Monte Carlo simulation of hydration of the guanine-uracil pairs with guanine in two tautomeric forms: contribution of water bridging to relative stability of mispairs.

Results are presented from Monte Carlo simulation of hydration of guanine-uracil mispairs by 25 and 50 water molecules. The hydration shells of three mispairs formed between "normal" dioxo form of uracil (U) and three forms of guanine ("normal" amino-oxo tautomer G and two rotamers of the "rare" amino-hydroxy tautomer G*) depend on the tautomeric forms of the guanine molecule. The simulation shows the important role of hydration effects on the relative stability of the mispairs.