4qvg

Publication Abstract from PubMed

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.

Structure and mechanism of an antibiotics-synthesizing 3-hydroxykynurenine C-methyltransferase.,Chen SC, Huang CH, Lai SJ, Liu JS, Fu PK, Tseng ST, Yang CS, Lai MC, Ko TP, Chen Y Sci Rep. 2015 May 11;5:10100. doi: 10.1038/srep10100. PMID:25960001^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.