title: Epoxomicin and Eponemycin Biosynthesis Involves gem-Dimethylation and an Acyl-CoA Dehydrogenase-Like Enzyme.
abstract: The α',β'-epoxyketone moiety of proteasome inhibitors confers high binding specificity to the N-terminal threonine in catalytic proteasome β-subunits. We recently identified the epoxomicin and eponemycin biosynthetic gene clusters and have now conducted isotope-enriched precursor feeding studies and comprehensive gene deletion experiments to shed further light on their biosynthetic pathways. Leucine and two methyl groups from S-adenosylmethionine were readily incorporated into the epoxyketone warhead, suggesting decarboxylation of the thioester intermediate. Formation of the α',β'-epoxyketone is likely mediated by conserved acyl-CoA dehydrogenase-like enzymes, as indicated by complete loss of epoxomicin and eponemycin production in the respective knockout mutants. Our results clarify crucial questions in the formation of epoxyketone compounds and lay the foundation for in vitro biochemical studies on the biosynthesis of this pharmaceutically important class of proteasome inhibitors.
authors.affiliation: Pharmaceutical Biology, University of Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany.|German Centre for Infection Research (DZIF), partner site Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany.
authors.forename: Judith
authors.initials: J
authors.lastname: Zettler
authors.affiliation: Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Zubeil
authors.affiliation: Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Microbiology/Biotechnology, University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kulik
authors.affiliation: Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Grond
authors.affiliation: Pharmaceutical Biology, University of Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany. leonard.kaysser@uni-tuebingen.de.|German Centre for Infection Research (DZIF), partner site Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany. leonard.kaysser@uni-tuebingen.de.
authors.forename: Leonard
authors.initials: L
authors.lastname: Kaysser
mesh_terms: D042964:Acyl-CoA Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D000577:Amides / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D007553:Isotope Labeling; D009682:Magnetic Resonance Spectroscopy; D008715:Methionine / Q000378:metabolism; D005810:Multigene Family; D009842:Oligopeptides / Q000096:biosynthesis / Q000737:chemistry; D061988:Proteasome Inhibitors / Q000737:chemistry / Q000378:metabolism; D012694:Serine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000737:chemistry; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D000577:Amides; D009842:Oligopeptides; D061988:Proteasome Inhibitors; C063282:eponemycin; D012694:Serine; D008715:Methionine; D042964:Acyl-CoA Dehydrogenase; C078846:epoxomicin
keywords: acyl-CoA dehydrogenase; biosynthesis; epoxomicin; epoxyketone warhead; proteasome inhibitor