The reduction potential of the slipped GC base pair in one-electron oxidized duplex DNA

Redox equilibrium between the low potential aniline cation radical and the guanyl radical in the GC base pair of duplex DNA has been established using pulse radiolysis. We relate the finding of a radical one-electron reduction potential, E0’, of 1.01 ± 0.03 V to the perturbation of the GC base pair to accommodate the neutral guanyl radical in an energetically more stable ‘slipped’ structure. The proposed radical pathway is supported by DFT calculations.