Macrolides inhibit translocation by binding reversibly to the subunit 50S of the bacterial ribosome. Tetracyclines compete with tRNA for the A site. Sulphonamides aect folate synthesis. Fluoroquinolones inhibit topoisomerase II, which is a DNA gyrase. Aminoglycosides cause anticodon recognition, which leads to the misreading of the DNA. Beta-lactams interfere with the bacterial cell wall peptidoglycan synthesis. Chloramphenicol inhibits transpeptidation. Puromycin causes premature termination of the peptide chain.