Fig 6.

Kch1 and Kch2 mediate inward K⁺ currents. (A) Averaged patch-clamp traces from protoplasts of the wild-type strain (K432, n = 5, left panel) and the kch1 kch2 double mutant (NZY165, n = 6, right panel), recorded after 10 min incubation in Mg²⁺- and Ca²⁺-free recording buffer (see Materials and Methods). (B) Current-voltage plots for the steady-state currents from panel A, plus controls obtained from the same protoplasts, but with 10 mM extracellular Ca²⁺. Steady-state values calculated from the grand average data, over the interval 2.0 to 2.5 s, along each trace. (C) Plotted differences between corresponding traces of the two panels in panel A. These difference curves are well fitted by the sum of two simple exponentials plus an offset (see equation in Materials and Methods), with the same pair of rate constants for all six plots: α1 = 7.725 s, and α2 = 0.212 s, corresponding to half times of 90 ms and 3.27 s, respectively.