tmRNA-SmpB complex mimics native aminoacyl-tRNAs in the A site of stalled ribosomes

Kimberley Cheng, Natalia Ivanova, Sjors H. W. Scheres, Michael Y. Pavlov, Jose Maria Carazo, Hans Hebert, Mans Ehrenberg, Martin Lindahl

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskriftPeer review

Sammanfattning

Bacterial ribosomes stalled on faulty, often truncated, mRNAs lacking stop codons are rescued by trans-translation. It relies on an RNA molecule (tmRNA) capable of replacing the faulty mRNA with its own open reading frame (ORF). Translation of tmRNA ORF results in the tagging of faulty protein for degradation and its release from the ribosome. We used single-particle cryo-electron microscopy to visualize tmRNA together with its helper protein SmpB on the 70S Escherichia coli ribosome in states subsequent to GTP hydrolysis on elongation factor Tu (EF-Tu). Three-dimensional reconstruction and heterogeneity analysis resulted in a 15 A resolution structure of the tmRNA-SmpB complex accommodated in the A site of the ribosome, which shows that SmpB mimics the anticodon- and D-stem of native tRNAs missing in the tRNA-like domain of tmRNA. We conclude that the tmRNA-SmpB complex accommodates in the ribosomal A site very much like an aminoacyl-tRNA during protein elongation. (C) 2009 Elsevier Inc. All rights reserved.
Originalspråkengelska
Sidor (från-till)342-348
TidskriftJournal of Structural Biology
Volym169
Nummer3
DOI
StatusPublished - 2010

Ämnesklassifikation (UKÄ)

  • Biologiska vetenskaper

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