Table 2. Energetic parameters for the BK... | Rockefeller University Press

Table 2.

Energetic parameters for the BK channel gating model

Energetic parameter	Value
V_M (x = 0)^a	138.6 mV
V_M (x → ∞)^a	30.7 mV
x_m (V → −∞)^b	14.7 µM
x_m (V → ∞)^b	0.83 µM
$Q_{\max} F V_{M} \|_{x = 0} + R T N_{\max} \ln x_{m} \|_{V \to ∞}$ ^c	−24.1 kcal/mol
$Q_{\max} F V_{M} \|_{x \to ∞} + R T N_{\max} \ln x_{m} \|_{V \to - ∞}$ ^d	−23.9 kcal/mol
ΔG_model^e	−24.6 kcal/mol
$Q_{\max} F Δ V_{M}$ ^f	−6.7 kcal/mol
$- R T N_{\max} \ln (\frac{x_{m} \|_{V \to ∞}}{x_{m} \|_{V \to - ∞}})$ ^g	−6.5 kcal/mol
$Δ G_{int}$ (model)^h	−6.8 kcal/mol

Energetic parameter	Value
V_M (x = 0)^a	138.6 mV
V_M (x → ∞)^a	30.7 mV
x_m (V → −∞)^b	14.7 µM
x_m (V → ∞)^b	0.83 µM
$Q_{\max} F V_{M} \|_{x = 0} + R T N_{\max} \ln x_{m} \|_{V \to ∞}$ ^c	−24.1 kcal/mol
$Q_{\max} F V_{M} \|_{x \to ∞} + R T N_{\max} \ln x_{m} \|_{V \to - ∞}$ ^d	−23.9 kcal/mol
ΔG_model^e	−24.6 kcal/mol
$Q_{\max} F Δ V_{M}$ ^f	−6.7 kcal/mol
$- R T N_{\max} \ln (\frac{x_{m} \|_{V \to ∞}}{x_{m} \|_{V \to - ∞}})$ ^g	−6.5 kcal/mol
$Δ G_{int}$ (model)^h	−6.8 kcal/mol

V_m values were extracted from Q-V curves simulated in the absence and saturation concentrations of ligand (x = 75 µM) using parameters of Fit B of the HA model.

The ligand binding curves at very high (300 mV) and very low (−150 mV) voltages were deduced using the linkage method (Eq. 21), using the binding curve at 0 mV (directly simulated from the model) as the reference curve.

The free-energy change along Path I of thermodynamic cycle, ΔG_Ia + ΔG_Ib.

The free-energy change along Path II of thermodynamic cycle, ΔG_IIa + ΔG_IIb.

ΔG_model is directly obtained from the model parameters: $- R T {{(\frac{J_{0} CDE}{K_{D}})}^{4} L_{0}} .$

Energetic connectivity calculated as: ΔG_IIb − ΔG_Ia.

Energetic connectivity calculated as: G_Ib − ΔG_IIa.

Energetic connectivity evaluated from the model parameters: −RT ln(CE)⁴.

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