Bromomonamycins, unnatural analogues of the monamycin cyclodepsipeptide antibiotics: production, isolation, and biological activity.

Growth of Streptomyces jamaicensis in a low-chloride medium supplemented with NaBr resulted in the biosynthesis of brominated analogues of the natural chlorinated monamycins. Purification of these new compounds was undertaken by Craig countercurrent distribution studies. Diffusion and dilution assays indicated that antibiotic activity of a monamycin was inversely proportional to its unsolvated molecular weight.