Solid supported stacks of typically 1,000 aligned DLPC bilayers with a cholesterol (Chol) content of 5% and differing amounts of the respective peptide species were prepared from stock solutions following procedures described in the literature (Seul and Sammon 1990) . Polished and cleaned (sonication in MeOH and ultrapure water, 15 min each) Si wafers with h100i orientation and a thickness of 625 lm (Silchem, Freiberg, Germany) were used as substrates. Stock solutions of DLPC and Chol in chloroform were prepared at concentrations of 40 and 3 mg/ml, respectively. Peptide stocks were composed of MeOH/DCM/EtOH 4/3/3 (v/v/v) at 6 mg/ml concentration. For P/L ratios between 1/10 and 1/50 in a definite volume of 80 or 150 ll, mixtures of stock solutions were spread onto cleaned, horizontally mounted silicon substrates with dimensions of 10 9 15 mm (80 ll, beamline experiments) or 15 9 25 mm (150 ll, in-house experiments), respectively. The coated Si wafers were covered with a watch glass, and the solvent was carefully evaporated in a flowbox overnight to prevent film rupture and fast dewetting. Subsequently, reduced pressure was applied for an additional 12 h. The resulting film-covered substrates were stored at 4°C until use.