Recently there has been great interest in the conducting properties of DNA because of their potential applications to nanotechnology and their role in protecting the molecule from oxidative damage. Unfortunately, experiments have provided very contradictory results. Using state of the art ab-initio simulation we investigated the hole localization and transfer in both a laboratory realizable polydGpCp wet Z-DNA molecule and in a fully solvated B-DNA Key words: Density functional calculations; DNA damage; electron transfer; molecular dynamics; nucleobases