V2's effects on transitions to closed states outside of the main activation path. (*A*) WT (*dotted curves*) and V2 have nearly superimposable closed dwell-time histograms at very large depolarizations, indicating that the V2 has little effect on the transitions from *C* _{iN}, *C* _{f1}, and *C* _{f2} that correspond to each of the three components in these histograms. The time constants and amplitudes of the three exponentials fitted to 5 WT and 22 V2 closed time histograms at *V* ≥ +47 mV were averaged, and the curves reflect the derived means. (*B*) The measured open times for V2 at large depolarizations (▵) are approximately one-third as long as WT's (▪), indicating that V2 destabilizes the open state relative to *C* _{iN}, *C* _{f1}, and *C* _{f2}. Open times are uncorrected for missed events, but may be compared since WT and V2 display the same closed time distributions at these voltages (from *A*), and the analysis filtering bandwidths were set to be equal for WT and V2. Each value reflects a single experiment. (*C*) WT (*top*) and V2 (*bottom*) cumulative first latency histograms at +107 mV were fitted to the sum of two exponentials (see legend for Fig. *A*), starting at the time when *P* = 0.5. The dashed curves reflect the fast component in the same fits. The main difference between the fits for WT and V2 is the amplitude of the slow component with time constant τ_{s}, indicating that V2 increases the probability that a channel enters C_{i }states from closed states in the activation path. In the fitting, the values for τ_{s} for WT and V2 were 1.9 and 1.3 ms, respectively; values for the fast time constant τ_{a }were 0.21 and 0.29 ms. The values for *A*_{f} and *A*_{s} in the fits were adjusted for the delay in the fitted function. The two histograms reflect 182 and 258 sweeps, respectively. Patches w266 and v344.

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