GSE61619
The general mode of translation inhibition by macrolide antibiotics
Macrolides are clinically important antibiotics thought to inhibit bacterial growth by impeding the passage of newly synthesized polypeptides through the nascent peptide exit tunnel of the bacterial ribosome. Recent data challenged this view by showing that macrolide antibiotics can differentially affect synthesis of individual proteins. In order to understand the general mechanism of macrolide action, we used genome-wide ribosome profiling and analyzed the redistribution of ribosomes translating highly expressed genes in bacterial cells treated with high concentrations of macrolide antibiotics. The metagene analysis indicated that inhibition of early rounds of translation, which would be characteristic of the conventional view of macrolide action, occurs only at a limited number of genes. Translation of most genes proceeds past the 5'' proximal codons and can be arrested at more distal codons when the ribosome encounters specific short sequence motifs. The sequence motifs enriched in the sites of arrest are confined to the nascent peptide residues in the peptidyl transferase center but not to the peptide segments that contact the antibiotic molecule in the exit tunnel. This led to the conclusion that the general mode of macrolide action involves selective inhibition of peptide bond formation between specific combinations of donor and acceptor substrates. Additional factors operating in the living cell but not during in vitro protein synthesis may modulate site-specific action of macrolide antibiotics. Overall design: Comparing ribosome distribution in bacterial cells treated with macrolide antibiotics against the control cells.