[Conformation of a DNA molecule in water-salt solutions depends on the salt anion type].

The methods of viscosimetry and flow birefringence were used to study the effect of anions F-, Cl-, Br-, J-, NO3-, ClO4-, SCN-, CH3COO- on the dimensions and thermodynamic rigidity of the DNA molecule in solutions in a wide range of ionic strengths and at different temperatures. It was shown that the persistent lengtH of DNA is independent of the anion type at all values of ionic strength, and the changes in its dimensions, which are determined from the changes in intrinsic viscosity, are due to the influence of anions and their hydration on long-range interactions in the macromolecule. Possible reasons for this phenomena and the role of structural changes in water upon hydration of anions are discussed.