eEF3 promotes late stages of tRNA translocation on the ribosome

Namit Ranjan, Agnieszka A. Pochopien, Colin Chih Chien Wu, Bertrand Beckert, Sandra Blanchet, Rachel Green, Marina V. Rodnina, Daniel N. Wilson

Research output: Contribution to journalArticlepeer-review

Abstract

In addition to the conserved translation elongation factors eEF1A and eEF2, fungi require a third essential elongation factor, eEF3. While eEF3 has been implicated in tRNA binding and release at the A and E sites, its exact mechanism of action is unclear. Here we show that eEF3 acts at the mRNA–tRNA translocation step by promoting the dissociation of the tRNA from the E site, but independent of aminoacyl-tRNA recruitment to the A site. Depletion of eEF3 in vivo leads to a general slow-down in translation elongation due to accumulation of ribosomes with an occupied A site. Cryo-EM analysis of ex vivo eEF3-ribosome complexes shows that eEF3 facilitates late steps of translocation by favoring nonrotated ribosomal states as well as by opening the L1 stalk to release the E-site tRNA. Additionally, our analysis provides structural insights into novel translation elongation states, enabling presentation of a revised yeast translation elongation cycle.

Original languageEnglish (US)
JournalUnknown Journal
DOIs
StatePublished - Jul 1 2020

Keywords

  • ABC ATPase
  • Cryo-EM
  • E-site tRNA
  • EEF3
  • L1 stalk
  • Translation elongation
  • Translocation
  • Yeast

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • Immunology and Microbiology(all)
  • Neuroscience(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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