The transition rates and parameter values used in our description.

Although the values of most parameters have been measured or can be estimated in the force-free case, the values describing the force dependence have been determined by fitting our model to the experimental data. Note that the transition rate for ATP release is determined by the balance condition of Eq 43 and is not a free parameter of the description. Because the reported values have been measured at room temperature, we use kBT = 4 zJ. Rate constants with a superscribed zero indicate the value in the absence of an external force. The carets denote second-order rate constants with units of s−1M−1.