Usenko E. Mg2+, Ca2+, Cd2+ and Ni2+ ion effects on conformational equilibrium between single-, double- and three-stranded polynucleotides under conditions close to physiological ones.

Conformational transitions in aqueous solutions of metal complexes of polynucleotides. Set the basic laws of the influence of solution temperature and Mg2+, Ca2+, Cd2+ and Ni2+ ion concentrations on the conformational equilibrium in aqueous solutions of polynucleotides of different levels of structural organization, determine the physical nature of structural transitions induced by these ions and to determine the thermodynamic parameters of binding metal ions with polynucleotides. Methods of research are the differential UV spectroscopy, thermal denaturation and spectroscopy of the visible range of wave numbers. The heteroatoms of nitrogen bases that coordinate the metal ions in polynucleotides were set and corresponding binding constants were calculated. Diagrams of the conformational equilibrium of polynucleotide metal complexes were obtained. Thermodynamic parameters of the ion binding to single- and multi-chain macromolecules were calculated, permitting to explain some peculiarities of phase diagram forms within “clips” theory frames. Conditioned with different types of ion interactions with DNA, constituents of changes in thermal stability of this polynucleotide were obtained. Sphere of use is the biotechnology, medicine, ecology, genetic engineering.