Figure 2: Single-molecule force-induced rupture and force spectrum.
From: Deciphering the scaling of single-molecule interactions using Jarzynski’s equality
(a) Typical non-equilibrium single-molecule rupture event measured in 1 mM NaCl, pH 6.5 at a pulling speed vp=0.25 μm s−1. The approach and retract curves are indicated. The AFM zero distance, the distance to bond breaking DB as well as the contour length, Lc (16.43 nm) of the used PEG tethers are indicated. Inset: About 100 pulling trajectories aligned with respect to pulling time using the best WLC-fit (red line, with persistence length as 3.65 Å). The scale bars are 2 nm and 5 ms. (b) Dynamic force spectra showing the logarithmic loading rate (LR=vpk) dependency of the unbinding force at pH=6.5. The near-equilibrium unbinding is visualized as a plateau for loading rates <105 pN s−1. Non-equilibrium binding regimes are fit to the Bell–Evan’s equation as indicated by the solid line. The error bars represent s.e.m. Inset: histogram of breaking forces fitted to a Gaussian to extract the most probable unbinding force, F*.
