Nonempirical Calculations of a Hydrated RNA Duplex

We have performed density functional theory based ab initio calculations on the crystal structure of sodium guanylyl-3‘-5‘-cytidine (GpC) nonahydrate. Our calculations are in good agreement with the experimentally determined X-ray structure. This is one of the first attempts to model ab initio nucleic acids in laboratory-realizable conditions. Comparison is also made with empirical force field based structure calculations.