Signal assignments and chemical-shift structural analysis of uniformly13C,15N-labeled peptide, mastoparan-X, by multidimensional solid-state NMR under magic-angle spinning

2004 ◽  
Vol 28 (4) ◽  
pp. 311-325 ◽  
Author(s):  
Toshimichi Fujiwara ◽  
Yasuto Todokoro ◽  
Hajime Yanagishita ◽  
Midori Tawarayama ◽  
Toshiyuki Kohno ◽  
...  
Keyword(s):  
Solid State ◽  
Structural Analysis ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Angle Spinning

A 13C solid-state NMR investigation of four cocrystals of caffeine and theophylline

2017 ◽  
Vol 73 (3) ◽  
pp. 234-243 ◽  
Author(s):  
Nicolas J. Vigilante ◽  
Manish A. Mehta
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Chemical Shifts ◽  
Active Pharmaceutical Ingredient ◽  
Magic Angle Spinning ◽  
Chemical Shift Tensor ◽  
Magic Angle ◽  
Isotropic Chemical Shifts ◽  
Angle Spinning

We report an analysis of the 13C solid-state NMR chemical shift data in a series of four cocrystals involving two active pharmaceutical ingredient (API) mimics (caffeine and theophylline) and two diacid coformers (malonic acid and glutaric acid). Within this controlled set, we make comparisons of the isotropic chemical shifts and the principal values of the chemical shift tensor. The dispersion at 14.1 T (600 MHz 1H) shows crystallographic splittings in some of the resonances in the magic angle spinning spectra. By comparing the isotropic chemical shifts of individual C atoms across the four cocrystals, we are able to identify pronounced effects on the local electronic structure at some sites. We perform a similar analysis of the principal values of the chemical shift tensors for the anisotropic C atoms (most of the ring C atoms for the API mimics and the carbonyl C atoms of the diacid coformers) and link them to differences in the known crystal structures. We discuss the future prospects for extending this type of study to incorporate the full chemical shift tensor, including its orientation in the crystal frame of reference.

scholarly journals TmDOTP : An NMR- based Thermometer for Magic Angle Spinning NMR Experiments

2019 ◽  
Author(s):  
Dongyu Zhang ◽  
Boris Itin ◽  
Ann E. McDermott
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Radio Frequency ◽  
Solid State Nmr ◽  
Lanthanide Complex ◽  
Magic Angle Spinning ◽  
Sample Temperature ◽  
Proton Spectrum ◽  
Magic Angle ◽  
Angle Spinning

AbstractSolid state NMR is a powerful tool to probe membrane protein structure and motions in native lipid structures. Sample heating, caused by magic angle spinning and radio frequency irradiation in solid state NMR, produces uncertainties in sample temperature and thermal broadening caused by temperature distributions, which can also lead to sample deterioration. To measure the sample temperature in real time, and to quantify thermal gradients and their dependence on radio frequency irradiation or spinning frequency, we use the chemical shift thermometer TmDOTP, a lanthanide complex. Compared to other NMR thermometers (e.g., the proton NMR signal of water), the proton spectrum of TmDOTP exhibits higher thermal sensitivity and resolution. In addition, the H6 proton in TmDOTP has a large chemical shift (−175 ppm at 275 K) and is well resolved from the rest of the proton spectrum. We identified two populations of TmDOTP, with differing temperatures and dependency on the radio frequency irradiation power, within proteoliposome samples. We interpret these populations as arising from the supernatant and the pellet, which is sedimented from the sample spinning. Our results indicate that TmDOTP is an excellent internal standard for monitoring temperatures of biophysically relevant samples without distorting their properties.

scholarly journals Rapid structural analysis of minute quantities of organic solids by exhausting 1H polarization in solid-state NMR spectroscopy at fast MAS

2021 ◽  
Author(s):  
Zhiwei Yan ◽  
Rongchun Zhang
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Structural Analysis ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Organic Solids ◽  
Solid State Nmr Spectroscopy ◽  
Experimental Time

Solid-state nuclear magnetic resonance (NMR) is a powerful and indispensable tool for structural and dynamic studies of various challenging systems. Nevertheless, it often suffers from significant limitations due to the inherent low signal sensitivity when low- nuclei are involved. Herein, we report an efficient solid-state NMR approach for rapid and efficient structural analysis of minute amounts of organic solids. By encoding staggered chemical shift evolution in the indirect dimension and staggered acquisition in 1H dimension, a proton-detected homonuclear 1H/1H and heteronuclear 13C/1H chemical shift correlation (HETCOR) spectrum can be obtained simultaneously in a single experiment at fast magic-angle-spinning (MAS) conditions with barely increasing experimental time, compared to conventional proton-detected HETCOR experiment. We establish that abundant 1H polarization can be efficiently manipulated and fully utilized in proton-detected solid-state NMR spectroscopy for extraction of more critical structural information and thus reduction of total experimental time.

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