The probabilities of inactive, intermediate, and active states were computed as above. This was repeated for 100 iterations, yielding a distribution of probabilities for each system. The mean values were used to report metastable populations, and the standard deviation of each distribution was used to report statistical uncertainties. Models where the conformational space is well sampled will show a smaller statistical uncertainty, as excluding a few trajectories should not significantly change the final probability values. The median and inter-quartile range (IQR) between quartiles 1 and 3 is reported to indicate the spread of the bootstrapped probabilities.