title: A Flavin-Dependent Decarboxylase-Dehydrogenase-Monooxygenase Assembles the Warhead of α,β-Epoxyketone Proteasome Inhibitors.
abstract: The α,β-epoxyketone proteasome inhibitor TMC-86A was discovered as a previously unreported metabolite of Streptomyces chromofuscus ATCC49982, and the gene cluster responsible for its biosynthesis was identified via genome sequencing. Incorporation experiments with [(13)C-methyl]l-methionine implicated an α-dimethyl-β-keto acid intermediate in the biosynthesis of TMC-86A. Incubation of the chemically synthesized α-dimethyl-β-keto acid with a purified recombinant flavin-dependent enzyme that is conserved in all known pathways for epoxyketone biosynthesis resulted in formation of the corresponding α-methyl-α,β-epoxyketone. This transformation appears to proceed via an unprecedented decarboxylation-dehydrogenation-monooxygenation cascade. The biosynthesis of the TMC-86A warhead is completed by cytochrome P450-mediated hydroxylation of the α-methyl-α,β-epoxyketone.
authors.affiliation: Department of Chemistry, University of Warwick , Coventry CV4 7AL, U.K.
authors.forename: Daniel
authors.initials: D
authors.lastname: Zabala
authors.affiliation: Department of Chemistry, University of Warwick , Coventry CV4 7AL, U.K.
authors.forename: Joshua W
authors.initials: JW
authors.lastname: Cartwright
authors.affiliation: Department of Chemistry, University of Warwick , Coventry CV4 7AL, U.K.
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Roberts
authors.affiliation: School of Chemistry and Manchester Institute of Biotechnology, University of Manchester , Manchester M1 7DN, U.K.
authors.forename: Brian J C
authors.initials: BJ
authors.lastname: Law
authors.affiliation: Department of Chemistry, University of Warwick , Coventry CV4 7AL, U.K.
authors.forename: Lijiang
authors.initials: L
authors.lastname: Song
authors.affiliation: Department of Biochemistry, University of Cambridge , Cambridge CB2 1GA, U.K.
authors.forename: Markiyan
authors.initials: M
authors.lastname: Samborskyy
authors.affiliation: Department of Biochemistry, University of Cambridge , Cambridge CB2 1GA, U.K.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Leadlay
authors.affiliation: School of Chemistry and Manchester Institute of Biotechnology, University of Manchester , Manchester M1 7DN, U.K.
authors.forename: Jason
authors.initials: J
authors.lastname: Micklefield
authors.affiliation: Department of Chemistry, University of Warwick , Coventry CV4 7AL, U.K.
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Challis
mesh_terms: D002262:Carboxy-Lyases / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004138:Dinitrocresols; D004151:Dipeptides / Q000494:pharmacology; D005415:Flavins / Q000378:metabolism*; D008715:Methionine / Q000737:chemistry; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors / Q000494:pharmacology*; D013237:Stereoisomerism; D013302:Streptomyces / Q000201:enzymology
chemical_list: D004138:Dinitrocresols; D004151:Dipeptides; D005415:Flavins; D061988:Proteasome Inhibitors; C405050:TMC 86A; C024132:4,6-dinitro-o-cresol; D003577:Cytochrome P-450 Enzyme System; D008715:Methionine; D046988:Proteasome Endopeptidase Complex; D002262:Carboxy-Lyases