Initiation of mammalian protein synthesis: dynamic properties of the assembly process in vitro.
Binding of the Met-tRNAMetf . eIf-2 GTP complex to the 40 S ribosomal subunit is the first step in initiation of eukaryotic protein synthesis. The extent of binding and the stability of the complex are enhanced by initiation factors eIF-3 and eIF-4C, AUG and elevated magnesium concentration. The reversibility of reaction steps occurring during the assembly of the initiation complex is measured as the rate of Met-tRNAMetf exchange in the initiation complex and its intermediates. This rate progressively decreases and Met-tRNAMetf binding becomes irreversible upon binding of mRNA. The association of the 40 S Met-tRNAMetf mRNA initiation complex with the 60 S ribosomal subunit is again reversible as long as elongation does not occur.
D000818:Animals; D004355:Drug Stability; D015852:Eukaryotic Initiation Factor-2; D005914:Globins / Q000235:genetics; D006160:Guanosine Triphosphate / Q000378:metabolism*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008433:Mathematics; D010442:Peptide Chain Initiation, Translational / Q000187:drug effects; D010448:Peptide Initiation Factors / Q000235:genetics*; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics*; D012358:RNA, Transfer, Met; D012270:Ribosomes / Q000378:metabolism*
D015852:Eukaryotic Initiation Factor-2; D010448:Peptide Initiation Factors; D011506:Proteins; D012333:RNA, Messenger; D012346:RNA, Transfer, Amino Acyl; D012358:RNA, Transfer, Met; C024988:tRNA, formylmethionine-; D006160:Guanosine Triphosphate; D005914:Globins; D008274:Magnesium