[Conformational transitions in tRNA fMet from E. coli induced by monovalent and divalent ions].

Conformational transitions in tRNAfMet E. coli the initiator tRNA in bacterial systems and in some other individual tRNAs have been studied as a function of monovalent and divalent ion concentrations. By measuring the extent of energy transfer between dye molecules adsorbed on tRNAs and by study of adsorption isotherms of dyes on tRNAs conclusion has been drawn about the similarity of conformational state of all tRNAs studied at low ionic strength (mu 0.01). A conformational change in tRNA, produced by an addition of Mg2+ and Na+ ions results in more than two fold decrease of the strong binding sites for dyes. A marked difference in the adsorption properties of tRNAfMet in comparison with other investigated tRNAs were found. The tRNAfMet was the only tRNA species that did not form the strong type of complexes with dyes at high ionic strength