1. A Flavin-Dependent Decarboxylase-Dehydrogenase- Monooxygenase Assembles the Warhead of α,β-Epoxyketone Proteasome Inhibitors.
- Author
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Zabala, Daniel, Cartwright, Joshua W., Roberts, Douglas M., Law, Brian J. C., Lijiang Song, Samborskyy, Markiyan, Leadlay, Peter F., Micklefield, Jason, and Challis, Gregory L.
- Subjects
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FLAVINS , *DEHYDROGENASES , *MONOOXYGENASES , *STREPTOMYCES , *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 [13C-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. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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