FIGURE 4.

Effect of different gating swings. (A) The I-X curve became broader as δ increased from 2 to 10 nm. The operating ranges were 60 and 155 nm when δ = 2 and 10 nm, respectively. (B) As the gating swing increased, the F-X curve deviated more from the passive F-X curve. At F = 100 pN, the displacement was greater by 6 and 14 nm for δ = 2 and 10 nm, respectively, than for the passive displacement of 47 nm. (C) The activation profiles at F = 50 pN show that smaller δ activated more channels and had more channels remain open. (D) The bundle displacement responses at F = 50 pN show that because there was no fast adaptation there was no fast twitch when δ = 2 nm. On the contrary when δ = 10 nm, the twitch was as great as 17 nm (measured as the peak minus the displacement at t = 2.0 ms).