FIGURE 3.

Amide I band in polarized ATR spectra from hydrated aligned phospholipid membranes containing gramicidin A at a lipid/peptide ratio of 10:1 mol/mol. Solid and dashed lines are for radiation polarized parallel and perpendicular to the plane of incidence, respectively. (A) In phosphatidylcholine (DMPC) membranes; (B) in phosphatidylserine (DMPS) membranes; (C) in phosphatidylglycerol (DMPG) membranes; and (D) in phosphatidylethanolamine (DMPE) membranes. Membranes are hydrated in D₂O (DMPC and DMPE), or in D₂O buffer: 10 mM Hepes, 1 M NaCl, pH 7.8 (DMPS and DMPG); temperature 10°C. Dotted lines are the components obtained from band fitting, except those overlaying the solid and dashed lines, which are the sum of the fitted components.