(color online) The PRE to POST movement of Tyr639 and the outward rotation of the O helix and fingers domain are weakly dependent upon each other. (a) The time series of the change in position of Tyr639 relative to the PRE position (red line) and that of Arg627 relative to the position when the O helix and fingers domain are in the closed conformation (blue line) in system 5, in which a constant force of 100 pN is applied to the C-terminus of the Y helix to facilitate the outward rotation of the fingers domain in system 3. The latter trace is offset by −0.2 nm on the y axis for clarity. (b) A snapshot of the structure obtained from the trajectory shown in panel (a), where Tyr639 is in the POST position and the O helix and fingers domain are in the open conformation (yellow). The structures of the enzyme shown in red and green are the same as those in Fig. 2(b). (c) The change in position of Arg627 over time relative to the position when the O helix and fingers domain are in the closed conformation (blue line) for system 6 where Tyr639 is restrained in system 3. (d) A snapshot of the structure obtained from the trajectory shown in panel (c), where Tyr639 is in the POST position and the O helix and fingers domain are in the semi-closed conformation (yellow). The structures of the enzyme shown in red and green are the same as those in Fig. 2(b). (e) The position distribution of Arg627 for system 6 with 20 trajectories with a simulation period of 10 ns. The blue line represents the Gaussian fit.