title: Tandem enzymatic oxygenations in biosynthesis of epoxyquinone pharmacophore of manumycin-type metabolites.
abstract: Many natural products contain epoxyquinone pharmacophore with unknown biosynthetic mechanisms. Recent genetic analysis of the asukamycin biosynthetic gene cluster proposed enzyme candidates related to epoxyquinone formation for manumycin-type metabolites. Our biochemical studies reveal that 3-amino-4-hydroxyl benzoic acid (3,4-AHBA) precursor is activated and loaded on aryl carrier protein (AsuC12) by ATP-dependent adenylase (AsuA2). AsuE1 and AsuE3, both single-component flavin-dependent monooxygenases, catalyze the exquisite regio- and enantiospecific postpolyketide synthase (PKS) assembly oxygenations. AsuE1 installs a hydroxyl group on the 3,4-AHB ring to form a 4-hydroxyquinone moiety, which is epoxidized by AsuE3 to yield the epoxyquinone functionality. Despite being a single-component monooxygenase, AsuE1 activity is elicited by AsuE2, a pathway-specific flavin reductase. We further demonstrate that the epoxyquinone moiety is critical for anti-MRSA activity by analyzing the bioactivity of various manumycin-type metabolites produced through mutasynthesis.
authors.affiliation: Department of Chemical and Biomolecular Engineering and Energy Biosciences Institute, University of California, Berkeley, CA 94720, USA.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Rui
authors.forename: Moriah
authors.initials: M
authors.lastname: Sandy
authors.forename: Brian
authors.initials: B
authors.lastname: Jung
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhang
mesh_terms: D019817:Benzoic Acid / Q000737:chemistry / Q000378:metabolism; D016227:Benzoquinones / Q000737:chemistry / Q000378:metabolism*; D004138:Dinitrocresols / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D005810:Multigene Family; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D011090:Polyenes / Q000737:chemistry / Q000378:metabolism*; D053284:Polyunsaturated Alkamides / Q000737:chemistry / Q000378:metabolism*; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D016227:Benzoquinones; D004138:Dinitrocresols; D011090:Polyenes; D053284:Polyunsaturated Alkamides; C024132:4,6-dinitro-o-cresol; C004532:quinone; C013404:asukamycin; D019817:Benzoic Acid; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; C023111:epoxidase; C054474:manumycin; D010100:Oxygen