The RNA-binding properties of protein synthesis initiation factor eIF-2

Andrea Flynn, Ivan N. Shatsky, Christopher G. Proud, Ann Kaminski

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Protein synthesis initiation factor eIF-2 bound ATP in the presence or absence of Mg2+ ions. ATP impaired the binding of GTP or GDP to eIF-2. However, excess GTP did not significantly decrease the binding of ATP to eIF-2, suggesting eIF-2 has distinct ATP and GTP binding sites. Highly purified eIF-2 can bind mRNA, and this did not require the mRNA to be capped. mRNA binding was saturable, and maximal binding corresponded to about 0.4 mol mRNA bound per mol eIF-2. GTP, and, at lower concentrations, GDP, inhibited the binding of mRNA to eIF-2. In addition, ATP and other nucleoside triphosphates decreased mRNA binding. The implications of these findings for the structure and function of eIF-2 are discussed. Preparations of eIF-2 deficient in the β-subunit showed reduced ability to bind mRNA, suggesting that while it is not essential for mRNA binding, this subunit is involved in the interaction. Consistent with this is the observation that ultraviolet crosslinking of mRNA to eIF-2 resulted primarily in labelling of the β-subunit. Subsequent analysis revealed that mRNA was cross-linked to the C-terminal region of eIF-2b which contains a putative Zn-finger structure.

Original languageEnglish
Pages (from-to)293-301
Number of pages9
JournalBBA - Gene Structure and Expression
Volume1219
Issue number2
DOIs
Publication statusPublished - 18 Oct 1994

Keywords

  • Cross-linking
  • RNA binding
  • Zinc finger
  • eIF-2

ASJC Scopus subject areas

  • Structural Biology
  • Biophysics
  • Biochemistry
  • Genetics

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