Figure 4.

Results for squid optic lobe kinesin at saturating ATP. Lines denote theoretical results, and symbols denote experimental data from Schnitzer et al.³³ (adapted with permission from Springer Nature). (a) Velocity vs external force. The black solid line denotes the theoretical results calculated with more precise eq 7, and the green dashed line denotes the theoretical results calculated with simpler eq 10. Since the green dashed line is almost coincident with the black solid line, the two lines are almost indistinguishable. (b) Stepping ratio vs external force. The black solid line denotes the theoretical results calculated with more precise eq 5, and the green dashed line denotes the theoretical results calculated with simpler eq 8. (c) Run length vs external force. The dashed blue line denotes the theoretical results calculated by considering that the motor can only dissociate in the weak MT-binding state, and the black solid line denotes the theoretical results calculated by considering that the motor can dissociate in both the weak and strong MT-binding states with ε_s0 = 0.1 s^–1. Since the dashed blue line is almost coincident with the black solid line at F < −2 pN, the two lines at F < −2 pN are almost indistinguishable. (d) Dissociation rate vs external force. The dashed blue line denotes the theoretical results calculated by considering that the motor can only dissociate in the weak MT-binding state, and the black solid line denotes the theoretical results calculated by considering that the motor can dissociate in both the weak and strong MT-binding states with ε_s0 = 0.1 s^–1.