A brief derivation of this equation is also provided in Section 5. We perform an energy minimization for each APR window followed by 1 ns of equilibration and 30 ns of the production run. The free energy across the three phases was computed with the thermodynamic integration (TI) method, and blocking analysis was used to estimate the uncertainty in work done by each restraint in each window. The final SEM in ∆G b is obtained from bootstrap resampling (2000 iterations).