Structure and Mechanism of Peptide Methionine Sulfoxide Reductase, an "Anti-Oxidation" Enzyme

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• 作者：W. Todd Lowther ; Nathan Brot ; Herbert Weissbach ; and Brian W. Matthews
• 刊名：Biochemistry
• 出版年：2000
• 出版时间：November 7, 2000
• 年：2000
• 卷：39
• 期：44
• 页码：13307 - 13312
• 全文大小：582K
• 年卷期：v.39,no.44(November 7, 2000)
• ISSN：1520-4995

文摘

Peptide methionine sulfoxide reductase (MsrA) reverses oxidative damage to both freemethionine and methionine within proteins. As such, it helps protect the host organism against stochasticdamage that can contribute to cell death. The structure of bovine MsrA has been determined in two differentmodifications, both of which provide different insights into the biology of the protein. There are threecysteine residues located in the vicinity of the active site. Conformational changes in a glycine-richC-terminal tail appear to allow all three thiols to come together and to participate in catalysis. The structuressupport a unique, thiol-disulfide exchange mechanism that relies upon an essential cysteine as a nucleophileand additional conserved residues that interact with the oxygen atom of the sulfoxide moiety.