Structure of mammalian eIF3 in the context of the 43S preinitiation complex.
Nature
; 525(7570): 491-5, 2015 Sep 24.
Article
in En
| MEDLINE
| ID: mdl-26344199
ABSTRACT
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 5'-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 â¼6 Å 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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Peptide Chain Initiation, Translational
/
Ribosomes
/
Eukaryotic Initiation Factor-3
/
Multiprotein Complexes
Type of study:
Prognostic_studies
Limits:
Humans
Language:
En
Journal:
Nature
Year:
2015
Type:
Article
Affiliation country:
United States