Electrostatic potential values at cation locations in the DNA major groove.

Poisson-Boltzmann electrostatic potentials (Ep) were calculated for 0.5 Å sided cubes centered on the average position of Mg2+ observed in MD structures (Figure 1). These squares were shifted along the five Ni–1piNi dinucleotide steps composing the T20p21C21p22A22p23G23p24A24p25A25 fragment. The potentials are sorted according to the conformational state of pi–1. A total of 100 snapshots extracted from S1 were examined. Standard deviations are given in parentheses.