TABLE 1.
Peptide sequences, their molecular mass, retention time, and relative hydrophobicity (see legend for definitions)
| Peptide | Sequence | MW (Da): c/m | RT (min) | W-Oct ΔGWO | W-IF ΔGWIF | IF-Oct ΔΔGIFO |
|---|---|---|---|---|---|---|
| GS10WW | Cyclo-(VKLdWPVKLdWP) | 1246.76 / 1247.03 | 32.0 | −1.72 | −1.80 | +0.08 |
| GS10FW | Cyclo-(VKLdFPVKLdWP) | 1207.74 / 1207.69 | 31.7 | −1.34 | −1.08 | −0.26 |
| GS | Cyclo-(VOLdFPVOLdFP) | 1140.69 / 1140.77 | 31.4 | −0.96 | −0.36 | −0.60 |
| GS10WY | Cyclo-(VKLdWPVKLdYP) | 1223.70 / 1224.06 | 30.5 | −0.34 | −0.89 | +0.63 |
| GS10FY | Cyclo-(VKLdFPVKLdYP) | 1184.72 / 1184.17 | 30.2 | −0.04 | −0.17 | +0.13 |
| GS10YY | Cyclo-(VKLdYPVKLdYP) | 1200.74 / 1200.82 | 28.8 | +1.04 | +0.02 | +1.02 |
Peptide sequences: O represents ornithine, and d represents the D-enantiomer. Molecular mass: Calculated (c), and measured (m) molecular masses of peptides, using electrospray mass spectrometry. MW is the molecular mass. Molecular masses are measured as [M+H]+. Retention times: (RT) on the RP-HPLC C4 column. Solvents A (water + 0.05% TFA) and B (acetonitrile + 0.05% TFA) were used at a flow rate of l mL/min with a gradient from 100% A →100% B in 50 min. Hydrophobicity: Relative free energy of transfer of the peptides from water to octanol (ΔGWO), water to POPC bilayer interface (ΔGWIF), and the difference between the two (ΔΔGIFO) were calculated on the basis of whole-residue hydrophobicity scales (16). The free energy of transfer of peptide bonds to octanol and the effect of the peptide backbone structure, which are comparable for all peptides, were not considered in these calculations. Note that W stands for water; Oct stands for octanol; IF stands for interfacial; and IF-Oct stands for interfacial to octanol; free energies are in kcal/mol.