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Template:STRUCTURE 1n33

Structure of the Thermus thermophilus 30S ribosomal subunit bound to codon and near-cognate transfer rna anticodon stem-loop mismatched at the second codon position at the a site with paromomycin

Overview

A structural and mechanistic explanation for the selection of tRNAs by the ribosome has been elusive. Here, we report crystal structures of the 30S ribosomal subunit with codon and near-cognate tRNA anticodon stem loops bound at the decoding center and compare affinities of equivalent complexes in solution. In ribosomal interactions with near-cognate tRNA, deviation from Watson-Crick geometry results in uncompensated desolvation of hydrogen-bonding partners at the codon-anticodon minor groove. As a result, the transition to a closed form of the 30S induced by cognate tRNA is unfavorable for near-cognate tRNA unless paromomycin induces part of the rearrangement. We conclude that stabilization of a closed 30S conformation is required for tRNA selection, and thereby structurally rationalize much previous data on translational fidelity.

About this Structure

1N33 is a Protein complex structure of sequences from Thermus thermophilus. Full crystallographic information is available from OCA.

Reference

Selection of tRNA by the ribosome requires a transition from an open to a closed form., Ogle JM, Murphy FV, Tarry MJ, Ramakrishnan V, Cell. 2002 Nov 27;111(5):721-32. PMID:12464183 Page seeded by OCA on Sat May 3 02:01:48 2008