Theoretical investigation of the hydrogen atom transfer in the hydrated A-T base pair

The hydrated A-T base pair has been studied in order to understand the structural modifications and their electronic rearrangements induced by the movement of the hydrogen atoms in the H-bonds. The comparison of these results with that of the nonhydrated system can explain the role of the H-bonds of the water molecules in this system. Two naive schemes have been considered, one where the hydrogen bonds of the water molecules are only indirectly involved in the hydrogen atoms transfer between the bases and another where the water molecules are directly involved in this transfer. The results support the idea that the real mechanisms are more complexes than these schemes. Some new stable structures of the A-T(H2O)(2) and the A-T(H2O)(4) systems have been found and the mechanisms of their generations have been analysed. (C) 2011 Elsevier B.V. All rights reserved.