Original Articles
Neha Shukla, Brijesh Kumar Sha
Abstract
Uracil is a naturally occurring pyrimidine derivative and is one of the four nitrogenous bases found in RNA. Hydrogen bond plays a significant role in the structure determination of nucleic acids. Various types of hydrogen bond formed by purine and pyrimidine bases have been investigated and are of great significance. The effect of hydrogen bond on various Uracil-Water complexes has been investigated. In this paper four cyclic isomers of uracil forming hydrogen bonds with the water molecule have been discussed. Optimized geometries of all the isomers of uracil-water complex have been obtained at MP2/6-311++G (d,p), B3LYP/6-311++G (d,p), B3LYP/Aug-CC-pVDZ levels for the first time upto this level. Structural parameters of the optimized geometries, total energies and the APT charges of uracil-water complex have been computed. We show that addition of water molecules in uracil, the strength of the binding energy decreases i.e. stability increases. The optimized bond length and bond angles are in agreement with the corresponding experimental results.