title: In vitro reconstitution and crystal structure of p-aminobenzoate N-oxygenase (AurF) involved in aureothin biosynthesis.
abstract: p-Aminobenzoate N-oxygenase (AurF) from Streptomyces thioluteus catalyzes the formation of unusual polyketide synthase starter unit p-nitrobenzoic acid (pNBA) from p-aminobenzoic acid (pABA) in the biosynthesis of antibiotic aureothin. AurF is a metalloenzyme, but its native enzymatic activity has not been demonstrated in vitro, and its catalytic mechanism is unclear. In addition, the nature of the cofactor remains a controversy. Here, we report the in vitro reconstitution of the AurF enzyme activity, the crystal structure of AurF in the oxidized state, and the cocrystal structure of AurF with its product pNBA. Our combined biochemical and structural analysis unequivocally indicates that AurF is a non-heme di-iron monooxygenase that catalyzes sequential oxidation of aminoarenes to nitroarenes via hydroxylamine and nitroso intermediates.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA.
authors.forename: Yoo Seong
authors.initials: YS
authors.lastname: Choi
authors.forename: Houjin
authors.initials: H
authors.lastname: Zhang
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Brunzelle
authors.forename: Satish K
authors.initials: SK
authors.lastname: Nair
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhao
mesh_terms: D010129:4-Aminobenzoic Acid / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification; D002384:Catalysis / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D002867:Chromones / Q000378:metabolism*; D018360:Crystallography, X-Ray; D003470:Culture Media; D004578:Electron Spin Resonance Spectroscopy; D007501:Iron / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D009603:Nitroso Compounds / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D017433:Protein Structure, Secondary; D019163:Reducing Agents / Q000494:pharmacology; D055672:Static Electricity; D013302:Streptomyces / Q000187:drug effects / Q000201:enzymology*; D040681:Structural Homology, Protein; D013379:Substrate Specificity / Q000187:drug effects
chemical_list: D001426:Bacterial Proteins; D002867:Chromones; D003470:Culture Media; D009603:Nitroso Compounds; D019163:Reducing Agents; D008345:Manganese; D007501:Iron; C012198:aureothin; D010129:4-Aminobenzoic Acid