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

The Helicobacter pylori 50S ribosomal subunit is the larger component of the bacterial 70S ribosome, essential for protein synthesis. It functions by catalyzing peptide bond formation via its peptidyl transferase center and providing a tunnel for the nascent polypeptide chain to exit [PubMed: 11133755]. The subunit is composed of 23S ribosomal RNA (rRNA), 5S rRNA, and approximately 33 ribosomal proteins. It serves as a major therapeutic target for several classes of antibiotics, most notably macrolides like clarithromycin, which are used in first-line therapy for H. pylori eradication [StatPearls: Helicobacter Pylori]. These drugs bind to the 23S rRNA, obstructing the exit tunnel and halting translation. H. pylori infection is a primary cause of chronic gastritis and peptic ulcer disease, and it is a significant risk factor for gastric adenocarcinoma. The clinical utility of targeting the 50S subunit is currently threatened by the global rise of antibiotic resistance, often caused by point mutations in the 23S rRNA gene [PubMed: 25631126]. Monitoring these mutations is vital for selecting effective treatment regimens and improving patient outcomes.

Other names

Large ribosomal subunit50S subunit23S ribosomal RNA5S ribosomal RNAPeptidyl transferase center

Antibiotics targeting the 50S ribosomal subunit, such as macrolides, bind to the 23S rRNA component at the peptidyl transferase center or the nascent peptide exit tunnel. This binding physically blocks the elongation of the polypeptide chain, thereby inhibiting bacterial protein synthesis and resulting in bacteriostatic or bactericidal effects [StatPearls: Clarithromycin; PubMed: 11133755].