H CSA parameters by ultrafast MAS NMR: Measurement and applications to structure refinement.

Solid State Nucl Magn Reson

UK 850 MHz Solid-state NMR Facility, Department of Physics, Millburn House, University of Warwick, Coventry CV4 7AL, UK. Electronic address:

Published: October 2017


Category Ranking

98%

Total Visits

921

Avg Visit Duration

2 minutes

Citations

20

Article Abstract

A H anisotropic-isotropic chemical shift correlation experiment which employs symmetry-based recoupling sequences to reintroduce the chemical shift anisotropy in ν and ultrafast MAS to resolve H sites in ν is described. This experiment is used to measure H shift parameters for L-ascorbic acid, a compound with a relatively complex hydrogen-bonding network in the solid. The H CSAs of hydrogen-bonded sites with resolved isotropic shifts can be extracted directly from the recoupled lineshapes. In combination with DFT calculations, hydrogen positions in crystal structures obtained from X-ray and neutron diffraction are refined by comparison with simulations of the full two-dimensional NMR spectrum. The improved resolution afforded by the second dimension allows even unresolved hydrogen-bonded sites H to be assigned and their shift parameters to be obtained.

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ssnmr.2017.02.002DOI Listing

Publication Analysis

Top Keywords

ultrafast mas
8
chemical shift
8
shift parameters
8
hydrogen-bonded sites
8
csa parameters
4
parameters ultrafast
4
mas nmr
4
nmr measurement
4
measurement applications
4
applications structure
4

Similar Publications

The thermodynamic equilibrium assumption often invoked in modeling ion migration in solid-state materials remains insufficient to capture the true migration behavior of Li ions, particularly in less-crystalline superionic conductors that exhibit anomalously high Li ion conductivity. Such materials challenge classical frameworks and necessitate a lattice dynamics-based perspective that explicitly accounts for nonequilibrium phonon interactions and transient structural responses. Here, we uncover a phonon-governed Li ion migration mechanism in garnet-structured superionic conductors by comparing Ta-doped LiLaZrTaO (LLZTO4) to its undoped analogue, LiLaZrAlO (LLZO).

View Article and Find Full Text PDF

We present ultrafast magic-angle spinning (MAS) at 160 kHz in solid-state nuclear magnetic resonance (NMR), demonstrating unprecedented spectral quality and coherence lifetimes in proton-detected experiments on biomolecular systems. By optimizing experimental and sample conditions and utilizing advanced filling and handling tools, we achieve superior resolution on both microcrystalline and membrane-reconstituted proteins, paving the way for new applications in structural biology.

View Article and Find Full Text PDF

Phytochromes are red-light-sensitive biliprotein photoreceptors that control a variety of physiological processes in plants, fungi, and bacteria. Lately, greater attention has been paid to these photoreceptors due to their potential as fluorescent probes for deep-tissue microscopy. Such fluorescing phytochromes have been generated by multiple amino acid substitutions in weakly fluorescent wild-type (WT) proteins.

View Article and Find Full Text PDF

The properties of materials containing azobenzene depend strongly on the dynamics of and isomerization which in turn are influenced by the presence of different possible tautomers. Two commonly used food azo dyes, Allura Red (ALR) and Amaranth (AMA), were studied by NMR spectroscopy to experimentally determine their tautomeric forms and then theoretically rationalized. Variable temperature 2D H-N HMBC NMR provided a direct measure of the hydrazone percentage of the dyes in solution which was complimented by H ultrafast magic-angle spinning (MAS) and C CPMAS solid state NMR to characterize the structures of the solid dyes alone and incorporated into chitosan films designed to disassemble upon exposure to light and water.

View Article and Find Full Text PDF

Robust Heteronuclear Correlations for Sub-milligram Protein in Ultrafast Magic-Angle Spinning Solid-State NMR.

J Am Chem Soc

February 2025

National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, C

Proton-detected solid-state nuclear magnetic resonance (ssNMR) under ultrafast magic-angle spinning (MAS) has become a powerful tool for elucidating the structures of proteins with sub-milligram quantities, where establishing C-N correlations is essential. However, traditional C-N cross-polarization (CP), effective at lower MAS frequencies, suffers diminished efficiency under ultrafast MAS conditions. To overcome this limitation, we developed a robust method for selective polarization between insensitive nuclei (SPINE).

View Article and Find Full Text PDF