Measurements of relative chemical shift tensor orientations in solid-state NMR: new slow magic angle spinning dipolar recoupling experiments

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.

Download Full-text

Accurate determination of chemical shift tensor orientations of single-crystals by solid-state magic angle spinning NMR

Journal of Magnetic Resonance ◽

10.1016/j.jmr.2017.06.012 ◽

2017 ◽

Vol 282 ◽

pp. 89-103 ◽

Cited By ~ 3

Author(s):

Yamini S. Avadhut ◽

Johannes Weber ◽

Jörn Schmedt auf der Günne

Keyword(s):

Solid State ◽

Chemical Shift ◽

Single Crystals ◽

Accurate Determination ◽

Magic Angle Spinning ◽

Chemical Shift Tensor ◽

Magic Angle ◽

Angle Spinning

Download Full-text

Resolution of Sample Heterogeneity in Solid-State NMR Dipolar Recoupling and Magic Angle Spinning Sideband Analyses

Biophysical Journal ◽

10.1016/j.bpj.2010.12.2116 ◽

2011 ◽

Vol 100 (3) ◽

pp. 351a

Author(s):

John D. Gehman ◽

Marc-Antoine Sani ◽

Anil K. Mehta

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Magic Angle Spinning ◽

Magic Angle ◽

Dipolar Recoupling ◽

Angle Spinning ◽

Sample Heterogeneity

Download Full-text

Triosephosphate Isomerase: 15N and 13C Chemical Shift Assignments and Conformational Change upon Ligand Binding by Magic-Angle Spinning Solid-State NMR Spectroscopy

Journal of Molecular Biology ◽

10.1016/j.jmb.2009.10.043 ◽

2010 ◽

Vol 397 (1) ◽

pp. 233-248 ◽

Cited By ~ 14

Author(s):

Yimin Xu ◽

Justin Lorieau ◽

Ann E. McDermott

Keyword(s):

Solid State ◽

Nmr Spectroscopy ◽

Chemical Shift ◽

Solid State Nmr ◽

Triosephosphate Isomerase ◽

Magic Angle Spinning ◽

Magic Angle ◽

Chemical Shift Assignments ◽

13C Chemical Shift ◽

Angle Spinning

Download Full-text

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

10.1101/566729 ◽

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.

Download Full-text