Maturation of nitrogenase cofactor-the role of a class E radical SAM methyltransferase NifB.
Maturation of nitrogenase cofactor-the role of a class E radical SAM methyltransferase NifB.
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DOI：
10.1016/j.cbpa.2016.02.016
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发表时间：
2016-04
影响因子：
7.8
通讯作者：
Ribbe MW
中科院分区：
文献类型：
--
作者：
Hu Y;Ribbe MW
固氮酶在其活性辅因子位点催化N2-、CO-和CO2-还原等重要反应。指定的M-集群，这个复杂的金属辅因子组装通过生成一个特征的8 Fe-核心之前，插入钼和高柠檬酸盐，完成的M-集群的化学计量。NifB催化自由基SAM依赖的碳化物插入的关键步骤，该步骤伴随着插入“第9”硫和两个4Fe簇合物重排/偶联到M簇合物的完整8 Fe核心中而发生。NifB蛋白家族作为一类新的自由基SAM甲基转移酶的进一步分类表明了这些蛋白在复杂的金属辅因子组装中的一般功能，并为揭示生物系统催化的前所未有的化学反应提供了新的平台。
Nitrogenase catalyzes the important reactions of N2-, CO- and CO2-reduction at its active cofactor site. Designated the M-cluster, this complex metallocofactor is assembled through the generation of a characteristic 8Fe-core prior to the insertion of Mo and homocitrate that completes the stoichiometry of the M-cluster. NifB catalyzes the critical step of radical SAM-dependent carbide insertion that occurs concomitant with the insertion a “9th” sulfur and the rearrangement/coupling of two 4Fe-clusters into a complete 8Fe-core of the M-cluster. Further categorization of a family of NifB proteins as a new class of radical SAM methyltransferases suggests a general function of these proteins in complex metallocofactor assembly and provides a new platform for unveiling unprecedented chemical reactions catalyzed by biological systems.