Amino acid sequence analysis of the β- and γ-subunits of eukaryotic initiation factor eIF-2. Identification of regions interacting with GTP

Ulrich Axel Bommer, Regine Kraft, Teymuras V. Kurzchalia, Nigel T. Price, Christopher G. Proud

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By affinity labelling using two different GTP photoaffinity analogues we previously demonstrated that both the ß- and γ-subunits of eukaryotic initiation factor eIF-2 are involved in GTP binding (Bommer, U.-A. and Kurzchalia, T.V. (1989) FEBS Lett. 244, 323-327). We have now applied the same method in combination with CNBr cleavage and microsequence analysis in order investigate which part of the polypeptide chain of eIF-2ß is in close contact to the bound GTP. From the three main CNBr fragments of eIF-2ß, the C-terminal one was found to be labelled by the applied GTP photoaffinity analogue, Guo(2′,3′-TDBH)ppp. Because the cDNA sequence of the γ-subunit of eIF-2 has not yet been published and because cDNA sequence analysis of eIF-2ß revealed only two out of three consensus sequence elements of a GTP-binding domain, we also sequenced the CNBr fragments of eIF-2γ. In this way, sequences containing about 50 amino acid residues were obtained. Taken together with the recently published N-terminal sequences of tryptic peptides of eIF-2γ from pig liver (Suzuki et al. 1990, J. Biochem. 108, 635-641), about 30% of the total sequence is now known. One fo teh CNBr frgments from rabbit eIF-2γ contains a sequence (AXXAXXGK) which in several respects resembles that of the consensus sequence element absent from the ß-subunit.

Original languageEnglish
Pages (from-to)308-315
Number of pages8
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Issue number3
Publication statusPublished or Issued - 20 Sept 1991
Externally publishedYes


  • Affinity labelling
  • Eukaryotic initiation factor
  • GTP binding
  • Protein synthesis
  • Sequence analysis

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology

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