• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Molecular Biology >Structural plasticity and enzyme action: Crystal structures of Mycobacterium tuberculosis peptidyl-tRNA hydrolase
【24h】

Structural plasticity and enzyme action: Crystal structures of Mycobacterium tuberculosis peptidyl-tRNA hydrolase

机译：结构可塑性和酶作用：结核分枝杆菌肽基-tRNA水解酶的晶体结构

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Peptidyl-tRNA hydrolase cleaves the ester bond between tRNA and the attached peptide in peptidyl-tRNA in order to avoid the toxicity resulting from its accumulation and to free the tRNA available for further rounds in protein synthesis. The structure of the enzyme from Mycobacteritan tuberculosis has been determined in three crystal forms. This structure and the structure of the enzyme frorn Escherichia coli in its crystal differ substantially on account of the binding of the C terminus of the E. coli enzyme to the peptide-binding site of a neighboring molecule in the crystal. A detailed examination of this difference led to an elucidation of the plasticity of the binding site of the enzyme. The peptide-binding site of the enzyme is a cleft between the body, of the molecule and a polypepticle Y stretch involving a loop and a helix. This stretch is in the open conformation when the enzyme is in the free state as in the crystals of M. tuberculosis peptidyl-tRNA hydrolase. Furthermore, there is no physical continuity between the tRNA and the peptide-binding sites. The molecule in the E. coli crystal mimics the peptide-bound enzyme molecule. The peptide stretch referred to earlier now closes on the bound peptide. Concurrently, a channel connecting the tRNA and the peptide-binding site opens primarily through the concerted movement of two residues. Thus, the crystal structure of M. tuberculosis peptidyl-tRNA hydrolase when compared with the crystal structure of the E. coli enzyme, leads to a model of structural changes associated with enzyme action on the basis of the plasticity of the molecule. (c) 2007 Elsevier Ltd. All rights reserved.
机译：肽基-tRNA水解酶可裂解肽基-tRNA中的tRNA与连接的肽之间的酯键，以避免其积累而产生的毒性，并释放出可用于后续蛋白质合成的tRNA。来自结核分枝杆菌的酶的结构已经确定为三种晶体形式。由于大肠杆菌酶的C末端与晶体中相邻分子的肽结合位点的结合，这种结构和其晶体中的大肠杆菌酶的结构基本上不同。对这种差异的详细检查导致阐明了酶结合位点的可塑性。该酶的肽结合位点是在该分子的身体与涉及环和螺旋的多消化物Y延伸区之间的缝隙。当酶处于结核分枝杆菌肽基-tRNA水解酶的晶体中处于游离状态时，该伸展处于开放构象。此外，在tRNA和肽结合位点之间没有物理连续性。大肠杆菌晶体中的分子模仿与肽结合的酶分子。现在，前面提到的肽段在结合的肽段上关闭。同时，连接tRNA和肽结合位点的通道主要通过两个残基的协同运动而打开。因此，与大肠杆菌酶的晶体结构相比，结核分枝杆菌肽基-tRNA水解酶的晶体结构导致基于分子可塑性的与酶作用有关的结构变化模型。 （c）2007 Elsevier Ltd.保留所有权利。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号