Identification of two genes from Streptomyces argillaceus encoding glycosyltransferases involved in transfer of a disaccharide during biosynthesis of the antitumor drug mithramycin.

ABSTRACT: Mithramycin is an antitumor polyketide drug produced by Streptomyces argillaceus that contains two deoxysugar chains, a disaccharide consisting of two D-olivoses and a trisaccharide consisting of a D-olivose, a D-oliose, and a D-mycarose. From a cosmid clone (cosAR3) which confers resistance to mithramycin in streptomycetes, a 3-kb PstI-XhoI fragment was sequenced, and two divergent genes (mtmGI and mtmGII) were identified. Comparison of the deduced products of both genes with proteins in databases showed similarities with glycosyltransferases and glucuronosyltransferases from different sources, including several glycosyltransferases involved in sugar transfer during antibiotic biosynthesis. Both genes were independently inactivated by gene replacement, and the mutants generated (M3G1 and

SUBMITTER: Fernandez E 

PROVIDER: S-EPMC107519 | biostudies-literature | 1998 Sep

REPOSITORIES: biostudies-literature