title: Characterization of yatakemycin gene cluster revealing a radical S-adenosylmethionine dependent methyltransferase and highlighting spirocyclopropane biosynthesis.
abstract: Yatakemycin (YTM), an antitumor natural product, represents the most potent member of a class of potent anticancer natural products including CC-1065 and duocarmycins. Herein we describe the biosynthetic gene cluster of YTM, which was identified by genome scanning of Streptomyces sp. TP-A0356. This cluster consists of 31 open reading frames (ORFs) and was localized to a 36 kb DNA segment. Moreover, its involvement in YTM biosynthesis was confirmed by cluster deletion, gene replacement, and complementation. Inactivation of ytkT, which encodes a radical S-adenosylmethionine (SAM) protein, created a mutant strain that failed to produce YTM but accumulated a new metabolite, which was structurally elucidated as a precursor that was related to the formation of the cyclopropane ring. More importantly, biochemical characterization of the radical SAM-dependent enzyme YtkT revealed that it is a novel C-methyltransferase and contributes to an advanced intermediate during formation of the cyclopropane ring through a radical mechanism in the YTM biosynthetic pathway. On the basis of in silico analysis, genetic experiments, structure elucidation of the novel intermediate, and biochemical characterization, a biosynthetic pathway for yatakemycin was proposed, which sets the stage to further investigate the novel enzymatic mechanisms and engineer the biosynthetic machinery for the production of novel analogues.
authors.affiliation: State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.forename: Xin-Ya
authors.initials: XY
authors.lastname: Chen
authors.forename: Qing-Li
authors.initials: QL
authors.lastname: He
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Gong-Li
authors.initials: GL
authors.lastname: Tang
mesh_terms: D000970:Antineoplastic Agents / Q000378:metabolism*; D001688:Biological Products / Q000378:metabolism; D003521:Cyclopropanes / Q000737:chemistry*; D000080890:Duocarmycins; D007211:Indoles / Q000378:metabolism*; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family; D011758:Pyrroles / Q000378:metabolism*; D015203:Reproducibility of Results; D012436:S-Adenosylmethionine / Q000378:metabolism*; D013141:Spiro Compounds / Q000737:chemistry / Q000378:metabolism*; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D001688:Biological Products; D003521:Cyclopropanes; D000080890:Duocarmycins; D007211:Indoles; D011758:Pyrroles; D013141:Spiro Compounds; C474180:yatakemycin; D012436:S-Adenosylmethionine; C030797:cyclopropane; D008780:Methyltransferases