Faculty of Mathematics and Computer Science, University of Warmia & Mazury in Olsztyn, Słoneczna 54, 10-710 Olsztyn, Poland.
Faculty of Mathematics and Computer Science, University of Warmia & Mazury in Olsztyn, Słoneczna 54, 10-710 Olsztyn, Poland.
J Magn Reson. 2020 May;314:106721. doi: 10.1016/j.jmr.2020.106721. Epub 2020 Mar 19.
H Nuclear Magnetic Resonance (NMR) relaxometry and Dielectric Spectroscopy (DS) have been exploited to investigate the dynamics of solid proteins. The experiments have been carried out in the frequency range of about 10 kHz-40 MHz for NMR relaxometry and 10Hz-20 MHz for DS. The data sets have been analyzed in terms of theoretical models allowing for a comparison of the correlation times revealed by NMR relaxometry and DS. The H spin-lattice relaxation profiles have been decomposed into relaxation contributions associated with H-H and H-N dipole - dipole interactions. The H-H relaxation contribution has been interpreted in terms of three dynamical processes of time scales of 10s, 10s and 10s. It has turned out that the correlation times do not differ much among proteins and they are only weakly dependent on temperature. The analysis of DS relaxation spectra has also revealed three motional processes characterized by correlation times that considerably depend on temperature in contrast to those obtained from the H relaxation. This finding suggest that for solid proteins there is a contribution to the H spin-lattice relaxation associated with a kind of motion that is not probed in DS as it does not lead to a reorientation of the electric dipole moment.
H 核磁共振（NMR）弛豫和介电谱（DS）已被用于研究固体蛋白质的动力学。实验在 NMR 弛豫的约 10 kHz-40 MHz 和 DS 的 10Hz-20 MHz 的频率范围内进行。根据允许比较 NMR 弛豫和 DS 揭示的相关时间的理论模型对数据集进行了分析。H 自旋晶格弛豫曲线已分解为与 H-H 和 H-N 偶极-偶极相互作用相关的弛豫贡献。H-H 弛豫贡献已根据 10s、10s 和 10s 的时间尺度的三个动力学过程进行了解释。结果表明，蛋白质之间的相关时间差异不大，并且它们仅与温度弱相关。DS 弛豫谱的分析还揭示了三个运动过程，其特征在于相关时间明显依赖于温度，与从 H 弛豫获得的时间不同。这一发现表明，对于固体蛋白质，存在与某种运动相关的 H 自旋晶格弛豫贡献，而这种运动在 DS 中未被探测到，因为它不会导致电偶极矩的重新取向。
