Regulation of binding of initiator tRNA to eukaryotic initiation factor eIF-2. Effects of the haem-controlled repressor on the kinetics of ternary complex formation.
Ternary complex formation was studied in reticulocyte lysate supernatants and using rat liver eukaryotic initiation factor-2 (eIF-2) preparations. Haem-deficiency reduced the rate of formation of ternary (Met-tRNAf . GTP . eIF-2) complexes by the eIF-2 in reticulocyte supernatants, the reduction being more marked when complex formation was assayed in the absence of GTP-regenerating capacity. Pretreatment with the haem-controlled repressor (HCR) reduced the rate of ternary complex formation by crude (liver) eIF-2. In contrast, complex formation by an almost homogeneous eIF-2 preparation was unaffected by HCR: sensitivity to HCR was however restored by a factor which catalyses exchange of guanine nucleotides bound to eIF-2.
D000818:Animals; D015852:Eukaryotic Initiation Factor-2; D006160:Guanosine Triphosphate / Q000378:metabolism; D006418:Heme / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D010448:Peptide Initiation Factors / Q000235:genetics*; D014176:Protein Biosynthesis / Q000187:drug effects*; D011506:Proteins / Q000235:genetics*; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics*; D011817:Rabbits; D051381:Rats; D012156:Reticulocytes / Q000378:metabolism
D015852:Eukaryotic Initiation Factor-2; D010448:Peptide Initiation Factors; D011506:Proteins; D012346:RNA, Transfer, Amino Acyl; C026464:tRNA(m)(Met), methionine-; D006418:Heme; D006160:Guanosine Triphosphate