DFT investigation of the vibrational properties of AT base pairs in the presence of Ca2+ and Mn2+ ions

The binding effects of Mn2+ and Ca2+ ions on the vibrational properties of adenine-thymine (AT) base pairs have been investigated using density functional theory. The metallic atoms were coordinated to N3 and N7 atoms of adenine, respectively. We analyze the geometric properties of different metal-AT base pairs structures, as well as the vibrational bands that can be used to detect the presence of metallic ions. In particular we have found that strong vibrational amplitudes of metallic atoms are expected for the vibrational bands in the range between 400-500 cm(-1). Also, we point out the effects of cations binding over a series of selected modes, corresponding to experimental data, providing values for the resulting shifts for each of these vibrational bands.