title: The effect of hydrostatic pressure on S-layer-supported lipid membranes.
abstract: We report on the behavior of unsupported and surface layer (S-layer)-supported lipid membranes at the application of a uniform hydrostatic pressure. At a hydrostatic pressure gradient higher than 6 N/m(2), unsupported lipid membranes, independent from which side pressurized and S-layer-supported lipid membranes pressurized from the lipid-faced side revealed a pronounced increase in capacitance. A maximal hydrostatic pressure gradient of 11.0 N/m(2) resulted in an almost doubling of the capacitance of the (composite) membranes. S-layer-supported lipid membranes showed a hysteresis in the capacitance versus pressure plot, indicating that this composite structure required a certain time to reorient when the pressure gradient acting from the lipid-faced side was balanced. By contrast, the S-layer-supported lipid membrane pressurized from the protein-faced side revealed only a minute increase in capacitance (C/C(0,max)=1.17+/-0.05), reflecting only minor pressure-induced area expansion. In addition, no hysteresis could be observed, indicating that no rearrangement of the composite membrane occurred. The maximal induced tension was with 4.3+/-0.2 mN/m, significantly higher than that of unsupported (2.5+/-0.3 mN/m) and S-layer-supported lipid membranes pressurized from the lipid-faced side (2.6+/-0.1 mN/m).
authors: Center for Ultrastructure Research and Ludwig-Boltzmann-Institute for Molecular Nanotechnology, Universität für Bodenkultur Wien, Gregor-Mendel-Strasse 33, 1180 Vienna, Austria. bschuste@edv1.boku.ac.at
authors: Bernhard
authors: B
authors: Schuster
authors: Uwe B
authors: UB
authors: Sleytr
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D003460:Crystallization; D025802:Electric Capacitance; D006874:Hydrostatic Pressure; D008051:Lipid Bilayers / Q000737:chemistry*; D008562:Membrane Glycoproteins / Q000737:chemistry; D008854:Microscopy, Electron
chemical_list: D001426:Bacterial Proteins; D008051:Lipid Bilayers; D008562:Membrane Glycoproteins; C055764:S-layer proteins