Figure 12.

Forward-reverse-trapping activation model (Model FRT). (A) Gating scheme for GxTx-bound Kv2.1 trapping activation model. Four identical resting voltage sensors are independently trapped with trap rate k_tr and released with release rate k_re. Released voltage sensors activate with rate α and reverse rate β. Pore opening has forward rate k_open and reverse rate k_close. Rates susceptible to GxTx are red. (B) Simulated P_open from Model FRT with GxTx. Light pink, 60 mV; red, 90 mV; dark red, 120 mV. Dotted lines show fits of Eq. 3. τ_60mV = 21.296 ± 0.005 ms, σ_60mV = 3.851 ± 0.002; τ_90mV= 12.55 ± 0.01 ms, σ_90mV = 2.458 ± 0.005; τ_120mV = 8.07 ± 0.01 ms, σ_120mV = 1.941 ± 0.004. (C) Comparison of the reciprocals of rates k_re and k_tr to τ_ON from gating currents. Hollow circles, mean 1 µM GxTx Kv2.1 τ_ON from Fig. 8 E; filled circles, k_re⁻¹ from model; hollow triangles, k_tr⁻¹ from model. Solid lines show fits of Eq. 8, z_tr = 0.93 ± 0.17 e₀, k_{tr 0mV}⁻¹ = 26 ± 23 ms; z_rel = 1.0 ± 0.1 e₀, k_{re 0mV}⁻¹ = 115 ± 65 ms.