FIGURE 4.

Influence of the shape of triangular binding potentials for two bonds in series. The two binding potentials of the reference (blue) and the sample (red) bond are plotted on left. The differences in potential width and depth are magnified in the inserts. The resulting survival probabilities of the two bonds are plotted on the right side. The loading rates are r₀ = 0 pN/s, r₁ = 4 × 10⁻⁹ pN/s, r₂ = 1.5 × 10⁻⁴ pN/s, r₃ = 4 pN/s, and r₄ = 1 × 10⁵ pN/s. The applied forces are f₀ = 0 pN, f₁ = 10 × f_R, f₂ = 20 × f_R, f₃ = 30 × f_R, and f₄ = 40 × f_R with f_R = k_BT/Δx_R = 1.48 pN. (A) Perfectly symmetric molecular balance with identical potential width Δx_R,S = 2.8 nm and natural dissociation rates k_R0,S0 = 2.82 × 10⁻¹⁴ s⁻¹ . Black circles indicate the survival probability for the sample bond (red curves) for a given loading rate r_0,1,2,3,4 and rupture force f_0,1,2,3,4. (B) Asymmetry in potential depth, which corresponds to an asymmetry in k_R0,S0 for a molecular balance with identical Δx_R,S but different k_S0 = 8.46 × 10⁻¹⁴ s⁻¹. The survival probability of the sample bonds indicated by the black circles is the same for different loading rates r_0,1,2,3,4 and rupture forces f_0,1,2,3,4. (C) Asymmetry in Δx_R,S with identical k_R0,S0 but different Δx_S = 2.66 nm. The survival probability of the sample bonds, indicated by the black circles, rises with higher loading rates and rupture forces. (D) Mixed asymmetry with differences in k_R0,S0 (k_R0 = 2.82 × 10⁻¹⁴ s⁻¹, k_S0 = 8.46 × 10⁻¹⁴ s⁻¹) and Δx_R,S (Δx_R = 2.8 nm, Δx_S = 2.66 nm). The sample bonds (red curve) have a lower survival probability than the reference bonds (blue curve) for low loading rates but rises with higher loading rates and rupture forces. The crossover occurs at a rate of r_c = 9 × 10⁻⁴ pN/s.