DFT study on the attacking mechanisms of H and OH radicals to G-C and A-T base pairs in water

Abstract

Improvement of cross-tension strength using concave electrode in resistance spot welding of high-strength steel sheets AIP Conference Proceedings 1709, 020003 (2016) Abstract.To elucidate the effect of radicals on DNA base pairs, we investigated the attacking mechanism of OH and H radicals to the G-C and A-T base pairs, using the density functional theory (DFT) calculations in water approximated by the continuum solvation model. The DFT calculations revealed that the OH radical abstracts the hydrogen atom of a NH 2 group of G or A base and induces a tautomeric reaction for an A-T base pair more significantly than for a G-C base pair. On the other hand, the H radical prefers to bind to the Cytosine NH 2 group of G-C base pair and induce a tautomeric reaction from G-C to G*-C*, whose activation free energy is considerably small (-0.1 kcal/mol) in comparison with that (42.9 kcal/mol) for the reaction of an A-T base pair. Accordingly, our DFT calculations elucidated that OH and H radicals have a significant effect on A-T and G-C base pairs, respectively. This finding will be useful for predicting the effect of radiation on the genetic information recorded in the base sequences of DNA duplexes.

Local μ-Opioid Receptor Antagonism Blunts Evoked Phasic Dopamine Release in the Nucleus Accumbens of Rats

“…24 These results raise the hypothesis that endogenous opioids in the NAc promote reward-seeking behavior by increasing the release of dopamine from dopamine terminals. Consistent with this idea, NAc MOR activation can increase dopamine levels in the NAc as measured by microdialysis, [25][26][27][28][29] perhaps by inhibition of GABA release onto cholinergic neurons that stimulate dopamine release via nicotinic receptor-mediated excitation of dopamine terminals. [30][31][32] Although much evidence suggests that activation of MORs within the NAc is sufficient to enhance tonic dopamine, it is presently unclear whether endogenous opioids promote phasic dopamine release.…”

A TD-DFT-Based Study on the Attack of the OH· Radical on a Guanine Nucleotide

“…Sadr et al [ 11 , 12 , 13 , 14 ] have used the DFT to study the fragmentation of cytosine, adenine, guanine, and uracil bases. Okutsu et al [ 15 , 16 ] investigated the attacking mechanisms of radicals to base pairs in water, and Santosh and Abolfath [ 17 ], the relation of the molecule charge with the bond dissociation and fragmentation behavior of DNA bases. However, no time-dependent calculation was carried out by these authors, nor did they study the dynamics of the collision.…”