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#erythromycin

2 public questions tagged with this topic.

Microbial Physiology

The mechanism of action of macrolides (e.g., erythromycin) is:

Macrolides such as erythromycin, azithromycin and clarithromycin belong to group characterized by large 14-, 15- or 16-membered lactone rings decorated with deoxy sugar moieties L-cladinose and desosamine that confer binding specificity. They lodge within the nascent peptide exit tunnel of the large ribosomal subunit. Bacterial ribosomes comprise small 30S and large 50S subunits; 50S contains 23S rRNA that forms the peptidyl transferase center and tunnel spanning subunit. Macrolides bind at nucleotides 2058 and 2059 of domain V of 23S rRNA near the peptidyl transferase center, partially occlud

Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 7: Macrolides Binding to 50S Ribosomal Subunit.

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Eukaryotes gene regulation

Erythromycin blocks which step?

Erythromycin macrolide contains 14-membered lactone ring with L-desosamine sugar binding nascent peptide exit tunnel of 50S subunit near peptidyl transferase center contacting 23S rRNA A2058, A2059. Binding does not prevent peptide bond formation initially but blocks nascent chain progression through tunnel after six to eight residues, inhibiting translocation where deacylated tRNA moves P to E and peptidyl-tRNA A to P via EF-G. Abortive peptidyl-tRNA drop-off occurs terminating translation prematurely. Resistance via erm methyltransferase methylating A2058 preventing interaction. Bacteriostat

Ref: Lodish et al., Molecular Cell Biology, 9th ed., Chapter 5: Erythromycin Block of Elongation-Translocation

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