The "rhodanese" fold and catalytic mechanism of 3-mercaptopyruvate sulfurtransferases:: Crystal structure of SseA from Escherichia coli
The "rhodanese" fold and catalytic mechanism of 3-mercaptopyruvate sulfurtransferases:: Crystal structure of SseA from Escherichia coli
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DOI：
10.1016/j.jmb.2003.10.072
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发表时间：
2004-01-09
影响因子：
5.6
通讯作者：
Bordo, D
中科院分区：
文献类型：
--
作者：
Spallarossa, A;Forlani, F;Bordo, D
3-巯基丙酮酸硫转移酶 (MST) 在体外催化硫原子从底物转移到氰化物，产生丙酮酸和硫氰酸盐产物。它们与硫氰酸转移酶家族中观察到的蛋白质折叠表现出明显的结构同源性，由两个结构相关的结构域组成。 MST 在体内的作用及其详细的分子作用机制很少被研究。在这里，我们报道了来自大肠杆菌的MST SseA的晶体结构，这是迄今为止公开的第一个MST三维结构。相对于真核和原核硫氰酸酶，SseA 显示出特定的结构差异。特别是，硫氰酸酶活性位点环的构象变化，承载着家族不变的催化Cys残基，可能支持一种新的硫转移机制，涉及Cys237作为亲核物质和His66、Arg102和Asp262作为辅助催化的残基。 (C) 2003 Elsevier Ltd. 保留所有权利。
3-Mercaptopyruvate sulfurtransferases (MSTs) catalyze, in vitro, the transfer of a sulfur atom from substrate to cyanide, yielding pyruvate and thiocyanate as products. They display clear structural homology with the protein fold observed in the rhodanese sulfurtransferase family, composed of two structurally related domains. The role of MSTs in vivo, as well as their detailed molecular mechanisms of action have been little investigated. Here, we report the crystal structure of SseA, a MST from Escherichia coli, which is the first MST three-dimensional structure disclosed to date. SseA displays specific structural differences relative to eukaryotic and prokaryotic rhodaneses. In particular, conformational variation of the rhodanese active site loop, hosting the family invariant catalytic Cys residue, may support a new sulfur transfer mechanism involving Cys237 as the nucleophilic species and His66, Arg102 and Asp262 as residues assisting catalysis. (C) 2003 Elsevier Ltd. All rights reserved.