通过核磁共振证明蛋白质疏水腔内存在位置无序的水。

Demonstration of positionally disordered water within a protein hydrophobic cavity by NMR.

作者信息

Ernst J A, Clubb R T, Zhou H X, Gronenborn A M, Clore G M

机构信息

Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.

出版信息

Science. 1995 Mar 24;267(5205):1813-7. doi: 10.1126/science.7892604.

DOI:10.1126/science.7892604

PMID:7892604

Abstract

The presence and location of water of hydration (that is, bound water) in the solution structure of human interleukin-1 beta (hIL-1 beta) was investigated with water-selective two-dimensional heteronuclear magnetic resonance spectroscopy. It is shown here that in addition to water at the surface of the protein and ordered internal water molecules involved in bridging hydrogen bonds, positionally disordered water is present within a large, naturally occurring hydrophobic cavity located at the center of the molecule. These water molecules of hydration have residency times in the range of 1 to 2 nanoseconds to 100 to 200 microseconds and can be readily detected by nuclear magnetic resonance (NMR). Thus, large hydrophobic cavities in proteins may not be truly empty, as analysis of crystal structures appears to show, but may contain mobile water molecules that are crystallographically invisible but detectable by NMR.

摘要

利用水选择性二维异核磁共振波谱研究了人白细胞介素-1β（hIL-1β）溶液结构中结合水（即水化水）的存在情况和位置。结果表明，除了蛋白质表面的水以及参与桥连氢键的有序内部水分子外，在位于分子中心的一个大的天然疏水腔内还存在位置无序的水。这些水化水分子的驻留时间在1至2纳秒到100至200微秒范围内，并且可以通过核磁共振（NMR）轻易检测到。因此，蛋白质中的大疏水腔可能并非如晶体结构分析所显示的那样真正为空，而是可能包含在晶体学上不可见但可通过NMR检测到的移动水分子。