Bacterial 70S ribosome peptidyl transferase center (PTC) (PTC)

The bacterial 70S ribosome peptidyl transferase center (PTC) is the catalytic core of the large (50S) ribosomal subunit, responsible for the fundamental chemical reactions of protein synthesis: peptide bond formation and peptide release [3, 7, 9]. As a ribozyme, its activity is primarily mediated by the highly conserved 23S ribosomal RNA (rRNA) rather than ribosomal proteins [7, 11, 13]. The PTC serves as a critical therapeutic target for a diverse array of antibiotics, particularly those used to treat infections caused by Gram-positive pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) [1, 6, 16]. Drugs targeting this site, including oxazolidinones, lincosamides, and pleuromutilins, typically act by sterically hindering the binding or proper orientation of aminoacyl-tRNA and peptidyl-tRNA, thereby halting translation elongation [1, 5, 14, 17]. While highly effective, these agents face challenges such as the emergence of resistance through rRNA mutations or enzymatic modifications (e.g., Cfr methylation) and potential off-target effects on human mitochondrial ribosomes, which share structural similarities with the bacterial target [1, 6, 15, 16].

Other names

Ribosomal peptidyl transferase centerPTCPeptidyl transferase23S rRNA catalytic centerRibosomal catalytic center50S ribosomal subunit peptidyl transferase center

Inhibition of peptide bond formation by sterically hindering the binding or positioning of aminoacyl-tRNA and peptidyl-tRNA within the catalytic site.