PMC

DSC of pure DPPG, in the absence and presence of MSI-1254, before and after 24 h and 96 h incubation at 4°C. Lipid films were hydrated with 20 mM PIPES, 1 mM EDTA, 140 mM NaCl, pH 7.4. The scan rate was 1°/min. Odd numbers are heating scans and even numbers are cooling scans. The arrow indicates the conversion of the subgel phase to a higher temperature crystalline phase. Lipid/peptide ratio was 20. Odd numbers are heating scans and even numbers are cooling scans.

DSC of DPPG/TOCL 50:50 in absence and presence of MSI-1254. Lipid films were hydrated at room temperature with 20 mM PIPES, 1 mM EDTA, 140 mM NaCl, pH 7.4 or with a solution of MSI-1254 in this buffer at a lipid to peptide ratio of 20. The scan rate was 1°/min, and the temperature range from 0 to 45°C. Freshly prepared samples or samples incubated for 24 h at 4°C. Odd numbers are heating scans and even numbers are cooling scans.

DSC in DMPG/TOCL 75:25 in absence and presence of peptides: Lipid films were hydrated at room temperature, with 20 mM PIPES, 1 mM EDTA, 140 mM NaCl, pH 7.4 or with peptide solutions in this buffer at a lipid to peptide ratio of 20. The scan rate was 1°C/min and the temperature range from 0 to 35°C. Odd numbers are heating scans and even numbers are cooling scans. When peptide is present, the first heating and cooling cycle in each figure corresponds to that of the lipid mixture without peptide, followed by two or three cycles containing the corresponding peptide.

DSC in pure DMPG in absence and presence of peptides. Lipid films were hydrated at room temperature with 20 mM PIPES, 1 mM EDTA, 140 mM NaCl, pH 7.4 or with peptide solutions in this buffer, at a lipid to peptide ratio of 20. The scan rate was 1°/min, and the temperature range from 0 to 50°C. Odd numbers are heating scans and even numbers are cooling scans. When peptide is present, the first heating and cooling cycle in each figure corresponds to that of the lipid mixture without peptide, followed by two or three cycles containing the corresponding peptide.

DSC of PLL (left panels) and PLA (right panels) in DMPG/TOCL 75:25 (upper panels) or in DMPG (lower panels). Lipid films were hydrated at room temperature with 20 mM PIPES, 1 mM EDTA, 140 mM NaCl, pH 7.4 or with polymer solution in this buffer at a lipid to polymer ratio of 500 for PLL and 400 for PLA in the lipid mixture and at lipid to polymer ratio of 200 for PLL and 400 for PLA in pure DMPG. The scan rate was 1°C/min and the temperature range was from 0 to 35°C. Odd numbers are heating scans and even numbers are cooling scans. When polymer is present, the first heating and cooling cycle in each figure corresponds to that of the lipid mixture without peptide, followed by three or two cycles in the presence of the corresponding polymer.

DSC in DMPG/TOCL 75:25 after incubation at 4°C in absence and presence of peptides. (A) 24 h incubation. (B) 72 h incubation. Lipid films were hydrated with 20 mM PIPES, 1 mM EDTA, 140 mM NaCl, pH 7.4 or with peptide solutions in this buffer at a lipid to peptide ratio of 20. The scan rate was 1°C/min, and the temperature range from 0 to 45°C. Odd numbers are heating scans and even numbers are cooling scans. Primed numbers correspond to lipid with peptide. When peptide is present, the first heating and cooling cycle in each figure corresponds to that of the lipid mixture without peptide, followed by two or three cycles containing the corresponding peptide.