Fig. 2.
Fitting extended beta distributions to measured amplitude histograms. (A) 4-state Markov model used for the generation of the theoretical amplitude histograms (extended beta distributions) by simulated current traces. (B,C) Representative current amplitude histograms of KcvNTS in 0.1 M KCl, pH 7 (gray) and the best fit with the model in (A) (black). Regions dominated by one of the closed states F, M or S are indicated. At +160 mV (B), both the closed (at 0 pA) and open peak (at 14.6 pA) are well defined. At -160 mV (C), the open peak is extremely broadened and skewed, corresponding to the large, asymmetric open-channel noise in the current trace (Fig. 1C).