BASE SEQUENCE EFFECTS ON CHARGE CARRIER GENERATION IN DNA:: A THEORETICAL STUDY.

We have thoroughly analyzed the electronic structure of stacked DNA Watson–Crick (WC) base pair dimers using ab initio Hartree–Fock and semiempirical Hartree–Fock-configuration-interaction quantum chemistry. We consider all the possible base compositions and sequences at the nucleoside level in vacuo. The results show that in such systems charge carrier generation could in principle be possible via charge transfer excitons, which turn out to dominate the first excited electronic states of the WC base pairs and their stacked dimers, and this process is largely sequence- and conformation-dependent. Possible consequences of this result for polymeric DNA duplexes are discussed. [ABSTRACT FROM AUTHOR]