Figure 5

Gating characteristics of CgMscCG in the C. glutamicum and E. coli spheroplast membranes. (A) Current traces of CgMscCG in the C. glutamicum membranes at the pipette voltages of +40 mV (black) and +100 mV (red). Arrow heads indicate the opening (downward) and closing (upward) of CgMscCG. Gating hysteresis was determined by the gating threshold ratio between the first closing and opening pressure (dotted lines) and is plotted in the range of pipette voltages from −100 mV to +100 mV. Bars represent SEM (n = 4). (B) Gating hysteresis of CgMscCG in the E. coli membrane. Channel currents at the pipette voltages of +40 mV (black) and +100 mV (red) are shown on the left and voltage dependence of the gating threshold ratio is shown as in (A) on the right. Note that the pressure profile is different from (A) because of the strong gating hysteresis of CgMscCG in the C. glutamicum membrane. (C) Current rectification of CgMscCG in the C. glutamicum membrane. Current traces upon the application of a pressure ramp at the pipette voltages of +60 mV and −60 mV are shown in black and red, respectively (left). O1-5 indicates the number of open channels in the patch membrane. A current-voltage relationship of CgMscCG in the C. glutamicum membrane is shown on the right. Bars represent SEM (n = 6). (D) CgMscCG currents recorded in the E. coli membrane. O1-7 indicates the number of open channels in the membrane patch.