Experimental and computational approach to the rational monitoring of hydrogen-bonding interaction of 2-Imidazolidinethione with DNA and guanine.

The hydrogen-bonding interaction of 2-Imidazolidinethione with DNA and guanine has been investigated using UV/vis, circular dichroism, differential pulse voltammetry and ab initio chemical mechanic quantum procedures. The bonding constant of 2-Imidazolidinethione with DNA was measured by UV/vis spectroscopy and is estimated to be 1.4x10(3). In order to prove of hydrogen-bonding formation, the bonding constants of 2-Imidazolidinethione with guanine in Tris-HCl buffer and binary mixture of buffer-acetonitrile were measured. In addition, density functional theory calculations, using ab initio methodology at the 6-31+G(d,p) level and simulating the effect of solvents on interaction by mean of the Cosmo Polarizable Continuum Model (CPCM), were performed on the single and complex of 2-Imidazolidinethione and guanine molecules. However, we concluded that 2-Imidazolidinethione interacted with N(3) of guanine in minor groove of DNA.