Structural and Functional Basis of C-Methylation of Coumarin Scaffolds by NovO

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• 作者：Joanna C. Sadler ; Chun-wa H. Chung ; Julie E. Mosley ; Glenn A. BurleyLuke D. Humphreys
• 刊名：ACS Chemical Biology
• 出版年：2017
• 出版时间：February 17, 2017
• 年：2017
• 卷：12
• 期：2
• 页码：374-379
• 全文大小：433K
• ISSN：1554-8937

文摘

C-methylation of aromatic small molecules by C-methyltransferases (C-MTs) is an important biological transformation that involves C–C bond formation using S-adenosyl-l-methionine (SAM) as the methyl donor. Here, two advances in the mechanistic understanding of C-methylation of the 8-position of coumarin substrates catalyzed by the C-MT NovO from Streptomyces spheroides are described. First, a crystal structure of NovO reveals the Arg116-Asn117 and His120-Arg121 motifs are essential for coumarin substrate binding. Second, the active-site His120 is responsible for deprotonation of the phenolic 7-hydroxyl group on the coumarin substrate, activating the rate-determining methyl transfer step from SAM. This work expands our mechanistic knowledge of C-MTs, which could be used in the downstream development of engineered biocatalysts for small molecule C-alkylations.