A gratuitous inducer of cat-86, amicetin, inhibits bacterial peptidyl transferase.

Expression of the chloramphenicol resistance gene cat-86 is regulated by translation attenuation. Among the three ribosomally targeted antibiotics that can induce the gene, only amicetin has an unknown mode of action. Here we demonstrate that the nucleoside antibiotic amicetin is an inhibitor of bacterial peptidyl transferase. Thus, the three inducers of cat-86, chloramphenicol, erythromycin, and amicetin, interact with the peptidyl transferase region of bacterial ribosomes.