Erythromycin, a macrolide antibiotic, inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit. What specific step in translation does it primarily block?
- A Translocation of the ribosome along mRNA ✓
- B Peptidyl transferase activity
- C Initiation complex formation
- D Aminoacyl-tRNA binding to the A site
Correct answer: A. Translocation of the ribosome along mRNA
Explanation
Macrolides bind to the 50S subunit and block the translocation step, preventing the movement of the ribosome along the mRNA. By blocking translocation, macrolides prevent the elongation of the peptide chain, halting protein synthesis. This bacteriostatic action makes them effective against susceptible respiratory pathogens. Chloramphenicol inhibits peptidyl transferase. Tetracyclines block aminoacyl-tRNA binding. Linezolid inhibits initiation complex formation.
Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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