title: Deciphering indolocarbazole and enediyne aminodideoxypentose biosynthesis through comparative genomics: insights from the AT2433 biosynthetic locus.
abstract: AT2433, an indolocarbazole antitumor antibiotic, is structurally distinguished by its aminodideoxypentose-containing disaccharide and asymmetrically halogenated N-methylated aglycon. Cloning and sequence analysis of AT2433 gene cluster and comparison of this locus with that encoding for rebeccamycin and the gene cluster encoding calicheamicin present an opportunity to study the aminodideoxypentose biosynthesis via comparative genomics. The locus was confirmed via in vitro biochemical characterization of two methyltransferases--one common to AT2433 and rebeccamycin, the other unique to AT2433--as well as via heterologous expression and in vivo bioconversion experiments using the AT2433 N-glycosyltransferase. Preliminary studies of substrate tolerance for these three enzymes reveal the potential to expand upon the enzymatic diversification of indolocarbazoles. Moreover, this work sets the stage for future studies regarding the origins of the indolocarbazole maleimide nitrogen and indolocarbazole asymmetry.
authors.affiliation: Laboratory for Biosynthetic Chemistry, Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin, Madison, 53705, USA.
authors.forename: Qunjie
authors.initials: Q
authors.lastname: Gao
authors.forename: Changsheng
authors.initials: C
authors.lastname: Zhang
authors.forename: Sophie
authors.initials: S
authors.lastname: Blanchard
authors.forename: Jon S
authors.initials: JS
authors.lastname: Thorson
mesh_terms: D000606:Amino Sugars / Q000096:biosynthesis* / Q000737:chemistry; D001483:Base Sequence; D002227:Carbazoles / Q000737:chemistry / Q000378:metabolism*; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D017931:DNA Primers; D053281:Enediynes / Q000737:chemistry*; D023281:Genomics; D008969:Molecular Sequence Data; D005810:Multigene Family; D010429:Pentoses / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: D000606:Amino Sugars; D002227:Carbazoles; D017931:DNA Primers; D053281:Enediynes; D010429:Pentoses