FIGURE 4.

Force traces for P5ab hairpin with 3.2 Kbp handles in PM from the simulations for two different trap stiffnesses ɛ_b ≈ 0.1 pN/nm (upper panel) and ɛ_b ≈ 0.035 pN/nm (lower panel). The bandwidth used is 1 KHz. We show the mean forces, f^F and f^U, in the upper and lower parts of the square-like-sign force traces, corresponding to the forces at the folded and unfolded states, respectively. Note that the value of such forces, f^F and f^U, is higher than the ones measured in experiments (1) by ∼1–1.5 pN. This discrepancy is consistent with the fact that the free energy parameters for P5ab used in simulations (32–34) corresponds to higher salt concentrations than the experimental ones.