Structural insights into the evolution of late steps of translation initiation in the three domains of life

Biochimie. 2024 Feb:217:31-41. doi: 10.1016/j.biochi.2023.02.002. Epub 2023 Feb 9.


In eukaryotes and in archaea late steps of translation initiation involve the two initiation factors e/aIF5B and e/aIF1A. These two factors are also orthologous to the bacterial IF2 and IF1 proteins, respectively. Recent cryo-EM studies showed how e/aIF5B and e/aIF1A cooperate on the small ribosomal subunit to favor the binding of the large ribosomal subunit and the formation of a ribosome competent for elongation. In this review, pioneering studies and recent biochemical and structural results providing new insights into the role of a/eIF5B in archaea and eukaryotes will be presented. Recent structures will also be compared to orthologous bacterial initiation complexes to highlight domain-specific features and the evolution of initiation mechanisms.

Keywords: Initiator tRNA; Late steps of initiation; Ribosome; eIF1A; eIF5B.

Publication types

  • Review

MeSH terms

  • Bacteria / metabolism
  • Eukaryotic Initiation Factor-1* / analysis
  • Eukaryotic Initiation Factor-1* / chemistry
  • Eukaryotic Initiation Factor-1* / metabolism
  • Peptide Initiation Factors* / analysis
  • Peptide Initiation Factors* / chemistry
  • Peptide Initiation Factors* / genetics
  • Ribosomes / metabolism


  • Eukaryotic Initiation Factor-1
  • Peptide Initiation Factors