. 2023 Feb 8;155(5):e202213170. doi: 10.1085/jgp.202213170

Table 2.

Parameters used for simulations in Fig. 8 using the model in Fig. 1

	Wt (0 cAMP)	Wt (100 cAMP)	QWE-3G (0 cAMP)	QWE-3G (100 cAMP)
k	3 s⁻¹	3 s⁻¹	3 s⁻¹	3 s⁻¹
V_1/2	−60 mV	−60 mV	−10 mV	−10 mV
z	1 e₀	1 e₀	1 e₀	1 e₀
k_open	1 s⁻¹	2 s⁻¹	50 s⁻¹	100 s⁻¹
k_close	50 s⁻¹	50 s⁻¹	50 s⁻¹	50 s⁻¹
k_in	0.5 s⁻¹	0 s⁻¹	0.5 s⁻¹	0 s⁻¹
k_rec	5 s⁻¹	5 s⁻¹	50 s⁻¹	50 s⁻¹
L	2.1	2.1	1.2	1.2
M	2.1	2.1	2.1	2.1

To simulate the QWE-3G mutant, we made the following changes: the mutation QWE-3G shifts the voltage dependence of S4 movement (V_1/2) to more positive voltages. Mutations in the C-terminal end of S4 destabilize the closed state of the gate, thereby increasing the rates of leaving the closed state (k_open) and leaving the inactivated state (k_rec) to the open state. Mutations in the C-terminal end of S4 have also been shown to decrease the coupling between S4 and the gate (L). To simulate the overall increase in open probability by cAMP binding, the opening rate k_open was increased by a factor of 2 for both wt and QWE-3G channels in the presence of cAMP.