A Flavin-Dependent Decarboxylase-Dehydrogenase-Monooxygenase Assembles the Warhead of α,β-Epoxyketone Proteasome Inhibitors

Daniel Zabala, Joshua W. Cartwright, Douglas M. Roberts, Brian J.C. Law, Lijiang Song, Markiyan Samborskyy, Peter F Leadlay, Jason Micklefield, Gregory L. Challis

Research output: Contribution to journalArticleResearchpeer-review

16 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)4342-4345
Number of pages4
JournalJournal of the American Chemical Society
Issue number13
Publication statusPublished - 6 Apr 2016
Externally publishedYes

Cite this