Figure 4. Base selectivity of cation-pi and coupled hydrogen bonding interactions.

a) The number of cation-pi interactions in major (blue bar) or minor (green bar) groove is given for each of the four bases. b) The number of each base type adjacent to the base involved in cation-pi interaction(s) that also hydrogen bond or form ion/dipole interactions (1jgr) with the cation/FSW. The hydrogen bonding base is positioned 3’ for major (blue bar) and 5’ for minor groove (green bar) cation-pi interactions.