A structural inventory of native ribosomal ABCE1-43S pre-initiation complexes

Hanna Kratzat, Timur Mackens-Kiani, Michael Ameismeier, Mia Potocnjak, Jingdong Cheng, Estelle Dacheux, Abdelkader Namane, Otto Berninghausen, Franz Herzog, Micheline Fromont-Racine, Thomas Becker, Roland Beckmann

Publikation: Beitrag in FachzeitschriftArtikelBegutachtung

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.

OriginalspracheEnglisch
Aufsatznummere105179
Seiten (von - bis)e105179
FachzeitschriftEMBO Journal
Jahrgang40
Ausgabenummer1
DOIs
PublikationsstatusVeröffentlicht - 4 Jän. 2021
Extern publiziertJa

Forschungsfelder

  • Chemical Crosslinking
  • Mass spectrometry
  • Structural Biology

IMC Forschungsschwerpunkte

  • Medical biotechnology

ÖFOS 2012 - Österreichischen Systematik der Wissenschaftszweige

  • 106037 Proteomik
  • 106041 Strukturbiologie
  • 106044 Systembiologie

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