![Allosteric factor, n, of the inverted coupling model modulates gating polarity. (A) Gating scheme of the inverted coupling model. C and O are when the pore is closed and opened, respectively. VD and VH are the voltage sensor upon membrane depolarization and upon membrane hyperpolarization, respectively. K1 is a voltage-dependent equilibrium state constant for movement of the voltage sensor. K2 is voltage-independent for opening and closure of the pore. n is the allosteric factor. Equations for calculating the PO−V curves are described in Materials and methods. (B) Family of PO−V plots based on the gating scheme in A. The K10 = 1, q1 = −1, and K2 = 1 are the same for all except for n, which is varied as shown in the legend. (C)PO−V scatter plot of hEAG (adapted from Cowgill et al. [2019]). These data were fitted (dashed black line) with the following parameters: K10 = 22.4, q1 = −1.46, and K2 = 143. n = 3.38 × 10−5. PO-V plots in blue correspond to varying values of n when n is <1. (D)PO−V scatter plot of mHCN1 (adapted from Cowgill et al. [2019]). These data were fitted (dashed black line) with the following parameters: K10 = 1.13 × 10−4, q1 = −2.03, and K2 = 0.0139, n = 1,550. PO−V plots in red correspond to varying values of n when n is >1.](https://cdn.rupress.org/rup/content_public/journal/jgp/158/1/10.1085_jgp.202513849/1/jgp_202513849_fig2.png?Expires=1772591579&Signature=DW1YbgrYo4lrvokvxYTEtT1ib~SZimU-cJ0FeOWOCyxuijqrOYLDhlLpTWUggrVzsNmguYLotQ9TEXhMZotAmjEOCjc5PVv7ebXrUtjLWTMZL4xStl0f4lN90mG0aK3UwjOOMHeLxdbirrCRknvm189NgJzjkuH5QaYFSpL7Ozge9-0ViaMEbp5~hf~Fa9pxzTcwyxa2F7-vCxmHpUR3HkQ4JwUATOGjhk9sDAyNPjSQxMv0OJKxldCmG8IJXz~mkUdmUc5SF4nQNNHe4R15RhqCzjuvKAeC63DiVav72HrG2Tvah1D7QNTsyXzVnIxDK9CG1A2ckXkO15oLK0L4Dg__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Allosteric factor, n, of the inverted coupling model modulates gating polarity. (A) Gating scheme of the inverted coupling model. C and O are when the pore is closed and opened, respectively. VD and VH are the voltage sensor upon membrane depolarization and upon membrane hyperpolarization, respectively. K1 is a voltage-dependent equilibrium state constant for movement of the voltage sensor. K2 is voltage-independent for opening and closure of the pore. n is the allosteric factor. Equations for calculating the PO−V curves are described in Materials and methods. (B) Family of PO−V plots based on the gating scheme in A. The = 1, q1 = −1, and K2 = 1 are the same for all except for n, which is varied as shown in the legend. (C)PO−V scatter plot of hEAG (adapted from Cowgill et al. [2019]). These data were fitted (dashed black line) with the following parameters: = 22.4, q1 = −1.46, and K2 = 143. n = 3.38 × 10−5. PO-V plots in blue correspond to varying values of n when n is <1. (D)PO−V scatter plot of mHCN1 (adapted from Cowgill et al. [2019]). These data were fitted (dashed black line) with the following parameters: = 1.13 × 10−4, q1 = −2.03, and K2 = 0.0139, n = 1,550. PO−V plots in red correspond to varying values of n when n is >1.