Site selective generation of guanine radical cation in duplex DNA: modulation of the direction of hole transport

Photoinduced electron transfer between cyanobenzophenone substituted 2′-deoxyuridine (dCNBPU) and GG sequence on the same strand of duplex DNA was examined. It was found that 5′-GTCNBPU-3′ was a most effective sequence for the generation of guanine radical cation, showing that DNA oligomers containing dCNBPU are widely usable for the studies for DNA-mediated charge transport. By using 5′-GTCNBPU-3′ sequence, we observed a remarkable one direction hole transport.