Bryant R G
Department of Chemistry, University of Virginia, Charlottesville 22901, USA.
Annu Rev Biophys Biomol Struct. 1996;25:29-53. doi: 10.1146/annurev.bb.25.060196.000333.
The magnetic field and temperature dependence of the water proton nuclear spin-lattice relaxation rate requires that the motion timescale for water molecules in contact with proteins is close to that for pure water at room temperature. Nevertheless, there are a few water molecules, which may be detected by high-resolution, cross-relaxation spectroscopy, that must have relatively long protein-bound lifetimes and that carry the bulk of the relaxation coupling between the protein and the water. The water-protein magnetic coupling affects the interpretation of water relaxation rates in heterogeneous protein systems, such as tissues, and provides new ways to extract useful information about the immobilized components through the effects on the water NMR spectrum. The discussion shows that the conclusions concerning the rapid water molecule motions at the interface are not in conflict with the observations of many water oxygen atom positions in protein crystal structures.
水质子核自旋 - 晶格弛豫率对磁场和温度的依赖性表明，与蛋白质接触的水分子的运动时间尺度接近室温下纯水的运动时间尺度。然而，有一些水分子，可通过高分辨率交叉弛豫光谱检测到，它们必定具有相对较长的与蛋白质结合的寿命，并且承载着蛋白质与水之间大部分的弛豫耦合。水 - 蛋白质磁耦合影响了对诸如组织等异质蛋白质系统中水弛豫率的解释，并通过对水核磁共振谱的影响提供了提取有关固定成分有用信息的新方法。讨论表明，关于界面处水分子快速运动的结论与蛋白质晶体结构中许多水氧原子位置的观测结果并不冲突。
