A theoretical exploration of the photoinduced reductive repair mechanisms of thymidine glycol

•The reductive repair mechanisms of dTg via electron transfer were explored at the theoretical level.•dT is the most feasible reductive product of dTg.•dT is also the feasible degradation product of 5-HOdT.•This work helps shed light on the interaction between low-energy electron and DNA base.

The potential energy surface for the reductive repair of thymidine glycol (dTg) via electron transfer in aqueous solution has been mapped out in the present study employing a hybrid function of BH&HLYP in conjunction with the 6-311+G(d,p) basis set. Two types of repair mechanisms have been explored, including the reductive modification of the base portion and the excision of the base. The results indicate that thymidine (dT) is the most energetically feasible reductive product of dTg and also is the feasible degradation product of 5-hydroxy-5,6-dihydrothymidin-6-yl radical. The latter, however, has not been characterized in the previous experimental investigation. The insights explored in this paper help shed light on the interaction between low-energy electron and DNA base.

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