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

The bacterial 50S ribosomal subunit is the larger component of the prokaryotic 70S ribosome in Helicobacter pylori, serving as a fundamental site for protein synthesis [6, 18]. It is composed of 23S and 5S ribosomal RNA (rRNA) and approximately 31 ribosomal proteins, which together catalyze peptide bond formation and facilitate the elongation of nascent polypeptide chains [6, 18]. In the clinical management of H. pylori infections, the 50S subunit is a primary therapeutic target for several antibiotic classes, most notably macrolides like clarithromycin [1, 2]. These drugs typically bind to the peptidyl transferase center or the nascent peptide exit tunnel of the 23S rRNA, effectively halting translation and bacterial growth [4, 8]. The role of the 50S subunit is critical in the pathogenesis of H. pylori, as the bacterium's ability to synthesize proteins is essential for its survival in the acidic gastric environment and for the production of virulence factors [3, 11]. Chronic infection with H. pylori is a leading cause of gastritis, peptic ulcers, and gastric adenocarcinoma, making the 50S subunit a high-priority target for eradication therapies [11, 12]. However, the efficacy of targeting this subunit is increasingly compromised by the emergence of point mutations in the 23S rRNA gene, such as A2142G and A2143G, which confer high-level resistance to macrolides [1, 2]. Consequently, monitoring these genetic biomarkers is essential for tailoring effective treatment regimens and addressing the global challenge of antibiotic-resistant H. pylori [12, 15].

Other names

50S ribosomeLarge ribosomal subunit50S subunitProkaryotic 50S ribosomal subunit

Drugs targeting the 50S ribosomal subunit inhibit bacterial protein synthesis by binding to specific sites within the 23S rRNA, such as the peptidyl transferase center or the nascent peptide exit tunnel, thereby blocking peptide bond formation or polypeptide elongation [4, 8].