Visualizing the transfer-messenger RNA as the ribosome resumes translation

Fu, Jie; Hashem, Yaser; Wower, Iwona K.; Lei, Jianlin; Liao, Hstau Y.; Zwieb, Christian W; Wower, Jacek; Frank, Joachim

doi:10.1038/emboj.2010.255

Cited by 39 publications

(55 citation statements)

References 44 publications

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“…A second possibility is that K 131 GKK affects the placement of the tmRNA template within the decoding center. We previously reported that SmpB plays a role in selecting the reading frame on tmRNA (Watts et al 2009), a finding later confirmed by structural studies (Fu et al 2010;Weis et al 2010). Residues Tyr24 and Ala130 were implicated in this process; mutation of these residues alters the reading frame on tmRNA.…”

mentioning

confidence: 53%

The role of SmpB and the ribosomal decoding center in licensing tmRNA entry into stalled ribosomes

Miller¹,

Li²,

Cazier³

et al. 2011

RNA

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In bacteria, stalled ribosomes are recycled by a hybrid transfer-messenger RNA (tmRNA). Like tRNA, tmRNA is aminoacylated with alanine and is delivered to the ribosome by EF-Tu, where it reacts with the growing polypeptide chain. tmRNA entry into stalled ribosomes poses a challenge to our understanding of ribosome function because it occurs in the absence of a codonanticodon interaction. Instead, tmRNA entry is licensed by the binding of its protein partner, SmpB, to the ribosomal decoding center. We analyzed a series of SmpB mutants and found that its C-terminal tail is essential for tmRNA accommodation but not for EF-Tu activation. We obtained evidence that the tail likely functions as a helix on the ribosome to promote accommodation and identified key residues in the tail essential for this step. In addition, our mutational analysis points to a role for the conserved K 131 GKK tail residues in trans-translation after peptidyl transfer to tmRNA, presumably EF-G-mediated translocation or translation of the tmRNA template. Surprisingly, analysis of A1492, A1493, and G530 mutants reveals that while these ribosomal nucleotides are essential for normal tRNA selection, they play little to no role in peptidyl transfer to tmRNA. These studies clarify how SmpB interacts with the ribosomal decoding center to license tmRNA entry into stalled ribosomes.

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mentioning

confidence: 53%

The role of SmpB and the ribosomal decoding center in licensing tmRNA entry into stalled ribosomes

Miller¹,

Li²,

Cazier³

et al. 2011

RNA

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“…Since trans-translation is missing in the eukaryotes, these drugs should have reduced side effects on the cells and metabolisms of the patient. 60,62 E-site translocation and ribosome exit. The model presented here lends support to a mechanism in which the next transition of tmRNA-SmpB from the P-to the E-site would follow the same dynamics (Fig.…”

Section: ©2 0 1 1 L a N D E S B I O S C I E N C E D O N O T D I S Tmentioning

confidence: 99%

“…2d), especially those required for the transition from the A-to the P-site. 60,62 The translocation step implies dynamical motions of tmRNA-SmpB but also of the ribosome to (a) allow the complex to cross the hurdles between the A and P-sites (b) swap the mRNA templates (c) select the correct resume codon and maintain the reading frame on tmRNA.…”

Section: Rna Biology Volume 8 Issuementioning

confidence: 99%

SmpB as the handyman of tmRNA during trans-translation

Felden¹,

Gillet²

2011

RNA Biology

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“…These complexes are perhaps easier to form in vitro. However, as we discussed in our original publication, 31 the insertion of the MS2 hairpin in our tmRNA construct might have over-stabilized the helix 5 that contains part of the ORF, resulting in the vast majority of our in vivo-formed complexes being stalled at the resume state. Thus, to form the complex that depicts later stages of trans-translation in vivo, we could probably insert one or more codons into the single-stranded part of the ORF.…”

confidence: 97%

“…The cryo-EM structure of the tmRNA-ribosome complex in the resume state (the state in which the TLD has moved to the ribosomal P site and translation is ready to resume on the ORF of the tmRNA), obtained independently by our group and the Gillet group, addressed both of these questions. 19,31 The two structures, published back-toback, are from two different organisms, E. coli (our group) and T. thermophilus (the Gillet group). Our complex was formed in vivo.…”

confidence: 99%