Structure of mammalian eIF3 in the context of the 43S preinitiation complex

Article

关键词: EUKARYOTIC TRANSLATION INITIATION;    MESSENGER-RNA RECRUITMENT;    PARTICLE ELECTRON CRYOMICROSCOPY;    CRYOELECTRON MICROSCOPY;    RECOGNITION MOTIF;    26S PROTEASOME;    MOLECULAR-DYNAMICS;    RIBOSOMAL-SUBUNIT;    CRYSTAL-STRUCTURE;    COP9 SIGNALOSOME;   

DOI  :  10.1038/nature14891

来源: SCIE

【 摘 要 】

During eukaryotic translation initiation, 43S complexes, comprising a 40S ribosomal subunit, initiator transfer RNA and initiation factors (eIF) 2, 3, 1 and 1A, attach to the 59-terminal region of messenger RNA and scan along it to the initiation codon. Scanning on structured mRNAs also requires the DExH-box protein DHX29. Mammalian eIF3 contains 13 subunits and participates in nearly all steps of translation initiation. Eight subunits having PCI (proteasome, COP9 signalosome, eIF3) or MPN (Mpr1, Pad1, amino-terminal) domains constitute the structural core of eIF3, to which five peripheral subunits are flexibly linked. Here we present a cryo-electron microscopy structure of eIF3 in the context of the DHX29-bound 43S complex, showing the PCI/MPN core at,6 angstrom resolution. It reveals the organization of the individual subunits and their interactions with components of the 43S complex. We were able to build near-complete polyalanine-level models of the eIF3 PCI/MPN core and of two peripheral subunits. The implications for understanding mRNA ribosomal attachment and scanning are discussed.

【 授权许可】

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