Figure 3.

The effect of pH gradients on the PA₆₃ channel instantaneous I–V relationship in the absence and presence of LF (a)–(d). The cis and trans compartments were buffered at either pH 7.2 or 5.5, as indicated in each panel. The LF concentration in the cis chamber was either zero (□) or 1 nM (•). Normalized current for the LF-free (e) and 1 nM LF data (f) highlights relative changes due to pH. Colorization indicates the pH condition as used in (a)–(d), normalized at 10 mV and 120 mV, respectively. The error bars, which represent the standard deviation (n ≥ 7), are generally smaller than the symbols.