文章基本信息

标题：Structure and mechanism of an antibiotics-synthesizing 3-hydroxykynurenine C-methyltransferase
本地全文：下载
作者：Sheng-Chia Chen ; Chi-Hung Huang ; Shu-Jung Lai 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
期号：1
DOI：10.1038/srep10100
语种：English
出版社：Springer Nature
摘要：Streptosporangium sibiricum SibL catalyzes the methyl transfer from S-adenosylmethionine (SAM) to 3-hydroxykynurenine (3-HK) to produce S-adenosylhomocysteine (SAH) and 3-hydroxy-4-methyl-kynurenine for sibiromycin biosynthesis. Here, we present the crystal structures of apo-form Ss -SibL, Ss -SibL/SAH binary complex and Ss -SibL/SAH/3-HK ternary complex. Ss -SibL is a homodimer. Each subunit comprises a helical N-terminal domain and a Rossmann-fold C-terminal domain. SAM (or SAH) binding alone results in domain movements, suggesting a two-step catalytic cycle. Analyses of the enzyme-ligand interactions and further mutant studies support a mechanism in which Tyr134 serves as the principal base in the transferase reaction of methyl group from SAM to 3-HK.