We report on a simple method to generate bilayer membranes on a smooth layer of crystalline bacterial cell surface (S-layer) protein lattices, deposited on a microfiltration membrane (MFM), the so-called S-layer ultrafiltration membrane (SUM). Folded bilayers, MFM-, and SUM-supported lipid membranes showed a specific capacitance of 0.6-0.7#mu#F/cm~2. The S-layer produced a stabilizing effect on the lipid membrane; folded ~d MFM-supported membranes ruptured at the application of a first and a second voltage ramp, of the lipid membranes increased significantly in the order MFM -s < folded membrane < of staphylococcal a-hemolysin (#alpha#.HL) was observed in both folded and SUM-supported membranes. The unitary conductance of an (#alpha#HL)pore was similar when reconstituted in folded and in SUM-supported lipid membranes. As an alternative to hybrid and tethered lipid membranes, SUM-supported lipid bilayers provide a biomimetic environment for transmembrane proteins.
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