Studies on tautomeric forms of Guanine-Cytosine base pairs of nucleic acids and their interactions with water molecules.
The relative stabilities of Guanine-Cytosine (G-C) DNA bare base pairs, its tautomeric forms and microhydrated base pairs are theoretically investigated with a focus on the keto-enol tautomerism as well as on the cis-trans isomerism using ab initio and density functional theory methods. The stabilities of the G-C bare base pairs, its tautomeric forms and microhydrated base pairs were affected by various factors including keto-enol tautomerization, cis-trans enol isomerization, and steric hindrance between the base pair and water molecules. The Atoms in Molecules theory (AIM) is employed to investigate H-bonding patterns both in bare and microhydrated base pairs. From the above topological results, an excellent linear correlation is shown between electron density [rho(r)], and its Laplacian [V2rho(r)] at the bond critical points. NBO analysis has been carried out to study the charge transfer between proton acceptor to the antibonding orbital of the X-H bond both in bare and microhydrated base pairs.
Deepa
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P
Department of Physics, Bharathiar University, Coimbatore-641 046, India.
Kolandaivel
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P
D020029:Base Pairing; D003596:Cytosine / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D007536:Isomerism; D008958:Models, Molecular; D014867:Water / Q000737:chemistry*
D014867:Water; D006147:Guanine; D003596:Cytosine