Kinetic model of gating at the selectivity filter. (A) Voltage dependence of relative areas of fast and long closed states. Three distinct regions characterized by different voltage dependence are depicted in different shades of gray. (B) Voltage dependence of mean open times, corrected for missed events. Three distinct regions of behavior at these different voltages are highlighted in shades of gray. (C) A kinetic scheme of the TREK-2 selectivity filter gate with three sets of open (O), short (C_F), and long closed states (C_S) affecting three distinct voltage regions depicted in A and B. (D–G) Voltage dependence of intrinsic mean open time (D), short closed time (E), long closed time (F), and relative areas of short and long closed times (G). The lines are a fit of the kinetic model in C to the data shown in Fig. 5 with the following parameters: A₁₂ = 5 ms⁻¹, A₂₁ = 20 ms⁻¹, α₁₂ = 0.46, α₂₁ = −0.46, A₂₃ = 21 ms⁻¹, α₂₃ = 0.95, A₃₂ = 3.5 ms⁻¹, α₃₂ = −0.95, B₂ = 4.2 ms⁻¹, β₂ = 1.3, B₋₂ = 7.2 ms⁻¹, β₋₂ = 1.6 × 10⁻⁵, B₃ = 6.2 × 10⁻³ ms⁻¹, β₃ = 1.1, B₋₃ = 7.5, β₋₃= 2.1 × 10⁻⁵, D₂ = 2.4, δ₂ =1.2 × 10⁻⁵, D₋₂ = 1.6, δ_-2=−0.17, D₃ = 1.7 ms⁻¹, δ₃ = 6.4 × 10⁻⁵, D₋₃ = 4 ms⁻¹, δ₋₃ = −0.30.