Microbial glycosidation of some anthracycline antibiotics by an antibiotic-negative mutant of aclarubicin producer

FR177391, A New Anti-hyperlipidemic Agent from Serratia

FR177391 produced by Serratia liquefaciens No. 1821 enhances differentiation of mouse 3T3-L1 fibroblasts to adipocytes and reduces the circulating levels of triglyceride in C57BL/KsJ-db/bd mice, an obese non-insulin-dependent diabetes mellitus animal model, although its mechanism of actions remained to be unknown. Its active derivative, 20-hydroxy FR177391, and its inactive derivative, 3-hydroxy FR177391 were produced by microbial conversion of FR177391, and biotin-labeled FR177391 was synthesized from 20-hydroxy FR177391 as an active affinity ligand to identify target molecules of FR177391 by chemical genetic approaches.

Cloning and characterization of a glycosyltransferase gene involved in the biosynthesis of anthracycline antibiotic beta-rhodomycin from Streptomyces violaceus

A glycosyltransferase gene, rhoG, involved in the biosynthesis of the anthracycline antibiotic beta-rhodomycin was isolated as a 4.1-kb DNA fragment containing rhoG and its flanking region from Streptomyces violaceus by degenerate and inverse PCR. Sequencing analysis showed that rhoG was located in a gene cluster involved in the biosynthesis of the constitutive deoxysugar of beta-rhodomycin. The function of rhoG was verified by gene disruption, which was generated by replacing the internal 0.9-kb region of S. violaceus chromosome with a fragment including the SacI-blunted region. The rhoG disruption resulted in complete loss of beta-rhodomycin productivity, along with the accumulation of a non-glycosyl intermediate epsilon-rhodomycinone. In addition, the complementation test demonstrated that rhoG restored beta-rhodomycin production in this gene disruptant. These results indicated that rhoG is the glycosyltransferase gene responsible for the glycosylation of epsilon-rhodomycinone in beta-rhodomycin biosynthesis.