title: [Study on the conformational state of Escherichia coli tRNA-Phe in solution by ESR-spectometry without modulation].
abstract: ESR-spectrometry without modulation of the magnetic field was used for registering the EST spectral line shape (with shape distortion about 0.1 percent) of spin-labeled Escherichia coli tRNAPhe. The analysis of line shape of two different spin-labels in position 8 (S4U) revealed that tRNAPhe in solution always exists as a mixture of at least two conformers, the equilibria between conformers being dependent on pH, concentration of magnesium and the biological state of tRNA (deacylated, aminoacyl- or peptidyl-tRNA). There are no large structural rearrangements upon aminoacylation or peptidylation of tRNA, the observed small changes of spectral line shape are due to the changes in conformational equilibria.
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D009690:Nucleic Acid Conformation; D012329:RNA, Bacterial; D012346:RNA, Transfer, Amino Acyl; D012996:Solutions; D013113:Spin Labels
chemical_list: D012329:RNA, Bacterial; D012346:RNA, Transfer, Amino Acyl; D012996:Solutions; D013113:Spin Labels
vernacular_title: Izuchenie konformatsionnoĭ situatsii v vodnykh rastvorakh spin-mechenoĭ tRNA-Phe iz Escherichia coli bezomduliatsionnym metodom EPR.