CHEMICAL MODIFICATION OF PIG LIVER INITIATION FACTOR EIF-2 WITH N-ETHYLMALEIMIDE. AMINO ACID SEQUENCES AROUND THE N-ETHYLMALEIMIDE-REACTIVE SULFHYDRYL GROUPS AND THE EFFECT OF GDP ON THE MODIFICATION

摘要: The activity of eukaryotic initiation factor eIF-2 as to the formation ternary complex, GTP Met-tRNA(f), is inhibited by N-ethylmaleimide. Our preparation pig liver contained alpha and gamma subunits was more than 90% Using our eIF-2, we determined sequences around N-ethylmaleimide-reactive sulfhydryl groups, studied effect GDP on modification that NEM [3H]GDP binding, examined protective against inhibition complex Both native [14C]N-ethylmaleimide-reactive groups. One group in subunit 4 were subunit. sequence peptide be: Ala-Gly-Leu-Asn-Cys-Ser-Thr-Glu-Thr-Met-Pro-Ile. Two four groups highly reactive, their being: Ile-Val-Leu-Thr-Asn-Pro-Val-Cys-Thr-Glu-Val-Gly-Glu-Lys (gamma 1); Ser-Cys-Gly-Ser-Ser-Thr-Pro-Asp-Glu-Phe-Pro-Thr-Asp-Ile-Pro-Gly-Thr-Lys 3a). Peptide 3a consensus element (AspXaaXaaGly) GTP-binding proteins. With preincubation with GDP, incorporation [14C]N-ethylmaleimide into reduced 40% control level, but 14C-incorporation did not change.(ABSTRACT TRUNCATED AT 250 WORDS)