1. A Flavin-Dependent Decarboxylase-Dehydrogenase-Monooxygenase Assembles the Warhead of α,β-Epoxyketone Proteasome Inhibitors.
- Author
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Zabala D, Cartwright JW, Roberts DM, Law BJ, Song L, Samborskyy M, Leadlay PF, Micklefield J, and Challis GL
- Subjects
- Carboxy-Lyases metabolism, Cytochrome P-450 Enzyme System metabolism, Dinitrocresols, Dipeptides pharmacology, Methionine chemistry, Proteasome Endopeptidase Complex metabolism, Stereoisomerism, Streptomyces enzymology, Flavins metabolism, Proteasome Inhibitors pharmacology
- 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.
- Published
- 2016
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