Gain-of-function mutation in the KCNMB1 potassium channel subunit is associated with low prevalence of diastolic hypertension
J. Clin. Invest. José M. Fernández-Fernández, et al. 113:1032 doi:10.1172/JCI20347 [Go to this article.]

Figure 6
Fitting of the experimental data to an allosteric model of BK channel gating. (A and B) G-V plots for α+β_1WT (A) and α+β_1E65K (B) currents measured at 0 (circles), 100 nM (squares), 500 nM (triangles), and 10 μM (inverted triangles) Ca²⁺. Solid curves represent fits to Equation 1 (see Methods) with parameters restricted as described in the text. (C) G-V plots for α+β_1WT (solid line) and α+β_1E65K (dashed line) channels as predicted by the model. (D) V_1/2-versus-Ca²⁺ plots obtained from the G-V curves presented in C. (E) Allosteric kinetic scheme proposed for the BK channel by Horrigan and Aldrich (33, 34). The C-O transition corresponds to the closed-open equilibrium where L = L₀ exp(z_L × V / kT). The R-A transition corresponds to the resting-active equilibrium of a single voltage sensor where J = J₀ exp(z_J × V / kT). The X·Ca²⁺ transition is calcium binding to a single calcium sensor, with equilibrium constant K = [Ca²⁺] / K_d. These three equilibriums are related to each other by the allosteric factors C, D, and E, as shown. When there are n voltage sensors active, the C-O equilibrium constant is LDⁿ. Conversely, when the channel is open, the R-A equilibrium constant is JD. The same applies for the allosteric factors C and E.