The binding mechanism of eIF2β with its partner proteins, eIF5 and eIF2Bε

Zuoqi Gai, Yumie Kitagawa, Yoshikazu Tanaka, Nobutaka Shimizu, Keisuke Komoda, Isao Tanaka, Min Yao

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The eukaryotic translation initiation factor eIF2 delivers Met-tRNAiMet to the ribosomal small subunit in GTP-bound form associated with eIF1, eIF1A, eIF3 and eIF5, and dissociates together with eIF5 as eIF5-eIF2-GDP complex from the ribosomal small subunit after formation of start codon-anticodon base pairing between Met-tRNAiMet and mRNA. The inactive form eIF2-GDP is then exchanged for the active form eIF2-GTP by eIF2B for further initiation cycle. Previous studies showed that the C-terminal domains of eIF5 (eIF5-CTD) and eIF2Bε (eIF2Bε-CTD) have a common eIF2β-binding site for interacting with an N-terminal region of eIF2β (eIF2β-NTD). Here we have reconstructed the complexes of (eIF5-CTD)-(eIF2β-NTD) and (eIF2Bε-CTD)-(eIF2β-NTD) i. n vitro, and investigated binding mechanism by circular dichroism spectroscopy and small angle X-ray scattering in solution. The results showed the conformation of eIF2β-NTD was changed when bound to partner proteins, whereas the structures of eIF5-CTD and eIF2Bε-CTD were similar in both isolated and complex states. We propose that eIF2β-NTD works as an intrinsically disordered domain which is disorder in the isolated state, but folds into a definite structure when bound to its partner proteins. Such flexibility of eIF2β-NTD is expected to be responsible for its binding capability.

Original languageEnglish
Pages (from-to)515-519
Number of pages5
JournalBiochemical and Biophysical Research Communications
Issue number3
Publication statusPublished - 2012 Jul 6


  • EIF2
  • EIF2B
  • EIF5
  • Intrinsically disordered domain
  • Translation initiation


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