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-Structure paper
Title | Ensemble cryo-EM elucidates the mechanism of translation fidelity. |
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Journal, issue, pages | Nature, Vol. 546, Issue 7656, Page 113-117, Year 2017 |
Publish date | Jun 1, 2017 |
Authors | Anna B Loveland / Gabriel Demo / Nikolaus Grigorieff / Andrei A Korostelev / |
PubMed Abstract | Gene translation depends on accurate decoding of mRNA, the structural mechanism of which remains poorly understood. Ribosomes decode mRNA codons by selecting cognate aminoacyl-tRNAs delivered by ...Gene translation depends on accurate decoding of mRNA, the structural mechanism of which remains poorly understood. Ribosomes decode mRNA codons by selecting cognate aminoacyl-tRNAs delivered by elongation factor Tu (EF-Tu). Here we present high-resolution structural ensembles of ribosomes with cognate or near-cognate aminoacyl-tRNAs delivered by EF-Tu. Both cognate and near-cognate tRNA anticodons explore the aminoacyl-tRNA-binding site (A site) of an open 30S subunit, while inactive EF-Tu is separated from the 50S subunit. A transient conformation of decoding-centre nucleotide G530 stabilizes the cognate codon-anticodon helix, initiating step-wise 'latching' of the decoding centre. The resulting closure of the 30S subunit docks EF-Tu at the sarcin-ricin loop of the 50S subunit, activating EF-Tu for GTP hydrolysis and enabling accommodation of the aminoacyl-tRNA. By contrast, near-cognate complexes fail to induce the G530 latch, thus favouring open 30S pre-accommodation intermediates with inactive EF-Tu. This work reveals long-sought structural differences between the pre-accommodation of cognate and near-cognate tRNAs that elucidate the mechanism of accurate decoding. |
External links | Nature / PubMed:28538735 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.2 - 4.0 Å |
Structure data | EMDB-8615, PDB-5uyk: EMDB-8616, PDB-5uyl: EMDB-8617, PDB-5uym: EMDB-8618, PDB-5uyn: |
Chemicals | ChemComp-GCP: ChemComp-FME: ChemComp-PHE: ChemComp-MG: ChemComp-ZN: ChemComp-LYS: |
Source |
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Keywords | RIBOSOME / ternary complex / EF-Tu / tRNA |