Various binding sites in DNA bases and base pairs as predicted by rigorous analysis of the molecular electrostatic potential (MESP) are explored for coordination with Li+ and Ca2+ cations; the electrostatics is generally seen to provide an explanation for the observed trends in binding upon subjecting the anticipated structures to optimization at a high level ab initio theory.
Gadre, S. R., Pundlik, S. S., Limaye, A. C., & Rendell, A. (1998). Electrostatic investigation of metal cation binding to DNA bases and base pairs. Chemical Communications, 573-574. https://doi.org/10.1039/A708372F