Chalcomycin biosynthesis gene cluster from Streptomyces bikiniensis: novel features of an unusual ketolide produced through expression of the chm polyketide synthase in Streptomyces fradiae.

ABSTRACT: Chalcomycin, a 16-membered macrolide antibiotic made by the bacterium Streptomyces bikiniensis, contains a 2,3-trans double bond and the neutral sugar D-chalcose in place of the amino sugar mycaminose found in most other 16-membered macrolides. Degenerate polyketide synthase (PKS)-specific primers were used to amplify DNA fragments from S. bikiniensis with very high identity to a unique ketosynthase domain of the tylosin PKS. The resulting amplimers were used to identify two overlapping cosmids encompassing the chm PKS. Sequencing revealed a contiguous segment of >60 kb carrying 25 putative genes for biosynthesis of the polyketide backbone, the two deoxysugars, and enzymes involved in modification of precursors of chalcomycin or resistance to it. The chm PKS lacks the ketoreductase and deh

SUBMITTER: Ward SL 

PROVIDER: S-EPMC529187 | biostudies-literature | 2004 Dec

REPOSITORIES: biostudies-literature