Extended Data Fig. 7: Reversal potentials and ion-permeability ratios. | Nature

Extended Data Fig. 7: Reversal potentials and ion-permeability ratios.

From: Cryo-EM structure of the insect olfactory receptor Orco

Extended Data Fig. 7

a, b, VUAA1-evoked whole-cell current from HEK293 cells expressing Orco with 150 mM intracellular CsCl and 150 mM extracellular NaCl (a, blue), or 100 mM extracellular CaCl2 (b, red). c, Summary of reversal potentials (Erev) and permeability ratios (Pion/PCs) for wild-type and mutant Orco and Orco–OR complexes measured under bi-ionic conditions (mean ± s.d.). Erev were measured using N independent cells and corrected for the measured junction potential. Pion/PCs were calculated from Erev using Goldman–Hodgkin–Katz equations (see Methods) with their errors determined by propagation of the standard deviations. Three one-way ANOVA tests were performed using these Erev data followed by Tukey–Kramer multiple comparison tests. (1) Orco selectivity of Na+, K+, Ca2+ and Mg2+ (P values are from comparisons to Na+ Erev). (2) Wild-type and mutant Orco Na+ and Ca2+ selectivity (P values are from comparisons to wild-type Orco with the same ion, Na+ or Ca2+, as appropriate). (3) Orco homomer and Orco–OR heteromer Na+ and Ca2+ selectivity (P values are from comparisons to the Orco homomer with the same ion, Na+ or Ca2+, as appropriate). 245-T is 2,4,5-trimethylthiazole.