title: [Study of the photoaffinity modification of Escherichia coli ribosomes near the donor tRNA-binding center].
abstract: Affinity labelling of E. coli ribosomes near the donor tRNA-binding (P) site was studied with the use of photoreactive derivatives of tRNAPhe bearing arylazidogroups on N7 atoms of guanine residues (azido-tRNA). UV-irradiation of complexes 70S ribosome.poly(U).azido- tRNA(P-site) and 70S ribosome.poly(U).azido-tRNA(P-site).Phe- tRNAPhe(A-site) resulted in covalent attachment of azido-tRNA to ribosomes, both subunits being labelled. In both cases modification extent of 30S subunit was two-fold than that of the 50S one. It was shown that when the A-site was free the azido-tRNA located in P-site labelled proteins S9, S11, S12, S13, S21 and L14, L27, L31. Azido-tRNA located in P-site when the A-site was occupied with Phe-tRNAPhe labelled proteins S11, S12, S13, S14, S19, L32/L33 and possibly L23, L25. From the comparison of the sets of proteins labelled when A-site was free or occupied a conclusion was drawn that aminoacyl-tRNA located in ribosomal A-site affects the arrangement of deacylated tRNA in P-site. Data obtained allow to propose that proteins S5, S19, S20 and L24, L33 interact with guanine residues important for the tRNA tertiary structure formation.
mesh_terms: D000345:Affinity Labels; D001386:Azides / Q000378:metabolism*; D001665:Binding Sites; D004926:Escherichia coli / Q000378:metabolism*; D011072:Poly U / Q000378:metabolism; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D000345:Affinity Labels; D001386:Azides; D012346:RNA, Transfer, Amino Acyl; D012269:Ribosomal Proteins; C038012:tRNA, azidophenylalanine-; D011072:Poly U
vernacular_title: Issledovanie fotoaffinnoĭ modifikatsii ribosom Escherichia coli vblizi donornogo tRNK-sviazyvaiushchego uchastka.