Large ribosomal subunit (LSU) (LSU)

The large ribosomal subunit is a massive ribonucleoprotein complex that serves as the primary site of protein synthesis in all living cells (Wikipedia, 2024). In prokaryotes, it is known as the 50S subunit, while in eukaryotes, it is the 60S subunit (UniProt, 2024). Its primary enzymatic function is the peptidyl transferase activity, which catalyzes the formation of peptide bonds between amino acids during the elongation phase of translation (NCBI, 2023). This subunit is a critical therapeutic target for several major classes of antibiotics, including macrolides, lincosamides, and oxazolidinones, which selectively bind to the bacterial 50S subunit to disrupt protein production (StatPearls, 2023). Because of the structural similarities between bacterial ribosomes and human mitochondrial ribosomes, certain drugs targeting this subunit can exhibit off-target toxicity, such as bone marrow suppression or neuropathies (PubMed, 2014). Beyond infectious diseases, the eukaryotic 60S subunit is also being explored as a potential target for novel anti-cancer therapies aimed at inhibiting the high protein synthesis rates of malignant cells (Nature, 2019). Understanding the structural and functional nuances of the large ribosomal subunit is essential for the development of next-generation antimicrobials and for addressing the growing challenge of antibiotic resistance (PubMed, 2021).

Other names

50S ribosomal subunit60S ribosomal subunitPeptidyl transferase center23S rRNA complex28S rRNA complex

Drugs targeting the large ribosomal subunit primarily inhibit protein synthesis by binding to specific sites such as the peptidyl transferase center (PTC) or the nascent peptide exit tunnel (NPET) (StatPearls, 2023). Macrolides and lincosamides typically block the exit tunnel, preventing the elongation of the polypeptide chain, while oxazolidinones interfere with the formation of the 70S initiation complex by binding to the A-site of the 50S subunit (PubMed, 2014).