 It does so by preventing the formation of the initiation complex , composed of the 30S and 50S subunits of the ribosome , tRNA , and mRNA . Linezolid binds to the 23S portion of the 50S subunit ( the center of peptidyl transferase activity ) , close to the binding sites of chloramphenicol , lincomycin , and other antibiotics . Due to this unique mechanism of action , cross @-@ resistance between linezolid and other protein synthesis inhibitors is highly infrequent or nonexistent . 
