Bacterial 16S ribosomal RNA decoding site (16S rRNA A-site)

The bacterial 16S ribosomal RNA (rRNA) decoding region, specifically the aminoacyl-tRNA binding site (A-site), is a fundamental component of the 30S ribosomal subunit essential for translational fidelity [Vicens, Q., & Westhof, E. (2001). Structure]. During protein synthesis, this region monitors the complementarity between the mRNA codon and the tRNA anticodon, ensuring that the correct amino acid is added to the growing polypeptide chain [Ogle, J. M., et al. (2001). Science]. When a cognate tRNA binds, highly conserved adenine residues (A1492 and A1493) undergo a conformational change, flipping out of the helix to stabilize the codon-anticodon interaction [Carter, A. P., et al. (2000). Nature]. This site is the primary pharmacological target for aminoglycoside antibiotics, which bind with high affinity to the internal loop of the A-site, forcing the adenine residues into the "on" state regardless of codon-anticodon match [Magnet, S., & Blanchard, J. S. (2005). Chemical Reviews]. This interference leads to significant mistranslation and the production of non-functional or toxic proteins, which eventually causes bacterial cell death [Kohanski, M. A., et al. (2007). Cell]. Resistance to drugs targeting this region often arises through enzymatic modification of the rRNA, such as methylation by 16S rRNA methyltransferases, or mutations that alter the binding pocket [Doi, Y., et al. (2016). Clinical Microbiology Reviews].

Other names

16S ribosomal RNA decoding region30S decoding centerAminoacyl-tRNA binding siteA-site of the 30S subunitDecoding region of the 30S subunit

Aminoglycosides bind to the 16S rRNA A-site, inducing a conformational change in residues A1492 and A1493 that mimics cognate tRNA binding, leading to mistranslation and protein synthesis inhibition [Magnet, S., & Blanchard, J. S. (2005). Chemical Reviews]. Tetracyclines bind to the 30S subunit to sterically block the entry of aminoacyl-tRNA into the A-site [Carter, A. P., et al. (2000). Nature].