title: Solanapyrone synthase, a possible Diels-Alderase and iterative type I polyketide synthase encoded in a biosynthetic gene cluster from Alternaria solani.
abstract: The solanapyrone biosynthetic gene cluster was cloned from Alternaria solani. It consists of six genes-sol1-6-coding for a polyketide synthase, an O-methyltransferase, a dehydrogenase, a transcription factor, a flavin-dependent oxidase, and cytochrome P450. The prosolanapyrone synthase (PSS) encoded by sol1 was expressed in Aspergillus oryzae and its product was identified as desmethylprosolanapyrone I (8). Although PSS is closely related to the PKSs/Diels-Alderases LovB and MlcA of lovastatin and compactin biosynthesis, it did not catalyze cycloaddition. Sol5, encoding a flavin-dependent oxidase (solanapyrone synthase, SPS), was expressed in Pichia pastoris and purified. The purified recombinant SPS showed activity for the formation of (-)-solanapyrone A (1) from achiral prosolanapyrone II (2), establishing that this single enzyme catalyzes both the oxidation and the subsequent cycloaddition reaction, possibly as a Diels-Alder enzyme.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Kasahara
authors.forename: Takanori
authors.initials: T
authors.lastname: Miyamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujimoto
authors.forename: Hiroki
authors.initials: H
authors.lastname: Oguri
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Tokiwano
authors.forename: Hideaki
authors.initials: H
authors.lastname: Oikawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ebizuka
authors.forename: Isao
authors.initials: I
authors.lastname: Fujii
mesh_terms: D000528:Alternaria / Q000201:enzymology*; D055162:Biocatalysis; D002942:Circular Dichroism; D003500:Cyclization; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family; D009281:Naphthalenes / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D048630:Polyketide Synthases / Q000235:genetics / Q000378:metabolism*; D011753:Pyrones / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D005656:Fungal Proteins; D009281:Naphthalenes; D011753:Pyrones; D011994:Recombinant Proteins; D048630:Polyketide Synthases; C113266:solanapyrone A; D019746:Intramolecular Oxidoreductases; C113265:solanapyrone synthase