50S ribosomal subunit (Helicobacter pylori) (50S subunit)

The 50S ribosomal subunit is the larger component of the 70S ribosome in Helicobacter pylori, playing a critical role in bacterial protein synthesis by facilitating peptidyl transferase activity and providing the exit tunnel for nascent polypeptide chains [NCBI, 2023]. It consists of 23S ribosomal RNA (rRNA), 5S rRNA, and approximately 33 ribosomal proteins [UniProt]. In the context of H. pylori, this subunit is a primary pharmacological target for macrolide antibiotics like clarithromycin, which is a key component of standard eradication therapies for gastric infections [StatPearls, 2023]. These drugs bind to the V domain of the 23S rRNA, effectively blocking the exit tunnel and halting translation [PubMed, 2021]. H. pylori infections are strongly associated with chronic gastritis, peptic ulcer disease, and gastric adenocarcinoma, making the 50S subunit a vital target for therapeutic intervention [WHO, 2020]. However, the emergence of resistance due to specific point mutations in the 23S rRNA gene, such as A2142G and A2143G, poses a significant challenge to successful treatment outcomes [Journal of Clinical Medicine, 2022].

Other names

Large ribosomal subunit50S subunit23S ribosomal RNA complexH. pylori 50S ribosome23S rRNA

Antibiotics targeting the 50S subunit, such as macrolides and lincosamides, bind to the 23S ribosomal RNA (rRNA) at or near the peptidyl transferase center. This binding physically obstructs the ribosomal exit tunnel, preventing the elongation of the nascent peptide chain and causing the premature release of peptidyl-tRNA from the ribosome [PubMed, 2021; StatPearls, 2023].