Figure 2.

Effect of ampicillin on the ion current across a single active reconstituted trimeric OmpF channel (left) and the corresponding all point ion current amplitude histogram (right). OmpF was added to the cis = ground side, the applied voltage was ±100 mV, and the buffer contained 1 m KCl, buffered with 20 mm MES, pH 6.0. Cis/trans ampicillin addition was measured in the same experiments separated by an intensive buffer exchange. A, ion current in the absence of substrate. B, addition of 20 mm ampicillin on the cis side. C, addition of 20 mm ampicillin trans after intensive volume exchange.