Theoretical study of hydrogen peroxide interacting with DNA base and DNA base pair in terms of ab initio method and ABEEMσπ/MM fluctuating charge potential model

The optimized geometries, interaction energies, dipole moments, and vibrational frequencies of guanine-hydrogen peroxide (GHP), cytosine-hydrogen peroxide (CHP), adenine-hydrogen peroxide (AHP), thymine-hydrogen peroxide (THP), guanine-cytosine-hydrogen peroxide (GC-(HP)n(n = 1-2)), and adenine-thymine-hydrogen peroxide (AT-(HP)n(n = 1-2)) complexes are investigated by ab initio methods and ABEEMσπ/MM fluctuating charge potential model. All geometries of guanine-cytosine-hydrogen peroxide (G-C-HP) and adenine-thymine-hydrogen peroxide (A-T-HP) complexes were obtained using B3LYP/6-311++G(d,p) method, and the energies were determined at the MP2/6-311++G(2d,2p) level with BSSE corrections. The ABEEMσπ/MM model gives reasonable geometries and interaction energies compared with the present ab initio methods. For G-C-HP and A-T-HP clusters, the linear coefficient of the interaction energies all reaches 0.998, and the average absolute deviation (AAD) are 0.95 and 1.42 kcal/mol, respectively, when compared with MP2/6-311++G(2d,2p)‖B3LYP/6-311++G(d,p) method. Moreover, the variations of hydrogen bond length of guanine-cytosine and adenine-thymine base pair affected by hydrogen peroxide molecules computed by ABEEMσπ/MM model are all obtained reasonable accordance with B3LYP results. The current study will avail to understanding the physiological relevance in DNA damage.