title: [Photoaffinity modification of Escherichia coli ribosomes by fMet-tRNAf Met derivatives in the 70S initiation complex].
abstract: Photoaffinity labeling of E. coli ribosomes within the 70S initiation complex was studied by using photoreactive derivatives of fMet-tRNAfMet bearing arylazidogroups scattered statistically over guanosine residues. It is shown that fMet-azido-tRNAfMet-II bearing 2 moles of the reagent residues per mole of tRNA (modified in the conditions of stability of tRNA tertiary structure) is fully active in aminoacylation and in the factor-dependent binding with ribosomes to form the 70S initiation complex. Functional activity of fMet-azido-tRNAfMet-I bearing also 2 moles of the reagent residues per mole of tRNA (but modified in conditions of lability of tRNA tertiary structure) decreases up to approximately 45% in aminoacylation and up to 70% in IF-2 X GTP-dependent binding to the ribosomes. Irradiation of complexes 70S ribosome-MS2-RNA-fMet-azido-tRNAfMet results in covalent linking of the tRNA derivative to the ribosomes. Both subunits are labeled, the 30S to a larger extent than 50S. It is shown that fMet-azido-tRNAfMet-II labels proteins S1, S7, S9, L27 whereas fMet-azido-tRNAfMet-1--proteins S1, S3, S5, S9, S14, L1, L2, L7/L12.
mesh_terms: D000345:Affinity Labels; D001386:Azides; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D012358:RNA, Transfer, Met; D012270:Ribosomes / Q000378:metabolism* / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D000345:Affinity Labels; D001386:Azides; D010448:Peptide Initiation Factors; D012329:RNA, Bacterial; D012346:RNA, Transfer, Amino Acyl; D012358:RNA, Transfer, Met; C024988:tRNA, formylmethionine-
vernacular_title: Issledovanie fotoaffinnoĭ modifikatsii ribosom Escherichia coli proizvodnymi fMet-tRNKf Met v sostave 70S kompleksa initsiatsii.