Understanding hydrogenation of the adenine‐thymine base pairs and their anions: A density functional study

Abstract

The B3LYP/DZPþþ approach has been used to investigate the properties of hydrogenated radicals and anions of adenine-thymine (A-T) base pairs. Our calculations show that the hydrogenated radicals and anions have relatively high stabilities compared with the single adenine and thymine base. The conformations and hydrogen-bond interactions of A-T base pairs have obviously changed once the hydrogen atoms attached to the A-T base pairs and their anion. As for the hydrogenated A-T radicals, all of them exhibit relatively high electron affinities and different hydrogenation properties with respect to their components. The process of the bond formations of (C6)-H (adenine) and (C6)-H (thymine) are the most favorable in energetics. The two hydrogenation channels have the reaction Gibbs free energies (DG ) of À51.8 and À54.2 kcal mol À1 , respectively. Also, the calculations on the basis of CPCM model imply that the solvent effect plays an important role in the electron attachment and hydrogenation reactions, and can stabilize the hydrogenated A-T anions.

DFT study on addition reaction mechanism of guanine-cytosine base pair with OH radical

“…[93][94][95][96][97] This method has predicted the reasonable results for nucleic components systems. [62,[97][98][99][100][101][102][103][104][105][106] Local minima and transition states were identified by imaginary frequencies.…”

“…Geometry optimizations and frequency calculations were carried out using the B3LYP hybrid density functional with the double‐ζ quality basis sets with polarization and diffuse functions (DZP++) . This method has predicted the reasonable results for nucleic components systems . Local minima and transition states were identified by imaginary frequencies.…”