Which of the following classes of antibiotics is known for inhibiting protein synthesis?

The class of antibiotics known for inhibiting protein synthesis is tetracyclines. These antibiotics achieve their effect by binding to the 30S ribosomal subunit of bacteria, which interferes with the translation process necessary for protein synthesis. This binding prevents the attachment of aminoacyl-tRNA to the ribosomal acceptor site, ultimately halting bacterial growth and reproduction.

In contrast, beta-lactams work by inhibiting cell wall synthesis, disrupting the structure and integrity of the bacterial cell wall, leading to cell lysis. Fluoroquinolones target bacterial DNA gyrase and topoisomerase IV, enzymes crucial for DNA replication and repair, rather than protein synthesis. Glycopeptides, such as vancomycin, also inhibit cell wall synthesis by preventing cross-linking of peptidoglycan layers in the bacterial cell wall. Therefore, the action of tetracyclines on the ribosomal subunit is what makes them specifically known for inhibiting protein synthesis among the listed options.