Interactions of hydrated Mg2+ cation with bases, base pairs, and nucleotides. Electron topology, natural bond orbital, electrostatic, and vibrationalstudy
J. Munoz et al., Interactions of hydrated Mg2+ cation with bases, base pairs, and nucleotides. Electron topology, natural bond orbital, electrostatic, and vibrationalstudy, J PHYS CH B, 105(25), 2001, pp. 6051-6060
A theoretical investigation of the influence of divalent metal cation bindi
ng on the nucleic base pairing is presented. The investigation includes a v
ariety of theoretical analyses, which include electron topology properties,
electrostatic properties, natural bond orbital analysis, and harmonic vibr
ational analysis. All calculations reported here involve pentahydrated Mg2 cation interacting with the base pairs GC, GG, and AU and their complexes
formed by the corresponding purine nucleotide. The present calculations pro
vide an important physicochemical insight into metal cation-base interactio
ns. Particularly, they allow us to explain the striking difference in the c
ation-induced enhancement of base pairing observed in G-containing base pai
rs compared to A-containing base pairs. Indeed, the results also reveal the
active role of hydrating water molecules in modulating the binding of the
cation through a specific network of hydrogen bonds with both the purine an
d the phosphate group. The results can be valuable for gaining further insi
ght into the effect of metal cation binding to the N7 site of guanine and a
denine in physiological DNA.