]> 2026-07-31T12:14:35+00:00 WBR0507 0 en Prevents attachment of aminoacyl-tRNA to the 30S ribosomal subunit The main mechanism of action of tetracycline antibiotics is the inhibition of protein synthesis by preventing the attachment of aminoacyl-tRNA to the 30S ribosomal subunit. Inhibits the formation of initiation complex Aminoglycosides act mainly on the 30S ribosomal subunit inhibiting the formation of the initiation complex, essential for protein synthesis. Although tetracyclines also bind to the 30S subunit, they do not affect the initiation complex. Inhibits protein synthesis by binding to the 50S ribosomal subunit Clindamycin and macrolides both inhibit protein synthesis by binding to the 50S ribosomal subunit. Tetracyclines do not bind to the 50S subunit. Inhibits the translocation by binding to the 23S rRNA Macrolides act on the 50S ribosomal subunit (particularly the 23S rRNA) to inhibit protein synthesis. They act by preventing the translocation step. Tetracyclines have no action on the 23S rRNA. Inhibits protein elongation by blocking peptidyl-transferase Chloramphenicol inhibits elongation by blocking the peptidyl-transferase halting protein synthesis. Tetracyclines do not affect the peptidyl-transferase enzyme. Embryology Microbiology Pharmacology A 2-year-old girl is brought to the pediatrician because her mother is concerned that her teeth have turned a dark shade of gray since her last check-up. The mother explains that her daughter has been developing normally, but she recently started refusing formula. She also reports that approximately 2 months ago, the child had an episode of cough and sore throat for which she gave her some left-over antibiotics she had at home. Physical exam is unremarkable except for annular gray-brown stains apparent mostly across the front teeth. Which of the following was most likely mechanism of action of the drug used in this patient? A Infectious Disease 2020-10-28T00:47:56Z 2459150.533287 WBR0507