Reactivities of radicals of adenine and guanine towards reactive oxygen species and reactive nitrogen oxide species: OH and NO2

Reactions of radicals of the DNA bases with reactive oxygen species and reactive nitrogen oxide species produce mutagenic products. We have studied reactivities of all the carbon sites of radicals of adenine A(-H) and guanine G(-H) obtained by removal of H-atoms from their nitrogen sites towards OH and NO2. We studied stabilities of A(-H) and G(-H) and binding energies of their adducts with each of OH and NO2 using density functional theoretic and MP2 calculations employing the AUG-cc-pVDZ basis set. Solvation in aqueous media was treated using the polarization continuum model. The results obtained explain experimental observations.