Figure 7.

The D112V/V116S mutant is permeable to Cl⁻. Replacing CH₃SO₃⁻ with Cl⁻ increased outward current in families (A and C) and shifted the tail current reversal potential negatively (B and D). All measurements were in a COS-7 cell at symmetrical pH 5.5 with TMA⁺ CH₃SO₃⁻ solutions or external TMA⁺ Cl⁻ solutions, as indicated. Pulses were applied in 10-mV increments from −40 to 80 mV for families and in 10-mV increments for tail currents as indicated. The cell was held at −30 mV and returned to V_hold after pulses. The same calibration bars apply to families (A and C) and tail currents (B and D).