The Promiscuous Activity of the Radical SAM Enzyme NosL toward Two Unnatural Substrates  

作　　者：Yue Yin Xinjian Ji Qi Zhang 

机构地区：[1]Department of Chemistry,Fudan University,Shanghai 200433,China

出　　处：《Chinese Journal of Chemistry》2021年第9期2417-2421,共5页中国化学（英文版）

基　　金：supported in part by grants from the National Key Research and Development Program(2018Y F A0900402 and 2016Y F A0501302);from the National Natural Science Foundation of China(21822703 and 21921003).

摘　　要：The radical S-adenosyImethionine(SAM)enzyme NosL catalyzes the conversion of L-tryptophan((-Trp,1)to 3-methyl-2-indolic acid(MIA,2),a key in termediate in the biosynthesis of the peptide an tibiotic no siheptide.Previous study showed that this remarkable recombination reaction starts from the cleavage of the Cα-COO^(-) bond to result in a·CO_(2)^(-) radical migration.In contrast to the radical SAM tyrosine lyases,NosL appears unable to cleave the Cα-Cβ bond,which is intrinsically more favorable to be cleaved than the Cα-COO^(-) bond.In this study,we investigate the NosL activity with tryptamine(11)and tryptophol(12),two L-Trp analogues lacking a carboxylate moiety.We showed that NosL cleaves the C1-C2 bond of these two substrates to produce 3-methylindole(7),suggesting that the enzyme can still catalyze a β-scission when the carboxyl group of Trp is absent.We also showed the enzyme exhibits a promiscuous activity,initiating the reaction by abstracting hydrogen atoms from two different sites to produce two sets of products.

关 键 词：BIOSYNTHESIS ANTIBIOTICS Cleavage reactions LYASE Enzyme catalysis 

分 类 号：O62[理学—有机化学]