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-Structure paper
Title | Molecular basis for the ribosome functioning as an L-tryptophan sensor. |
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Journal, issue, pages | Cell Rep, Vol. 9, Issue 2, Page 469-475, Year 2014 |
Publish date | Oct 23, 2014 |
![]() | Lukas Bischoff / Otto Berninghausen / Roland Beckmann / ![]() |
PubMed Abstract | Elevated levels of the free amino acid L-tryptophan (L-Trp) trigger expression of the tryptophanase tnaCAB operon in E. coli. Activation depends on tryptophan-dependent ribosomal stalling during ...Elevated levels of the free amino acid L-tryptophan (L-Trp) trigger expression of the tryptophanase tnaCAB operon in E. coli. Activation depends on tryptophan-dependent ribosomal stalling during translation of the upstream TnaC peptide. Here, we present a cryoelectron microscopy (cryo-EM) reconstruction at 3.8 Å resolution of a ribosome stalled by the TnaC peptide. Unexpectedly, we observe two L-Trp molecules in the ribosomal exit tunnel coordinated within composite hydrophobic pockets formed by the nascent TnaC peptide and the tunnel wall. As a result, the peptidyl transferase center (PTC) adopts a distinct conformation that precludes productive accommodation of release factor 2 (RF2), thereby inducing translational stalling. Collectively, our results demonstrate how the translating ribosome can act as a small molecule sensor for gene regulation. |
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Methods | EM (single particle) |
Resolution | 3.8 Å |
Structure data | |
Chemicals | ![]() ChemComp-MG: ![]() ChemComp-ZN: ![]() ChemComp-TRP: ![]() ChemComp-HOH: |
Source |
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![]() | RIBOSOME / TNAC / TRANSLATION REGULATION |