Table S1.

Fitting parameters for unfolding rates of SH3 domain as a function of force for WT and V61A mutant from simulations and experiment

Name	$k_L^0$	$k_H^0$	$x_L$	$x_H$	$k^0$	x	$P_2/P_1$
Simulation WT	1.47	$3.88\cdot {10}^{-3}$	0.40	1.16	0.76	0.58	${10}^3$
Simulation V61A	2.45	$4.20\cdot {10}^{-1}$	0.02	0.67	1.29	0.52	${10}^5$
Experiment WT	$2.15\cdot {10}^{-2}$	$6.31\cdot {10}^{-6}$	0.07	1.42	$9.59\cdot {10}^{-4}$	0.82	${10}^{17}$
Experiment V61A	$3.83\cdot {10}^{-2}$	$8.46\cdot {10}^{-4}$	0.0	1.15	$3.50\cdot {10}^{-3}$	0.94	${10}^5$
Units	Seconds−1	Seconds−1	Nanometers	Nanometers	Seconds−1	Nanometers	1

Two types of fits were made: exponential fits $k_u=k^0\exp \left(fx/k_{B}T\right)$ and double-exponential fits $k_u=k_L^0\exp \left(f{x}_L/k_{B}T\right)+k_H^0\exp \left(f{x}_H/k_{B}T\right)$. $P_2/P_1$ shows the relative likelihood of the double-exponential model with respect to the single-exponential model, as assessed by Akaike information criterion.