Table 2. Thermodynamics parameters of the Lα-to-HII phase transition of peptide-free and peptide-containing DiPoPE liposomes at low (0 mM NaCl) and high (150 mM NaCl) ionic strength.
| Sample | ΔHH (cal/mol) | TH (°C) | ΔT1/2 (°C) |
|---|---|---|---|
| DiPoPE (0 mM NaCl) | 136 | 44.3 | 2.0 |
| +0.2 mol% SARSFP | 91 | 47.9 | 2.4 |
| +0.5 mol% SARSFP | 74 | 50.2 | 3.7 |
| +0.2 mol% SARSIFP | 92 | 45.4 | 1.7 |
| +0.5 mol% SARSIFP | 40 | 44.6 | 2.2 |
| DiPoPE (150 mM NaCl) | 107 | 47.5 | 2.3 |
| +0.2 mol% SARSFP | 101 | 48.7 | 3.1 |
| +0.5 mol% SARSFP | 44 | 50.1 | 3.4 |
| +0.2 mol% SARSIFP | 83 | 43.7 | 2.5 |
Estimated uncertainties: ΔHH (8–15%), TH (0.2 °C), ΔT1/2 (0.3 °C).
The high inaccuracy on the values of ΔHH was mainly due to extensive lipid aggregation of peptide-free and peptide-containing DiPoPE vesicles from different sample preparations. However, not only the TH was reproducible from different samples, but also the general trend of decreasing the ΔHH of the transition in the peptide-containing DiPoPE samples was observed in all experiments.