title: Naphthoquinone-like polyketide isolated from Streptomyces sp. RI-77 and its predicted biosynthetic pathway.
abstract: A novel naphthoquinone-like polyketide, JBIR-85 (1), with a unique skeleton and antioxidative activity was isolated from a culture of Streptomyces sp. RI-77. The planar structure of 1 was established on the basis of extensive NMR and MS analyses. The structure of 1 including the absolute configuration was established via X-ray crystallographic analysis. Since 1 exhibits a unique skeleton, we performed feeding experiments to reconfirm the structure and predict the biosynthetic pathway.
authors.affiliation: Biomedicinal Information Research Center (BIRC),  Japan Biological Informatics Consortium  (JBIC), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Izumikawa
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Satou
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Motohashi
authors.forename: Aya
authors.initials: A
authors.lastname: Nagai
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohnishi
authors.forename: Motoki
authors.initials: M
authors.lastname: Takagi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shin-ya
mesh_terms: D001713:Biphenyl Compounds / Q000494:pharmacology; D018360:Crystallography, X-Ray; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D008968:Molecular Conformation; D015394:Molecular Structure; D009285:Naphthoquinones / Q000737:chemistry / Q000302:isolation & purification*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010851:Picrates / Q000494:pharmacology; D061065:Polyketides / Q000737:chemistry / Q000302:isolation & purification*; D013302:Streptomyces / Q000737:chemistry*
chemical_list: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; C570344:JBIR-85; D009285:Naphthoquinones; D010851:Picrates; D061065:Polyketides; C004931:1,1-diphenyl-2-picrylhydrazyl