[Study of the interaction of DNA with manganese ions by IR-spectroscopy]

DNA complexed with Mn2+ ions in films is studied at different relative humidities and ion contents ([Mn2+]/[P] = 0.4-1) by IR spectroscopy. It is shown that substantially more sorbed water molecules are necessary for the transition of DNA complexed with Mn2+ ions into the double helical conformation (preferentially B-form) that for macromolecules in the absence of ions. DNA-Mn2+ complexes ([Mn2+]/[P] = 1) are able to absorb more water molecules than DNA. The results of the work evidence Mn2+ ion interaction with phosphates and nitrogen bases of the macromolecule: N7G, O6G.