The Role of Hole Traps in DNA

Abstract

Two types of whole trap have been discussed for DNA. One type was introduced by Reynaud et al. (Jour. Am. Chem. Soc. 2013, 135, 3953) to account for the properties of whole conduction in an adeninethymine (AT) DNA. In their treatment there is associated with each adenine a conducting state Ai and a trap state ti. These states are assumed to survive unchanged as the hole moves along the chain, leaving partial hole populations on Ai and ti . We point out that traps such as ti cannot exist on DNA. A second type of trap, found in simulations for a hole introduced into AT DNA, is due to the polarization of the surrounding water by the hole when it is localized on an adenine, thus a kind of selftrapping. Currently the weight of experimental data strongly favors hopping as the transport mechanism, but the details of the hopping process are not entirely clear. We suggest that the self-trapping, plus some assistance by positive ions to exit the traps, can account for whole conduction