PNNL

Abstract

The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. It is believed that guanine, a basic component of DNA and RNA, has the smallest affinity to an excess electron among all nucleic acid bases. Our experimental and computational findings indicate, however, that many so far neglected tautomers of guanine support adiabatically bound anionic states in the gas phase. The computed values of electron vertical detachment energy for the most stable anionic tautomers are within a broad range of the dominant feature of the photoelectron spectrum. We suggest that guanine might be the strongest excess electron acceptor among nucleic acid bases. Thus it might be critical to radiobiological damage of DNA and it might contribute to those chemical transformations of DNA that proceed through bound anionic states.