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Updated: Jun 10, 2026

Isolation of Translating Ribosomes Containing Peptidyl-tRNAs for Functional and Structural Analyses
Published on: February 25, 2011
Structural rearrangements of the ribosome at the tRNA proofreading step
Lasse Jenner1, Natalia Demeshkina, Gulnara Yusupova
1Département de Biologie et de Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.
Abstract:
Discrimination of tRNA on the ribosome occurs in two consecutive steps: initial selection and proofreading. Here we propose a proofreading mechanism based on comparison of crystal structures of the 70S ribosome with an empty A site or with the A site occupied by uncharged cognate or near-cognate tRNA. We observe that ribosomal proteins S13, S19, L16, L25, L27 and L31 are actively involved in the proofreading of tRNA. We suggest that proofreading begins with the monitoring of the entire anticodon loop of tRNA by nucleotides from 16S rRNA (helices 18 and 44) of the small subunit and 23S rRNA (helix 69) of the large subunit with involvement of magnesium ions. Subsequently, the elbow region is scanned by rRNA (helices 38 and 89) and proteins from the large subunit determining whether to accommodate the acceptor end of tRNA in the peptidyl transferase center or not.
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