Energy landscape of an electron hole in hydrated DNA

First-principles/molecular mechanics, force-field, and 1-D lattice model schemes are used to address the energy landscape of an electron hole in hydrated DNA. Force-field calculations are used to derive a statistical description of the electrostatic fluctuations in DNA yielded by the polar environment, and a periodic first-principles/molecular mechanics scheme is employed to calculate the hole energy at uniform DNA segments embedded in hydrated DNA double helices. The results are then mapped onto 1-D lattice models to address issues relevant to charge transfer in hydrated DNA. It is shown that the polar environment generates an intense dynamical energy disorder along the DNA strands, exhibiting exponential spatio-temporal correlations. The fluctuations of the polar environment lead to hole states localized over a few DNA bases and compete evenly with the DNA sequence to define the hole energy landscape. The spatial correlations of the environment-induced fluctuations are also shown to influence strongly the hole transfer dynamics in DNA.