Ribosome antibiotic complexes peptide bond formation

Nucleocidin (LXXX) [353], an adenine nucleoside antibiotic whose structure has recently been elucidated, is also a potent inhibitor of protein synthesis. Studies with this compouna have led to the conclusion that nucleocidin forms a complex with ribosomes which is inactive in peptide bond formation. Binding... 

Ribosome function is complex numerous cofactors are required for initiation, elongation, and termination (for a detailed description please see ref 33). Independent functions can be ascribed to the two subunits. Peptide bond formation takes place on the 50S subunit within the peptidyl transferase center, whereas decoding of the mRNA takes place on the 308 subunit within the decoding A- and P-sites. tRNAs in the P-site and the A-site span both subunits and couple the two events. After each round of peptide bond formation, a translocation step takes place that involves the movement of the mRNA through the ribosome, transfer of the P-site tRNA to the E (or exit)-site, and transfer of the A-site tRNA to the P-site. Most antibiotics target one of the listed steps decoding at either the A-site or the P-site, peptide bond formation within the peptidyl transferase center, or translocation. 

Inhibitors of initiation-complex formation and rRNA-ribosome interactions represent important groups of therapeutic antibiotics, specifically the tetracyclines and aminoglycosides. The third area of protein synthesis that is significantly affected by drugs is peptide bond formation and translocation. Here, chemically diverse antibiotics such as chloramphenicol, lincomycin, and erythromycin are found. 

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