On the Long-Range Charge Transfer in DNA

The sequence dependence of charge transport through stacked Watson−Crick base pairs was analyzed for coherent hole motion interrupted by a temporary charge localization on guanine bases. The relative rate of hole transfer to the GGG sequence has been expressed in terms of the frequency of jumps through adenine−thymine base pairs separating adjacent guanine sites. The obtained expression yields practically the same sequence dependence as measurements, without invoking adjustable parameters. For alternating adenine−thymine/guanine−cytosine sequences, our analysis predicts that the relative charge-transfer rate varies in inverse proportion to the sequence length at short distances, with change to the slow exponential decay at longer distances.