Linezolid's antibacterial mechanism is unique among protein synthesis inhibitors because it:

• A Binds the 30S ribosomal subunit and causes misreading of the genetic code
• B Blocks peptidyl transferase activity at the 50S subunit, preventing peptide bond formation
• C Inhibits the elongation factor G (EF-G) and causes ribosomal stalling
• D Binds the 23S rRNA of the 50S subunit and prevents formation of the 70S initiation complex ✓

Explanation

Linezolid (an oxazolidinone) acts at the earliest step of bacterial protein synthesis: it binds domain V of the 23S rRNA component of the 50S subunit and blocks assembly of the 30S–50S–mRNA–fMet-tRNA 70S initiation complex. This distinct mechanism explains the lack of cross-resistance with other protein synthesis inhibitors. Unlike chloramphenicol, it does not inhibit peptidyl transferase.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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