School of Chemistry, University of Hyderabad, Hyderabad 50046, India.
School of Chemistry, University of Hyderabad, Hyderabad 50046, India.
Biophys Chem. 2024 Sep;312:107286. doi: 10.1016/j.bpc.2024.107286. Epub 2024 Jun 28.
H-H nuclear cross-relaxation experiments have been carried out with lysozyme in variable glycerol viscosity to study intramolecular motion, self-diffusion, and isotropic rigid-body rotational tumbling at 298 K, pH 3.8. Dynamics of intramolecular H-H cross-relaxation rates, the increase in internuclear spatial distances, and lateral and rotational diffusion coefficients all show fractional viscosity dependence with a power law exponent κ in the 0.17-0.83 range. The diffusion coefficient of glycerol D with the bulk viscosity itself is non-Stokesian, having a fractional viscosity dependence on the medium viscosity (D ∼ η, κ ≈ 0.71). The concurrence and close similarity of the fractional viscosity dependence of glycerol diffusion on the one hand, and diffusion and intramolecular cross-relaxation rates of the protein on the other lead to infer that relaxation of glycerol slaves protein relaxations. Glycerol-transformed native lysozyme to a quasi-native state does not affect the conclusion that both global and internal fluctuations are slaved to glycerol relaxation.
已经在不同甘油粘性的溶菌酶中进行了 H-H 核交叉弛豫实验，以研究 298K、pH3.8 下的分子内运动、自扩散和各向同性刚性体旋转翻滚。分子内 H-H 交叉弛豫率、核间空间距离的增加以及横向和旋转扩散系数的动力学均表现出分数粘性依赖性，幂律指数 κ 在 0.17-0.83 范围内。具有整体粘性的甘油 D 的扩散系数是非斯托克斯的，对介质粘性具有分数粘性依赖性（D∼η，κ≈0.71）。甘油扩散的分数粘性依赖性与一方面的扩散和蛋白质分子内交叉弛豫率的同时出现和密切相似性，导致推断出甘油的松弛使蛋白质松弛。甘油转化的天然溶菌酶变为准天然状态并不影响以下结论，即全局和内部波动都受制于甘油的松弛。
