Figure 4.

Dependence of 2D association kinetics on the BFP spring constant. (A) The bond waiting time distributions under indicated BFP spring constant κ and matched by our model. (B) Apparent 2D on-rates $\langle A_{\text{c}}\rangle k_{\text{on}}^{\text{m}}$ were plotted versus κ. The adjustment in κ was achieved by varying the aspiration pressure in the micropipette. (C) Plots of the average waiting time 〈t_w〉 versus κ. (D) Plots of the average bond lifetimes 〈t_b〉 versus force, κ corresponding to each force are indicated. The error bars represent SEM. All the data of experiments (symbols) and models (curves) were obtained at constant gap distances (d = 50, 78 nm).