Staphylococcus aureus 50S ribosomal subunit (50S subunit)

The Staphylococcus aureus 50S ribosomal subunit is a massive ribonucleoprotein complex that serves as the catalytic heart of the bacterial translation machinery (Wilson, 2014, Nature Reviews Microbiology) [1]. It is composed of the 23S and 5S ribosomal RNAs (rRNA) and approximately 34 ribosomal proteins, which together coordinate the formation of peptide bonds at the peptidyl transferase center (PTC) and the subsequent passage of the nascent protein through the exit tunnel (Belousoff et al., 2017, Molecular Cell) [2]. Because protein synthesis is essential for bacterial viability and the production of virulence factors, this subunit is a premier target for several classes of antibiotics used to treat Staphylococcus aureus infections, including those caused by methicillin-resistant (MRSA) strains (StatPearls, 2023) [3]. Drugs such as macrolides, lincosamides, and oxazolidinones bind to specific pockets within the 23S rRNA, effectively halting translation by either preventing peptide bond formation or physically obstructing the exit tunnel (Eyal et al., 2015, PNAS) [4]. However, the clinical utility of these drugs is frequently challenged by the evolution of resistance mechanisms, such as the enzymatic methylation of the 23S rRNA by Erm or Cfr methyltransferases, which prevents drug binding (Munita & Arias, 2016, Microbiology Spectrum) [5].

Other names

Staphylococcus aureus large ribosomal subunit50S ribosomeLarge ribosomal subunit23S/5S ribosomal complex

Inhibition of bacterial protein synthesis by binding to the 23S rRNA of the 50S ribosomal subunit, which interferes with peptidyl transferase activity or blocks the nascent peptide exit tunnel.