Radical SAM enzymes in methylation and methylthiolation.
Radical SAM enzymes in methylation and methylthiolation.
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甲基化和甲硫基化中的自由基 SAM 酶。
DOI：
10.1039/c2mt20136d
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Broderick,JoanB
中科院分区：
文献类型：
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作者：
Hutcheson,RachelU;Broderick,JoanB
自由基S-腺苷-L-甲硫氨酸（SAM）酶是一个庞大而多样的超家族，其功能范围从通过单个H原子提取的酶活化到涉及一系列步骤的复杂有机和金属辅因子合成。虽然这些酶具有多种功能，但它们具有共同的结构和机制特征。它们都含有一个位点分化的[4Fe-4S]簇，由CX 3CX 2C或类似的基序连接，其在独特的铁上结合SAM。簇合物的[4Fe-4S]1+态还原性切割SAM，产生5′-脱氧腺苷自由基，其用于启动由这些酶催化的多种反应。自由基SAM酶的理解将提出最近的亮点，特别强调催化甲基化和甲硫基化反应的酶。
RadicalS-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 CX3CX2C or similar motif, which binds SAM at the unique iron. The [4Fe–4S]1+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.