Fig. 6. Mechanical unfolding of C1_CP-df. C1_CP-df was constructed in the same way as C1_CP except that the ester bond was replaced by a disulfide bond.

a Three possible unfolding/hydrolysis pathways of C1_CP-df under load and the corresponding contour length change. b Representative force–extension curves of the “Disulfide unformed” group. c Representative force–extension curves of the “Disulfide unruptured” group. Representative force–extension curves of the “Disulfide ruptured” group in PBS with (d) and without (e) 10 mM TCEP. f Histogram of the mechanical rupture force of disulfide bond in PBS with 10 mM TCEP. Fitting the force distribution with Monte Carlo simulation results in a Δx_u of 0.13 nm and ₀ of 0.39 s⁻¹ (Supplementary Fig. 18). g 2D bars show the relative populations of the three kinds of events without (left, n = 844) or with 10 mM TCEP (right, n = 754). This experiment was repeated more than five times independently with similar results. Source data are provided as a Source Data file.