Structural basis for the transition from translation initiation to elongation by an 80S-eIF5B complex.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33024099.
- Also identified by DOI 10.1038/s41467-020-18829-3 and PMC identifier 7538418.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Recognition of a start codon by the initiator aminoacyl-tRNA determines the reading frame of messenger RNA (mRNA) translation by the ribosome. In eukaryotes, the GTPase eIF5B collaborates in the correct positioning of the initiator Met-tRNA<sub>i</sub><sup>Met</sup> on the ribosome in the later stages of translation initiation, gating entrance into elongation. Leveraging the long residence time of eIF5B on the ribosome recently identified by single-molecule fluorescence measurements, we determine the cryoEM structure of the naturally long-lived ribosome complex with eIF5B and Met-tRNA<sub>i</sub><sup>Met</sup> immediately before transition into elongation. The structure uncovers an unexpected, eukaryotic specific and dynamic fidelity checkpoint implemented by eIF5B in concert with components of the large ribosomal subunit.
Medical subject headings
- Eukaryotic Initiation Factors
- Peptide Chain Elongation, Translational
- Peptide Chain Initiation, Translational
- Ribosome Subunits, Large