FLUCTUATIONS, EXCHANGE PROCESSES, AND WATER DIFFUSION IN AQUEOUS PROTEIN SYSTEMS - A STUDY OF BOVINE SERUM-ALBUMIN BY DIVERSE NMR TECHNIQUES
FLUCTUATIONS, EXCHANGE PROCESSES, AND WATER DIFFUSION IN AQUEOUS PROTEIN SYSTEMS - A STUDY OF BOVINE SERUM-ALBUMIN BY DIVERSE NMR TECHNIQUES
复制标题
DOI：
10.1016/s0006-3495(90)82459-0
复制
发表时间：
1990-11-01
影响因子：
3.4
通讯作者：
SCHNUR, G
中科院分区：
文献类型：
--
作者：
KIMMICH, R;GNEITING, T;SCHNUR, G
实验频率，浓度和温度依赖性的氘弛豫时间T1和T2的D2O溶液的牛血清白蛋白的报告和理论上描述在一个封闭的形式没有正式的参数。该理论概念的关键过程是物质交换、水分子在蛋白质粗糙表面上的平移扩散、大分子在蛋白质粗糙表面上的翻滚以及大分子的翻滚。此外，除了平均不同氘相的弛豫速率外，材料交换还通过对拉莫尔频率的交换调制对横向弛豫作出贡献。自由水含量决定了高分子物料翻滚的速率限制因子。在一定的类比经典的自由体积理论，“自由体积理论”。存在两个特征水质量分数，其指示水化壳的饱和度（cs. 0.3)和蛋白质翻滚的开始（CO 0.6）。水化壳层中水分子平移自由度的存在已被验证通过直接测量的扩散系数，使用NMR场梯度技术。浓度和温度的依赖性显示出表明自由水簇渗透转变的现象。阈值水含量被发现是ccw。0.43.
Experimental frequency, concentration, and temperature dependences of the deuteron relaxation times T1 and T2 of D2O solutions of bovine serum albumin are reported and theoretically described in a closed form without formal parameters. Crucial processes of the theoretical concept are material exchange, translational diffusion of water molecules on the rugged surfaces of proteins, and tumbling of the macromolecules on the rugged surfaces of proteins, and tumbling of the macromolecules. It is also conclude that, apart from averaging of the relaxation rates in the diverse deutreon phases, material exchange contributes to transverse relaxation by exchange modulation of the Larmor frequency. The rate limiting factor of macromolecule tumbling is determined by the free water content. In a certain analogy to the classical free-volume theory, a "free-volume theory" is presented. There are two characteristic water mass fractions indicating the saturation of the hydration shells (cs .apprxeq. 0.3) and the onset of protein tumbling (CO 0.6). The existence of the translational degrees of freedom of water molecules in the hydration shells has been verified by direct measurement of the diffusion coefficient using an NMR field-gradient technique. The concentration and temperature dependence show phenomena indicating a percolation transition of cluster of free water. The threshold water content was found to be ccw .apprxeq. 0.43.