A patch-clamp study of ion channels of inner and outer membranes and of contact zones of E. coli, fused into giant liposomes. Pressure-activated channels are localized in the inner membrane.

Inner and outer membranes of Escherichia coli and contact zones were isolated and fused separately with giant liposomes amenable to patch-clamp recording. Different types of large pressure-activated channels were localized in the inner membrane fraction which also contained smaller, pressure-insensitive channels. The outer membrane contained pressure-insensitive channels with large conductances and long opening and closing times which are likely to be porins. Large channels were also observed in contact zones.