The further crystallographic refinement of trichosanthin at 2.7A resolution and the comparison among the three molecular structures in two crystal forms

作     者：ZHANG, Lei XIA, Zong-Xiang Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, ChinaWU, Shen DONG, Yi-ChengInstitute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China 

作者机构：Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China 

出 版 物：《Chinese Journal of Chemistry》 (中国化学（英文版）)

年 卷 期：1994年第12卷第3期

页      面：223-230页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070303[理学-有机化学] 0703[理学-化学] 

主　　题：Trichosanthin ribosome-inactivating protein C-terminal tail crystallographic refinement structural comparison. 

摘      要：The three-dimensional structure of trichosanthin at 2.7A resolution has been improved further, by refitting one of the C-terminal tails, adjusting 16 residues in the molecular surface regions, discarding some water molecules with high B values, and adjusting weights during the further refinement. The R-factor has been reduced to 18.5% and the r.m.s deviations from ideal geometry are also improved. The structures of the two molecules in the monoclinic asymmetric unit and the only molecule in the orthorhombic asymmetric unit are compared with one another. The main-chain structures for most of the residues in the three molecules are substantially the same. However, the courses of the three C-terminal tails are completely different, and the intermolecular interactions resulting from the particular packing of the molecules in the crystals account for the differences. The strand Be-2 and the preceding B-turn in small domain show large r.m.s. deviations among the three molecules and they are also involved in intermolecular interactions.