title: Biosynthesis of dihydrochalcomycin: characterization of a deoxyallosyltransferase (gerGTI).
abstract: Through an inactivation experiment followed by complementation, the gerGTII gene was previously characterized as a chalcosyltransferase gene involved in the biosynthesis of dihydochalcomycin. The glycosyltransferase gerGTI was identified as a deoxyallosyltransferase required for the glycosylation of D-mycinose sugar. This 6-deoxyhexose sugar was converted to mycinose, via bis-O-methylation, following attachment to the polyketide lactone during dihydrochalcomycin biosynthesis. Gene sequence alignment of gerGTI to several glycosyltransferases revealed a consensus sequence motif that appears to be characteristic of the enzymes in this sub-group of the glycosyltransferase family. To characterize its putative function, genetic disruption of gerGTI in the wild-type strain Streptomyces sp. KCTC 0041BP and in the gerGTII-deleted mutant (S. sp. Delta gerGTsss, as well as complementation of gerGTII in S. sp. Delta gerGTss-GTs, were carried out, and the products were analyzed by LC/MS. S. sp. Delta gerGTss-GTs mutant produced dihydrochalconolide macrolide. S. sp. Delta gerGTs and S. sp. Delta gerGTss-GTs complementation of gerGTII yielded dihydrochalconolide without the mycinose sugar. The intermediate shows that gerGTI encodes a deoxyallosyltransferase that acts after gerGTII.
authors.affiliation: Institute of Biomolecule Reconstruction, Department of Pharmaceutical Engineering, Sun Moon University, Asan 336-708, Korea.
authors.forename: Binod Babu
authors.initials: BB
authors.lastname: Pageni
authors.forename: Dinesh
authors.initials: D
authors.lastname: Simkhada
authors.forename: Tae-Jin
authors.initials: TJ
authors.lastname: Oh
authors.forename: Jae Kyung
authors.initials: JK
authors.lastname: Sohng
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002853:Chromatography, Liquid; D020868:Gene Silencing; D005798:Genes, Bacterial / Q000235:genetics; D005816:Genetic Complementation Test; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism*; D016695:Glycosyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018942:Macrolides / Q000737:chemistry / Q000378:metabolism*; D013058:Mass Spectrometry; D053858:Metabolic Networks and Pathways; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000235:genetics; D009154:Mutation / Q000235:genetics; D016415:Sequence Alignment; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: D006027:Glycosides; D018942:Macrolides; C549885:dihydrochalcomycin; C002018:chalcomycin; D016695:Glycosyltransferases