The temperature dependence of the Gibbs free energy, ΔG, of the equilibrium between the hairpin and duplex forms of the 16-mer, parameterized by Mg2 + concentration from 0.1 to 3 molar equivalents. For the sake of clarity, the experimental points are only displayed for 0 (gray), 0.1 (blue), and 3 (red) molar equivalents of Mg2 + . A color gradient from orange to mauve symbolizes displacement of the equilibrium between the hairpin (mauve) and the duplex form (orange) of the 16-mer