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

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