Structure of the Thermus thermophilus 30S ribosomal subunit in the presence of crystallographically disordered codon and near-cognate transfer RNA anticodon stem-loop mismatched at the second codon position
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 c ...
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.
Related Citations:
Recognition of Cognate Transfer RNA by the 30S Ribosomal Subunit Ogle, J.M., Brodersen, D.E., Clemons Jr., W.M., Tarry, M.J., Carter, A.P., Ramakrishnan, V. (2001) Science 292: 897
Structure of the 30S Ribosomal Subunit Wimberly, B.T., Brodersen, D.E., Clemons Jr., W.M., Morgan-Warren, R., Carter, A.P., Vonrhein, C., Hartsch, T., Ramakrishnan, V. (2000) Nature 407: 327
Functional Insights from the Structure of the 30S Ribosomal Subunit and
its Interactions with Antibiotics Carter, A.P., Clemons Jr., W.M., Brodersen, D.E., Wimberly, B.T., Morgan-Warren, R., Ramakrishnan, V. (2000) Nature 407: 340
Organizational Affiliation:
MRC Laboratory of Molecular Biology, Hills Road, CB2 2QH, Cambridge, United Kingdom.
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