Consecutive Methylation Catalyzed by TsrM,an Atypical Class B Radical SAM Methylase  

作　　者：Runze Wu Wei Ding Qi Zhang 

机构地区：[1]Department of Chemistry,Fudan University,Shanghai 200433,China [2]State Key Laboratory of Microbial Metabolism,School of Life Sciences&Biotechnology,Shanghai Jiao Tong University,Shanghai,200240,China

出　　处：《Chinese Journal of Chemistry》2022年第14期1693-1698,共6页中国化学（英文版）

基　　金：supported by grants from the National Key Research and Development Program(2018YFA0900402 and 2021YFA0910501);the National Natural Science Foundation of China(21822703,21921003,and 32070050);the funding of Innovative research team of high-level local universities in Shanghai and a key laboratory program of the Education Commission of Shanghai Municipality(ZDSYS14005);West Light Foundation of The Chinese Academy of Sciences xbzg-zdsys-202105.

摘　　要：TsrM is a cobalamin-dependent radical S-adenosylmethionine(SAM)methyltransferase belonging to the Class B radical SAM methylase(RSM)family.This enzyme catalyzes the C-2 methylation of L-tryptophan to produce 2-methyltrytophan(2-MeTrp),an intermediate involved in the biosynthesis of thiostrepton A.In this work,we report characterization of an unexpected activity of TsrM,which carries out an additional methylation reaction on the product 2-MeTrp.A series of isotopic labeling studies and assays with different Trp analogs revealed that TsrM is able to transfer a methyl group from SAM to the C4 of 2-MeTrp to produce 2,4-dimethyltryptophan.These results reveal the intriguing substrate specificity of TsrM,further expanding the reaction promiscuity of the radical SAM superfamily enzymes.

关 键 词：BIOSYNTHESIS BIOTRANSFORMATIONS Catalytic promiscuity Enzyme METHYLTRANSFERASE 

分 类 号：O62[理学—有机化学]