Bacterial 16S ribosomal RNA decoding A-site and 23S ribosomal RNA helix 69 (16S rRNA A-site / 23S rRNA H69)

The bacterial ribosome, specifically the 16S rRNA decoding A-site and the 23S rRNA helix 69, serves as a critical target for aminoglycoside antibiotics. The 16S rRNA A-site is located within the 30S ribosomal subunit and is responsible for ensuring the fidelity of mRNA translation by monitoring codon-anticodon pairing (Vicens & Westhof, 2001). Helix 69 (H69) of the 23S rRNA is a highly conserved region of the 50S subunit that forms the essential intersubunit bridge B2a, facilitating communication between the two ribosomal subunits (Wang et al., 2012). Drugs targeting these sites, such as gentamicin and amikacin, bind primarily to the A-site to induce mistranslation and inhibit translocation. Secondary binding to H69 can disrupt ribosome recycling and subunit dynamics, further compromising bacterial viability (StatPearls, 2023). This dual-site interaction effectively halts bacterial protein synthesis, making it a potent mechanism for treating various bacterial infections. However, clinical use is often limited by significant side effects, including nephrotoxicity and ototoxicity. Resistance often emerges through rRNA methylation or enzymatic modification of the drugs, posing a significant therapeutic challenge (NCBI, 2023).

Other names

16S rRNA A-siteHelix 44 of 16S rRNAHelix 69 of 23S rRNAH69Decoding centerIntersubunit bridge B2aAminoglycoside binding site

Aminoglycosides bind to the 16S rRNA A-site to induce mRNA misreading and inhibit translocation; secondary binding to 23S rRNA helix 69 interferes with intersubunit bridge B2a, affecting ribosome recycling and subunit dissociation (Vicens & Westhof, 2001; Wang et al., 2012).