title: Release of polypeptide chain initiation factor IF-2 during initiation complex formation.
abstract: Polypeptide chain initiation factor IF-2 binds to 30S ribosomal subunits. This binding is enhanced by IF-1 and IF-3. During GTP-dependent formation of a 70S initiation complex, IF-2 is released from the ribosome. During 70S initiation complex formation dependent on the methylene analogue of GTP, GMPPCH(2)P, IF-2 is not released, but remains bound to the 70S ribosome. This result suggests that IF-2 release requires GTP hydrolysis. In agreement with this presumed requirement, IF-2 functions catalytically with GTP, but stoichiometrically with GMPPCH(2)P, in bringing about 70S initiation complex formation.
mesh_terms: D002499:Centrifugation, Density Gradient; D004926:Escherichia coli / Q000378:metabolism; D006150:Guanine Nucleotides / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D008715:Methionine; D010442:Peptide Chain Initiation, Translational; D010448:Peptide Initiation Factors / Q000032:analysis; D011119:Polynucleotides / Q000378:metabolism; D011485:Protein Binding; D012343:RNA, Transfer / Q000378:metabolism; D012270:Ribosomes / Q000032:analysis / Q000378:metabolism; D014316:Tritium
chemical_list: D006150:Guanine Nucleotides; D010448:Peptide Initiation Factors; D011119:Polynucleotides; D014316:Tritium; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D008715:Methionine