XB-IMG-170221
Xenbase Image ID: 170221
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Figure 1. VDP of zELK channels.(A) Homology model of the structure of the zELK channel illustrating the intersubunit eag domain-CNBHD interaction (side-view parallel to the plasma membrane), based on the cryo-EM structure of the rEAG1 channel (PDB code: 5K7L) (Whicher and MacKinnon, 2016). Red arrow highlights the direct eag domain-CNBHD interaction. (B) Representative current-voltage (I–V) recordings of zELK channels in the cell-attached configuration using the voltage protocol on the left. The red trace is the double-exponential fitting of the current elicited by a +120 mV voltage pulse (τ1 = 4 ms and τ2 = 206 ms). (C) Representative conductance-voltage (G–V) curves of zELK channels in the cell-attached configuration without and with a +60 mV prepulse. The dashed curve is the same data as the black solid curve but normalized to the amplitude of the red curve. (Right) Summary of the V1/2 of the G-V curves from multiple patches (n = 4–14). (D) zELK currents (right) elicited by a voltage protocol with increasing durations of +60 mV pulse (left). The deactivation time constants for the red traces are 8.5 and 22.9 ms respectively). (E) A 6-state kinetic model for the VDP of KCNH channels. (F–H) Simulated data based on the 6-state model for zELK channels using QuB software (State University of New York at Buffalo) using the same protocols as panels B–D respectively. Voltage-dependent rate constants are given by k(V) = k0 exp(k1V), where V is voltage, k0 is the rate at 0 mV, and k1 the voltage dependence of the rate. For the forward rate constant α of the voltage-dependent transition: k0 = 80 s−1 and k1 = 0.025 mV−1; for the reverse rate constant β of the voltage-dependent transition: k0 = 600 s−1 and k1 = −0.025 mV−1. For the rate constant of the VDP transition step: ε = 35 s−1. For the other transitions illustrated: γ = 60 s−1, d = 200 s−1, ο = 5000 s−1, κ = 70 s−1.DOI:
http://dx.doi.org/10.7554/eLife.26355.003Figure 1—figure supplement 1. Dendrogram of KCNH channel family.Phylogenetic tree illustrating the evolutionary relationships of EAG, ERG and ELK channels in the KCNH channel family.DOI:
http://dx.doi.org/10.7554/eLife.26355.004 Image published in: Dai G and Zagotta WN (2017) © 2017, Dai et al. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution license Larger Image Printer Friendly View |