TY - DATA T1 - Biosynthesis of Structurally Unique Fungal Metabolite GKK1032A2:  Indication of Novel Carbocyclic Formation Mechanism in Polyketide Biosynthesis PY - 2003/03/28 AU - Hideaki Oikawa UR - https://acs.figshare.com/articles/journal_contribution/Biosynthesis_of_Structurally_Unique_Fungal_Metabolite_GKK1032A_sub_2_sub_Indication_of_Novel_Carbocyclic_Formation_Mechanism_in_Polyketide_Biosynthesis/3697590 DO - 10.1021/jo0267596.s001 L4 - https://ndownloader.figshare.com/files/5788032 KW - polyketide chain KW - nonribosomal peptide synthetase KW - Novel Carbocyclic Formation Mechanism KW - oxidation level KW - GKK 1032. KW - antitumor agent GKK 1032A 2 KW - biosynthesi KW - macroether KW - nonaketide chain KW - novel cyclization mechanisms KW - starter unit KW - 13 C KW - tyrosine hydroxy group KW - Penicillium sp KW - methyl groups KW - polyketide synthase KW - Polyketide Biosynthesis KW - 2 H KW - tricarbocyclic system KW - formation N2 - The biosynthesis of the antitumor agent GKK1032A2 (1) has been investigated by administration of isotopically labeled (13C and 2H) precursors to Penicillium sp. GKK1032. These studies showed that the backbone of 1 is constructed from l-tyrosine and a nonaketide chain flanked with five methyl groups probably by a polyketide synthase and a nonribosomal peptide synthetase hybrid. On the basis of the oxidation level of the starter unit and unusual 13-membered macroether formation between the tyrosine hydroxy group and the polyketide chain, novel cyclization mechanisms on the formation of a tricarbocyclic system and a macroether have been proposed. Involvement of a similar type of cyclization in the biosynthesis of structurally related metabolites is discussed. ER -