| Abstract
| - A theoretical investigation of the influence of divalent metal cation binding on the nucleic base pairing ispresented. The investigation includes a variety of theoretical analyses, which include electron topologyproperties, electrostatic properties, natural bond orbital analysis, and harmonic vibrational analysis. Allcalculations reported here involve pentahydrated Mg2+ cation interacting with the base pairs GC, GG, andAU and their complexes formed by the corresponding purine nucleotide. The present calculations provide animportant physicochemical insight into metal cation−base interactions. Particularly, they allow us to explainthe striking difference in the cation-induced enhancement of base pairing observed in G-containing basepairs compared to A-containing base pairs. Indeed, the results also reveal the active role of hydrating watermolecules in modulating the binding of the cation through a specific network of hydrogen bonds with boththe purine and the phosphate group. The results can be valuable for gaining further insight into the effect ofmetal cation binding to the N7 site of guanine and adenine in physiological DNA.
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