6gsm

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

Loading... Status: waiting for Mol* initialization Structural highlights 6gsm is a 10 chain structure with sequence from Kluyveromyces lactis, Kluyveromyces lactis NRRL Y-1140 and Saccharomyces cerevisiae S288C. This structure supersedes the now removed PDB entry 3jaq. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 1MA, 1MG, 2MG, 5MC, 7MG, 7NO, GCP, H2U, M2G, MG, RIA, T6A, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RSSA_KLULA Required for the assembly and/or stability of the 40S ribosomal subunit. Required for the processing of the 20S rRNA-precursor to mature 18S rRNA in a late step of the maturation of 40S ribosomal subunits. Publication Abstract from PubMed 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. Large-scale movement of eIF3 domains during translation initiation modulate start codon selection.,Llacer JL, Hussain T, Dong J, Villamayor L, Gordiyenko Y, Hinnebusch AG Nucleic Acids Res. 2021 Oct 14. pii: 6396891. doi: 10.1093/nar/gkab908. PMID:34648019 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosome 3D structures

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