Spin isomeric selectivity of water molecules upon DNA hydration

Four-photon coherent scattering of laser radiation was used to study the influence of DNA on the content of quasi-free ortho and para isomers of water molecules in its aqueous solution. It was shown that the concentration of quasi-free molecules that form the rotational spectrum of spin isomers increases considerably in the hydration shell of the DNA molecule as compared with pure water. The increase in the concentration of spin isomers occurs disproportionally. In the presence of DNA, the intensity of the rotational spectrum of ortho isomers is on the average much greater than that of para isomers. It was also demonstrated that the character of hydration and the ortho/para ratio change noticeably upon DNA denaturation, which may be evidence of changes in preferable solvation of DNA during its denaturation. The data obtained allowed us to assume that the stability of different biologically important states of macromolecules can be changed by varying the relative concentration of water spin isomers in solution.