ABSTRACT Sulfur‐containing natural products are widely distributed in nature. Yatakemycin (YTM) is a complex antitumor and antifungal antibiotic featuring a typical cyclopropane moiety as the pharmacophore and containing an S ‐methyl thioester moiety. In this study, functional characterization of three genes ( ytkG/F/W ) within the biosynthetic gene cluster (BGC) revealed their roles in sulfur transfer and subsequent S ‐methylation to form the S ‐methyl thioester moiety. Identification of the sulfur source further suggests that the S ‐methyl thioester formation is an intersection between primary and secondary metabolic pathways. Additionally, we demonstrate that a key O ‐methylation step, catalyzed by a catechol‐ O ‐methyltransferase (MT)‐like MT encoded by a gene outside the BGC, is the prerequisite of the S ‐methyl thioester formation. Notably, the catalytic mechanism of YtkW, an unprecedented thiocarboxylic acid S ‐MT, was elucidated via crystal structure determination, molecular docking, and relevant mutagenesis‐based analyses. Based on these findings, a plausible early‐stage biosynthetic pathway for YTM involving S ‐methyl thioester formation is proposed, which not only advances the biosynthetic understanding of YTM but also provides promising tools for exploring structural diversification of this antibiotic.
Feng et al. (Thu,) studied this question.