FIGURE 12.

Dependence on pulling force of enthalpy of activation for converting the open-to-closed complex, obtained from MD simulations determining work done by the enzyme on DNA segments. Data represented with lines are averages from Runs I and II; diamonds and squares represent separately Δh from Run I and Run II, respectively, with the error bars indicating standard deviations. For segments a, a′, and b′, at forces up to 20 pN, the dependence of the work on force is nearly linear, indicating the orientation of these segments is relatively insensitive to the force; however, segment b undergoes a marked reorientation near 10 pN that shifts the enthalpy of activation from negative to positive values.