National Changhua University of Education Institutional Repository : Item 987654321/15144
English  |  正體中文  |  简体中文  |  全文笔数/总笔数 : 6507/11669
造访人次 : 30014617      在线人数 : 438
RC Version 3.2 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
搜寻范围 进阶搜寻

jsp.display-item.identifier=請使用永久網址來引用或連結此文件: http://ir.ncue.edu.tw/ir/handle/987654321/15144

题名: Rapid Ligand Exchange in the MCRred1 form of Methyl-Coenzyme M Reductase
作者: Singh, Kuljeet;Horng, Yih-Chern;Ragsdale, Stephen W.
贡献者: 化學系
日期: 2003-03
上传时间: 2013-01-07T02:15:47Z
出版者: American Chemical Society
摘要: Methyl-coenzyme M reductase (MCR) from Methanothermobacter marburgensis (Mtm), catalyses the final step in methane synthesis in all methanogenic organisms. Methane is produced by coenzyme B-dependent two-electron reduction of methyl-coenzyme M. At the active site of MCR is the corphin cofactor F430, which provides four-coordination through the pyrrole nitrogens to a central Ni ion in all states of the enzyme. The important MCRox1 (“ready”) and MCRred1 (“active”) states contain six-coordinate Ni(I) and differ in their upper axial ligands; furthermore, red1 appears to be two-electrons more reduced than in ox1 and other Ni(II) states that have been studied. On the basis of the reactivity of MCRred1 and MCRox1 with a substrate analogue and inhibitor (3-bromopropanesulfonate) and other small molecules (chloroform, dichloromethane, mercaptoethanol, and nitric oxide), we present evidence that the six-coordinate Ni(I) centers in the MCRred1 and MCRox1 states exhibit markedly different inherent reactivities. MCRred1 reacts faster with chloroform (2100-fold or 35000-fold when corrected for temperature effects), nitric oxide (90-fold), and 3-bromopropanesulfonate (106-fold) than MCRox1. MCRred1 reacts with chloroform and dichloromethane and, like F430, can catalyze dehalogenation reactions and produce lower halogenated products. We conclude that the enhanced reactivity of MCRred1 is due to the replacement of a relatively exchange-inert thiol ligand in MCRox1 with a weakly coordinating upper axial ligand in red1 that can be easily replaced by incoming ligands.
關聯: J. Am. Chem. Soc., 125(9): 2436-2443
显示于类别:[化學系] 期刊論文

文件中的档案:

档案 大小格式浏览次数
index.html0KbHTML630检视/开启


在NCUEIR中所有的数据项都受到原著作权保护.

 

DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - 回馈