Figure 5. Kinetics of dye-binding for mono- (open symbols) and bis-intercalators (closed symbols).

(a) Comparison of measured k_off values (black circles) with the corresponding equilibration rate k_eq (blue diamonds) for 10 nM SbG at 1,000 mM NaCl reveals that the difference between k_eq and k_off scales with the dye coverage (cf. equation (6), Methods) such that significant deviations are only observed at high tension. A direct calculation of k_off based on the measured and k_eq and equation (6) (blue diamonds) shows that the measured and calculated k_off are in good agreement. (b–h) Measured (inverse) off- (black circles) and on-rates (red squares). SbG with 100 mM NaCl (b); SxO with 100 mM NaCl (c) and 1,000 mM NaCl (d); YO (e) and SxG (f) with 100 mM NaCl; POPO with 100 mM NaCl (g) and 1,000 mM NaCl (h). Grey curves show exponential fits of the data. The fits in h are restricted to the force range 0<F≤24 pN because k_off(F) exhibited a nonexponential force dependence at higher forces. Error bars, s.e.m., n≥5.