title: Biosynthetic Origin of the Ether Ring in Platensimycin.
abstract: Platensimycin (PTM) and platencin (PTN) are highly functionalized bacterial diterpenoid natural products that target bacterial and mammalian fatty acid synthases. PTM and PTN feature varying diterpene-derived ketolides that are linked to the same 3-amino-2,4-dihydroxybenzoic acid moiety. As a result, PTM is a selective inhibitor for FabF/FabB, while PTN is a dual inhibitor of FabF/FabB and FabH. We previously determined that the PTM cassette, consisting of five genes found in the ptm, but not ptn, gene cluster, partitions the biosynthesis of the PTM and PTN diterpene-derived ketolides. We now report investigation of the PTM cassette through the construction of diterpene production systems in E. coli and genetic manipulation in the PTM-PTN dual overproducer Streptomyces platensis SB12029, revealing two genes, ptmT3 and ptmO5, that are responsible for the biosynthetic divergence between the PTM and PTN diterpene-derived ketolides. PtmT3, a type I diterpene synthase, was determined to be a (16R)-ent-kauran-16-ol synthase, the first of its kind found in bacteria. PtmO5, a cytochrome P450 monooxygenase, is proposed to catalyze the formation of the characteristic 11S,16S-ether ring found in PTM. Inactivation of ptmO5 in SB12029 afforded the ΔptmO5 mutant SB12036 that accumulated nine PTM and PTN congeners, seven of which were new, including seven 11-deoxy-16R-hydroxy-PTM congeners. The two fully processed PTM analogues showed antibacterial activities, albeit lower than that of PTM, indicating that the ether ring, or minimally the stereochemistry of the hydroxyl group at C-16, is crucial for the activity of PTM.
authors.affiliation: Department of Chemistry, ‡Department of Molecular Therapeutics, and §Natural Products Library Initiative at The Scripps Research Institute, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Rudolf
authors.affiliation: Department of Chemistry, ‡Department of Molecular Therapeutics, and §Natural Products Library Initiative at The Scripps Research Institute, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Liao-Bin
authors.initials: LB
authors.lastname: Dong
authors.affiliation: Department of Chemistry, ‡Department of Molecular Therapeutics, and §Natural Products Library Initiative at The Scripps Research Institute, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Karina
authors.initials: K
authors.lastname: Manoogian
authors.affiliation: Department of Chemistry, ‡Department of Molecular Therapeutics, and §Natural Products Library Initiative at The Scripps Research Institute, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Ben
authors.identifier: 0000-0002-9750-5982
authors.initials: B
authors.lastname: Shen
mesh_terms: D000218:Adamantane / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D062365:Aminobenzoates / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D000813:Anilides / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D055162:Biocatalysis; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004224:Diterpenes / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D004986:Ether / Q000378:metabolism*; D016982:Micrococcus luteus / Q000187:drug effects; D009154:Mutation; D013210:Staphylococcus / Q000187:drug effects
chemical_list: D062365:Aminobenzoates; D000813:Anilides; D004224:Diterpenes; D004986:Ether; D003577:Cytochrome P-450 Enzyme System; D000218:Adamantane; C510909:platensimycin