Electron attachment dynamics to the guanine-cytosine (G-C) base pair in the gas phase is studied using DFT and molecular dynamics. The potential energy surface of the G-C anion is constructed with the empirical-valence-bond method using force-field information obtained from long-range corrected DFT calculations. Ring-polymer molecular dynamics simulations predict that the initial dipole-bound anion readily converts into the valence-bound anion within 0.1 ps and proton-transfer occurs subsequently within 10 ps. The same process was found in classical simulations, but on a much slower time scale. This result suggests that nuclear quantum effects are important in understanding DNA damage by low-energy electrons. (C) 2015 Elsevier B.V. All rights reserved.