Department of Chemistry and Biochemistry and the Astrobiology Biogeocatalysis Research Center, Montana State University, Bozeman, MT 59717, USA.
Metallomics. 2012 Nov;4(11):1149-54. doi: 10.1039/c2mt20136d. Epub 2012 Sep 19.
Radical S-adenosyl-l-methionine (SAM) enzymes are a large and diverse superfamily with functions ranging from enzyme activation through a single H atom abstraction to complex organic and metal cofactor synthesis involving a series of steps. Though these enzymes carry out a variety of functions, they share common structural and mechanistic characteristics. All of them contain a site-differentiated [4Fe-4S] cluster, ligated by a CX(3)CX(2)C or similar motif, which binds SAM at the unique iron. The 4Fe-4S state of the cluster reductively cleaves SAM to produce a 5'-deoxyadenosyl radical, which serves to initiate the diverse reactions catalyzed by these enzymes. Recent highlights in the understanding of radical SAM enzymes will be presented, with a particular emphasis on enzymes catalyzing methylation and methythiolation reactions.
激进的 S-腺苷甲硫氨酸（SAM）酶是一个庞大而多样化的超家族，其功能从通过单个 H 原子提取到酶激活，再到涉及一系列步骤的复杂有机和金属辅因子合成不等。尽管这些酶具有多种功能，但它们具有共同的结构和机制特征。它们都包含一个位点区分的 [4Fe-4S] 簇，由 CX(3)CX(2)C 或类似的基序连接，该簇将 SAM 结合到独特的铁上。该簇的 4Fe-4S 状态还原切割 SAM 以产生 5'-脱氧腺苷自由基，该自由基用于启动这些酶催化的各种反应。本文将介绍对激进的 SAM 酶的理解的最新重点，特别强调催化甲基化和甲硫基化反应的酶。
