BINDING ENERGY DIFFERENTIATION OF WATER MOLECULES IN DNA HYDRATION SHELL

Анотація

An energetics study of water molecule binding to a DNA matrix has been performed. Bound water molecules have been differentiated according to their binding energies, the water molecules being supposed to participate in three types of sorption (hydration): sorption by Langmuir's binding centers , sorption by Henry's ones and multilayer sorption. It has been found that waters of the different sorption types take part in stabilizing a certain DNA conformation to a different degree. Consideration of the obtained values of free binding energies within each sorption type has shown that waters bound to Langmuir's centers mainly advantage A-DNA stabilization while ones bound to Henry's centers facilitate B-DNA stabilization. The water molecules bound in multilayer are more important for stabilization of both A- and B-form in comparison with unordered state, but largely for B-form. This is due to occurring the basic formation of multilayer part of hydration surroundings at high water content in DNA.