50S ribosomal subunit of Staphylococcus aureus (50S subunit)

The 50S ribosomal subunit of Staphylococcus aureus is the larger component of the bacterial 70S ribosome and is essential for protein biosynthesis (Wilson, 2014, Nature Reviews Microbiology). It contains the peptidyl transferase center (PTC), which catalyzes the formation of peptide bonds between amino acids, and the nascent polypeptide exit tunnel (NPET) through which the growing protein chain passes (Belousoff et al., 2017, Molecular Cell). This subunit is a clinically vital target for several classes of antibiotics, including macrolides, lincosamides, oxazolidinones, and pleuromutilins, which disrupt translation at various stages (Poehlsgaard & Douthwaite, 2005, Nature Reviews Microbiology). Because S. aureus is a major human pathogen responsible for a wide range of infections from skin abscesses to life-threatening sepsis, the 50S subunit is a focal point for drug development (StatPearls, 2023, 'Staphylococcus Aureus'). However, the rapid evolution of resistance mechanisms, such as rRNA methylation by Erm methyltransferases or the Cfr-mediated modification of the PTC, poses a significant challenge to current therapies (Long et al., 2006, Antimicrobial Agents and Chemotherapy). Selective targeting of the bacterial 50S subunit over the human 60S subunit provides the basis for therapeutic efficacy, although some off-target effects on mitochondrial ribosomes can occur due to evolutionary similarities (Garrabou et al., 2007, Antimicrobial Agents and Chemotherapy).

Other names

Large ribosomal subunit of Staphylococcus aureusStaphylococcus aureus 50S ribosomeL-subunit23S/5S ribosomal complex

Inhibition of bacterial protein synthesis by binding to the 23S rRNA or ribosomal proteins within the 50S subunit, which prevents peptide bond formation, blocks the ribosomal exit tunnel, or interferes with the formation of the 70S initiation complex (Wilson, 2014, Nature Reviews Microbiology; StatPearls, 2023, 'Linezolid').