Figure 3. Tim23^N150A displays reduced cation preference.

(A)/(B) Tim23- (A) or Tim23^N150A-containing (B) proteoliposomes were fused with planar lipid bilayers and single-channel activity was characterized by electrophysiological current recordings. (C) Gating event histograms for Tim23 (left) and Tim23^N150A (right) were calculated from constant-voltage recordings (as depicted in A) with at least 2000 gating events each. The three most prominent classes of conductance changes were modeled with a Gaussian fit. (D) I-V curves at asymmetrical buffer conditions were recorded for Tim23 (left) and Tim23^N150A (right) with indicated reversal potential U_rev for 12.5-fold KCl-gradient. (E)/(F) I-V curves (left) and open probabilities (right) were determined for bilayer incorporated Tim23 (E) or Tim23^N150A (F) before (black) and after (red) addition of 700 nM Tim50^IMS to IMS-side of the channel. Error bars represent standard deviation (SD, n = 3).