Fig. 2: Conformational changes of pore opening.

a Representative ELIC currents in response to 10 mM cysteamine of excised patches from 2:1:1 POPC:POPE:POPG giant liposomes (black = WT, red = ELIC5, −60 mV holding voltage). The ELIC5 currents show sustained response to 10 mM cysteamine, followed by slow deactivation with the removal of cysteamine. b Inset that shows ELIC5 (red) single channel currents taken from the deactivation trace (i.e., channel closure) or WT (black) single channel currents in the presence of 10 mM cysteamine. c Cryo-EM density map of ELIC5 in 2:1:1 POPC:POPE:POPG nanodiscs + 10 mM cysteamine (grey) with outer leaflet lipid density (yellow) and black lines approximating the bilayer. d View of the pore lining M2 helix from the extracellular side showing 16’ (F247) and 9′ (L240) side chains from WT apo, WT CA (WT + 10 mM cysteamine), ELIC3 CA (ELIC3 + 10 mM cysteamine), and ELIC5 CA (ELIC5 + 10 mM cysteamine). All are structures in 2:1:1 POPC:POPE:POPG nanodiscs. e Ion permeation pathway as determined by HOLE⁷⁶ of the same structures shown in d. The ELIC5 CA structure shows rotamer 2 for Q233 (see Supplementary Fig. 8 for a comparison of rotamers 1 and 2). Labeled are 16′, 9′, and 2′ side chains which form the narrowest portions of the pore in different structures. f Pore radius as a function of distance along the pore axis for the same structures as d and e.