Computational modeling of charge transfer in DNA

Abstract

During the past decade, charge transfer (CT) through DNA has been an area of extensive experimental and theoretical studies. The migration of excess charge plays an important role in DNA damage and repair and it is of great potential for molecular electronics. The CT process mediated by DNA is essentially determined by the structural dynamics of the π stack and its surroundings. Theoretical calculations provide microscopic insights into CT characteristics which are difficult to analyze by experimental techniques, and therefore, they are essential for understanding how and why charge transport occurs. In this chapter we deal with various aspects of computational modeling of CT in DNA. We consider estimation of key parameters-the driving force δG°, the electronic coupling Vda and the reorganization energy λ, that govern CT efficiency in DNA. The effects of molecular motions on these quantities are described. We discuss excess charge delocalization over adjacent base pairs. The mechanistic details derived from theoretical calculations are used to analyze the consistency and limitations of mechanisms for CT. In the last section, we consider some perspectives of theoretical studies on charge movement in DNA based systems and formulate some requirements to computational tools for microscopic modeling of the electron transfer process. © 2006 Springer.