7A09

Structure of a human ABCE1-bound 43S pre-initiation complex - State III

This is a non-PDB format compatible entry.

Summary for 7A09

• Entry DOI: 10.2210/pdb7a09/pdb
• Related: 6ZVJ 6zce 6zu9 7a1g
• EMDB information: 11602
• Descriptor: 40S ribosomal protein SA, 40S ribosomal protein S9, 40S ribosomal protein S11, ... (61 entities in total)
• Functional Keywords: translation, initiation, ribosome recycling, abc proteins, ribosome
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 54
• Total formula weight: 2159875.27

Authors

Kratzat, H.,Mackens-Kiani, T.,Ameismeier, A.,Cheng, J.,Berninghausen, O.,Becker, T.,Beckmann, R. (deposition date: 2020-08-07, release date: 2020-10-14, Last modification date: 2021-01-13)

Primary citation

Kratzat, H.,Mackens-Kiani, T.,Ameismeier, M.,Potocnjak, M.,Cheng, J.,Dacheux, E.,Namane, A.,Berninghausen, O.,Herzog, F.,Fromont-Racine, M.,Becker, T.,Beckmann, R.
A structural inventory of native ribosomal ABCE1-43S pre-initiation complexes.
Embo J., 40:e105179-e105179, 2021

PubMed Abstract: In eukaryotic translation, termination and ribosome recycling phases are linked to subsequent initiation of a new round of translation by persistence of several factors at ribosomal sub-complexes. These comprise/include the large eIF3 complex, eIF3j (Hcr1 in yeast) and the ATP-binding cassette protein ABCE1 (Rli1 in yeast). The ATPase is mainly active as a recycling factor, but it can remain bound to the dissociated 40S subunit until formation of the next 43S pre-initiation complexes. However, its functional role and native architectural context remains largely enigmatic. Here, we present an architectural inventory of native yeast and human ABCE1-containing pre-initiation complexes by cryo-EM. We found that ABCE1 was mostly associated with early 43S, but also with later 48S phases of initiation. It adopted a novel hybrid conformation of its nucleotide-binding domains, while interacting with the N-terminus of eIF3j. Further, eIF3j occupied the mRNA entry channel via its ultimate C-terminus providing a structural explanation for its antagonistic role with respect to mRNA binding. Overall, the native human samples provide a near-complete molecular picture of the architecture and sophisticated interaction network of the 43S-bound eIF3 complex and the eIF2 ternary complex containing the initiator tRNA.

PubMed: 33289941
DOI: 10.15252/embj.2020105179

Experimental method

ELECTRON MICROSCOPY (3.5 Å)