Practice question

Group decoding or monitoring of codon-anticodon matches occurs at small subunit decoding center formed by 16S rRNA in prokaryotes and 18S rRNA in eukaryotes. Core residues A1492, A1493, G530 inspect shape of Watson-Crick pairs in minor groove via A-minor interactions, triggering GTPase activation only for cognate duplexes. Large subunit rRNAs 23S and 28S instead catalyze peptidyl transferase. Thus decoding fidelity segregates to small subunit rRNA, explaining aminoglycoside antibiotics inducing misreading by binding 16S decoding site and stabilizing near-cognate conformations. This refined regulation supports accurate ribosomal assembly, quality control and translational fidelity under diverse physiological conditions and growth states.