Wlodawer A, Svensson L A, Sjölin L, Gilliland G L
Center for Chemical Physics, National Bureau of Standards, Gaithersburg, Maryland 20899.
Biochemistry. 1988 Apr 19;27(8):2705-17. doi: 10.1021/bi00408a010.
The structure of phosphate-free bovine ribonuclease A has been refined at 1.26-A resolution by a restrained least-squares procedure to a final R factor of 0.15. X-ray diffraction data were collected with an electronic position-sensitive detector. The final model consists of all atoms in the polypeptide chain including hydrogens, 188 water sites with full or partial occupancy, and a single molecule of 2-methyl-2-propanol. Thirteen side chains were modeled with two alternate conformations. Major changes to the active site include the addition of two waters in the phosphate-binding pocket, disordering of Gln-11, and tilting of the imidazole ring of His-119. The structure of the protein and of the associated solvent was extensively compared with three other high-resolution, refined structures of this enzyme.
无磷酸牛核糖核酸酶A的结构已通过约束最小二乘法在1.26埃分辨率下进行了精修，最终R因子为0.15。使用电子位置敏感探测器收集了X射线衍射数据。最终模型包括多肽链中的所有原子（包括氢原子）、188个占据全部或部分位置的水分子位点以及一个2-甲基-2-丙醇分子。13条侧链采用了两种交替构象进行建模。活性位点的主要变化包括在磷酸结合口袋中添加了两个水分子、Gln-11无序化以及His-119的咪唑环倾斜。该蛋白质及其相关溶剂的结构与该酶的其他三个高分辨率精修结构进行了广泛比较。
