IR-spectroscopy of DNA water solutions in the presence of metal ions

Abstract

DNA solutions in the presence of Ca2+, Mn2+ and Cu2+ ions were studied using FTIRspectroscopy and DNA melting analysis. An approach to the analysis of the IR-spectra of DNA was proposed. The approach is based on decomposition of complex bands in the region of carbonyl vibrations. It was shown that ions can interact with nitrogenous bases. It was also shown that the interaction of Ca2+ and Mn2+ ions occurs via water molecules, while Cu2+ ions bind the bases directly. The significant influence of Ca2+, Mn2+ and Cu2+ ions on the conformational stability of the DNA double helix has been demonstrated. It was shown that Ca2+ and Mn2+ ions stabilize the DNA structure while Cu2+ ions serve to reduce its thermodynamic stability. Refs 23. Figs 4. Tables 1.