Figure 7.

Kinetic analysis of experiments at varying [Mg²⁺]. (A) Experimental distribution of the unfolding rupture forces in buffers containing 0.00 mM (red), 0.01 mM (green), 0.1 mM (blue), 0.5 mM (magenta), 1 mM (cyan), 4 mM (orange) and 10 mM (black) of [Mg²⁺] and 50 mM of monovalent cations. These experiments were done at a loading rate of 1.8 pN/s. (B) Average rupture forces 〈f_U(F)〉 and standard deviations σ_U(F) obtained in experiments done at different [Mg²⁺] and at loading rates of 1.8 pN/s (red) and 12.5 pN/s (blue). Filled symbols refer to unfolding and empty symbols to folding. (C) Log-linear plot of the transition rates versus force. Experiments were done at 0.00 mM [Mg²⁺] for loading rates of 1.8 pN/s (dark red) and 12.5 pN/s (red), at 0.01 mM [Mg²⁺] for loading rates of 1.8 pN/s (dark green) and 12.5 pN/s (green), at 0.1 mM [Mg²⁺] for loading rates of 1.8 pN/s (dark blue) and 12.5 pN/s (blue), at 0.5 mM [Mg²⁺] for loading rates of 1.8 pN/s (dark violet) and 12.5 pN/s (magenta), at 1 mM [Mg²⁺] for loading rates of 1.8 pN/s (dark cyan) and 12.5 pN/s (cyan), at 4 mM [Mg²⁺] for loading rates of 1.8 pN/s (dark orange) and 12.5 pN/s (orange), and at 10 mM [Mg²⁺] for loading rates of 1.8 pN/s (gray) and 12.5 pN/s (black). (D) Dependence of the effective barrier B_eff(f) on force at different [Mg²⁺]. Color code as in (C).