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Title | Translational initiation factor eIF5 replaces eIF1 on the 40S ribosomal subunit to promote start-codon recognition. |
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Journal, issue, pages | Elife, Vol. 7, Year 2018 |
Publish date | Nov 30, 2018 |
![]() | Jose Luis Llácer / Tanweer Hussain / Adesh K Saini / Jagpreet Singh Nanda / Sukhvir Kaur / Yuliya Gordiyenko / Rakesh Kumar / Alan G Hinnebusch / Jon R Lorsch / V Ramakrishnan / ![]() ![]() ![]() ![]() |
PubMed Abstract | In eukaryotic translation initiation, AUG recognition of the mRNA requires accommodation of Met-tRNA in a 'P' state, which is antagonized by the factor eIF1. eIF5 is a GTPase activating protein (GAP) ...In eukaryotic translation initiation, AUG recognition of the mRNA requires accommodation of Met-tRNA in a 'P' state, which is antagonized by the factor eIF1. eIF5 is a GTPase activating protein (GAP) of eIF2 that additionally promotes stringent AUG selection, but the molecular basis of its dual function was unknown. We present a cryo-electron microscopy (cryo-EM) reconstruction of a yeast 48S pre-initiation complex (PIC), at an overall resolution of 3.0 Å, featuring the N-terminal domain (NTD) of eIF5 bound to the 40S subunit at the location vacated by eIF1. eIF5 interacts with and allows a more accommodated orientation of Met-tRNA. Substitutions of eIF5 residues involved in the eIF5-NTD/tRNA interaction influenced initiation at near-cognate UUG codons and the closed/open PIC conformation in vitro, consistent with direct stabilization of the codon:anticodon duplex by the wild-type eIF5-NTD. The present structure reveals the basis for a key role of eIF5 in start-codon selection. |
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Methods | EM (single particle) |
Resolution | 3.02 - 3.53 Å |
Structure data | EMDB-4327: Structure of a partial yeast 48S preinitiation complex with eIF5 N-terminal domain (Map C1) EMDB-4328: Structure of a partial yeast 48S preinitiation complex with eIF5 N-terminal domain (Map 1) ![]() EMDB-4329: ![]() EMDB-4330: ![]() EMDB-4331: |
Chemicals | ![]() ChemComp-MG: ![]() ChemComp-ZN: ![]() ChemComp-MET: ![]() ChemComp-GCP: |
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