6GSM

Structure of a partial yeast 48S preinitiation complex in open conformation.

This is a non-PDB format compatible entry.

Replaces:  3JAQ

Summary for 6GSM

• Entry DOI: 10.2210/pdb6gsm/pdb
• Related: 3JAP 3JAQ
• EMDB information: 0057 3048 3049
• Descriptor: Met-tRNAi, 40S ribosomal protein S6, 40S ribosomal protein S7, ... (51 entities in total)
• Functional Keywords: ribosome, translation, initiation factors, 40s, eif1a, eif3, eif2, trnai, 48s pic, small ribosome subunit
• Biological source: Saccharomyces cerevisiae S288C; More
• Total number of polymer chains: 47
• Total formula weight: 1532958.88

Authors

Llacer, J.L.,Hussain, T.,Gordiyenko, Y.,Ramakrishnan, V. (deposition date: 2018-06-14, release date: 2019-07-31, Last modification date: 2024-09-25)

Primary citation

Llacer, J.L.,Hussain, T.,Dong, J.,Villamayor, L.,Gordiyenko, Y.,Hinnebusch, A.G.
Large-scale movement of eIF3 domains during translation initiation modulate start codon selection.
Nucleic Acids Res., 2021

PubMed Abstract: The eukaryotic initiation factor 3 (eIF3) complex is involved in every step of translation initiation, but there is limited understanding of its molecular functions. Here, we present a single particle electron cryomicroscopy (cryo-EM) reconstruction of yeast 48S ribosomal preinitiation complex (PIC) in an open conformation conducive to scanning, with core subunit eIF3b bound on the 40S interface near the decoding center in contact with the ternary complex eIF2·GTP·initiator tRNA. eIF3b is relocated together with eIF3i from their solvent interface locations observed in other PIC structures, with eIF3i lacking 40S contacts. Re-processing of micrographs of our previous 48S PIC in a closed state also suggests relocation of the entire eIF3b-3i-3g-3a-Cter module during the course of initiation. Genetic analysis indicates that high fidelity initiation depends on eIF3b interactions at the 40S subunit interface that promote the closed PIC conformation, or facilitate the relocation of eIF3b/eIF3i to the solvent interface, on start codon selection.

PubMed: 34648019
DOI: 10.1093/nar/gkab908

Experimental method

ELECTRON MICROSCOPY (5.15 Å)