Fig. 7. Single channel open state dwell times of Cx50, Cx46 and NT domain variants.

a. The i_js (black) and schematic single channel openings (red) and closings (blue) are shown for sheep Cx50-46NT, Cx46, Cx50, Cx46-R9N, Cx50-N9R GJs. Cx50 and Cx50-N9R GJs showed apparently short (asterisks, *) and long (arrows) open events, as well as more open events than the other GJs. Note that the first and the last open events were excluded as they likely under represent the open dwell time (e.g. exist in open state before or after the V_j pulse). Our V_j-pulse duration (7 s) may not be sufficient to reach a true steady state and the open event properties might be slightly different from the fully stable i_js of the studied GJs. b. The averaged open dwell time for each GJ were plotted at different V_js. The number of events analyzed ranged from 33–832 from 2–7 cell pairs. Note that the open dwell time is plotted in logarithmic scale to show large differences among these GJs. The ranking of the open dwell times of these GJs from high to low is: Cx50-46NT > Cx46 > Cx50 > Cx46-R9N > Cx50-N9R. c. The open dwell time for all open events for Cx50 and Cx50-N9R were plotted in a logarithmic histogram with 5 bins/decade and fitted with two-exponential log components. The two time constant (τ) values represent the corresponding short and long open events for Cx50 (top histograms) and Cx50-N9R (bottom green histograms) are displayed, with their relative proportions in parentheses. The τ_mean values were calculated by taking the weighted average of the two τ values using the area under each peak for each of these variants at a specific V_j.