Proton Tunneling in Radiation-Induced Mutation

The equilibrium proton distribution and tunneling rate in the N-H. . . N hydrogen bond of the guanine-cytosine base pair have been calculated quantum mechanically for the ground state, a charge-transfer excited state, and positive and negative ionic states. These results are consistent with the idea that tautomeric rearrangement can be a cause of radiation induced mutation or carcinogenesis.