Lipiarmycin, a New Antibiotic from Actinoplanes. III. Mechanism of Action

Abstract

In vivo, at low concentrations (≤1μg/ml), the antibiotic lipiarmycin specifically inhibits RNA synthesis in Bacillus subtilis. At a much higher concentration (100μg/ml), syntheses of other macromolecules such as DNA and protein also appear to be suppressed. In vitro, the antibiotic causes 50% inhibition of DNA-dependent RNA-polymerase from B. subtilis at a concentration of 0.6μg/ml and of that from E. coliat 5~8μg/ml. The activity of Escherichia coli DNA-polymerase I is inhibited 50% at 55~65μg/ml. Lipiarmycin prevents ribonucleoside triphosphate polymerization only if added prior to the association between RNA-polymerase and DNA, and does not affect the elongation rate of RNA chains at concentrations up to 100μg/ml. At that concentration, however, the antibiotic immediately blocks the polymerization of deoxyribonucleotide triphosphates catalyzed by DNA-polymerase I. © 1975, JAPAN ANTIBIOTICS RESEARCH ASSOCIATION. All rights reserved.