,
Potrzebowski Marek J.
Publication year - 2014
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.201300139
Subject(s) - magic angle spinning , spinning , solid state nuclear magnetic resonance , isotropy , chemical shift , materials science , nmr spectra database , spectral line , chemistry , crystallography , analytical chemistry (journal) , nuclear magnetic resonance spectroscopy , nuclear magnetic resonance , physics , stereochemistry , composite material , optics , chromatography , astronomy
Summary In the first part of article, the “NMR Crystallography” approach as tool to fine refinement of solid state structure of biopolymers is presented, employing the α polymorph of L‐polylactide (PLLA) as model. Slow Magic Angle Spinning (MAS) technique (with spinning rate of sample in range from 1.2 kHz to 8.0 kHz) was used to assign 13 C isotropic chemical shifts and values of 13 C δ ii principal elements of chemical shifts tensors (CST). Theoretical 13 C shielding parameters σ ii were obtained employing GIPAW (Gauge Invariant Projector Augmented Wave) method and compared with experimental 13 C δ ii elements. The computed and experimental 13 C CP/MAS spectra for WAND (Wide Angle Neutron Diffraction) geometry of powdered α PLLA were evaluated. It was revealed that the computed model of α PLLA model better fit to experimental NMR spectra. In the second part of article the applications of the new NMR methodology, so called very fast MAS (VF MAS) with sample spinning over 60 kHz are presented. The power of this approach is shown employing the 13 C and 15 N labeled protein, ubiquitin. We revealed that Cross‐Polarization with Variable Contact (CPVC) time sequence under very‐fast MAS condition performed in two‐dimensional (2D) mode is very efficient method to measure accurately the CH and NH distances, and to analyze the dynamics of proteins with overlapped resonances in aliphatic and aromatic regions.