DFT AND MP2 INVESTIGATIONS ON THE HYDROGEN BONDING INTERACTION BETWEEN 5,6-DIHYDROTHYMINE AND DNA BASES: A, C, G, T
Z.M. Qiu1, H.Z. Cai1, H.L. Wang1, Y.M. Xia2, H.J. Wang2
1Henan Quality Polytechnic, Pingdingshan, China
qiuzaiming@hotmail.com
2State Key Laboratory of Food Science and Technology, Jiangnan University, China
Keywords: DNA bases, hydrogen bond, 5,6-dihydrothymine
Abstract
5,6-Dihydrothymine (DHT) is a nucleobase lesion induced by the action of ionizing radiation on thymine residue in DNA. In this work, we present the hydrogen bonding base pairs involving 5,6-dihydrothymine bound to four bases in DNA: adenine (A), cytosine (C), guanine (G), and thymine (T). Full geometry optimizations are performed for the studied complexes by the B3LYP method. Interaction energies are corrected for the basis set superposition error, using the full Boys-Bernardi counterpoise correction scheme. Hydrogen bonding patterns of these base pairs are characterized using NBO and AIM analysis. According to the calculated binding energies and structural parameters, the stability of the base pairs decrease in the following order: DHT:G ~ DHT:A > DHT:C > DHT:T.
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