title: The involvement of a complex between formylmethionyl-tRNA and initiation factor IF-2 in prokaryotic initiation.
abstract: A complex between initiation factor IF-2 and fMet-tRNA can be formed under ionic conditions, which are optimal for initiation complex formation. The complex can be retained on cellulose nitrate filters after fixing with glutaraldehyde. The IF-2 - FMet-tRNA complex formation is not influenced by GTP and GDP. Other nucleoside di of triphosphates also have no effect. Evidence is presented that this complex acts as an intermediate in polypeptide chain initiation. The IF-2 - fMet-tRNA complex formation is not influenced by initiation factors IF-1 and IF-3. The binary complex can be bound to the 30-S subunit in the absence of GTP, which indicates that there is no concomittant binding of the IF-2 - fMet-tRNA complex and the nucleotide moiety to the 30-S subunit. The binding of the binary complex is stimulated by GTP. The influence of some inhibitors of initiation on the IF-2 - fMet-tRNA complex formation has been tested. Aurin tricarboxylic acid appeared to be a strong inhibitor, whereas the sulfhydryl reagents N-ethylmaleimide and p-chloromercuribenzoate had no effect.
mesh_terms: D001312:Aurintricarboxylic Acid / Q000494:pharmacology; D002729:Chloromercuribenzoates / Q000494:pharmacology; D003090:Coliphages / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D005033:Ethylmaleimide / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D007700:Kinetics; D046911:Macromolecular Substances; D008274:Magnesium / Q000494:pharmacology; D009239:N-Formylmethionine; D010442:Peptide Chain Initiation, Translational; D010448:Peptide Initiation Factors; D011485:Protein Binding; D012343:RNA, Transfer / Q000378:metabolism; D012265:Ribonucleotides / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D013329:Structure-Activity Relationship; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D002729:Chloromercuribenzoates; D046911:Macromolecular Substances; D010448:Peptide Initiation Factors; D012265:Ribonucleotides; D009239:N-Formylmethionine; D001312:Aurintricarboxylic Acid; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D013752:Tetracycline; D008274:Magnesium; D005033:Ethylmaleimide