TABLE 2.
Distance of indole group of Trp residue of HA and gp41 fusion peptide from the center of the bilayer of membrane vesicles
| Peptide | L/P ratio | Vesicles | Distance from bilayer center (Å) |
|---|---|---|---|
| gp41 | 400:1 | DOPC/DOPE/SM/CH, SUV | 8.67 |
| 400:1 | DOPC/DOPE/SM/CH, LUV | 8.60 | |
| 400:1 | DOPC, SUV | 8.65 | |
| 50:1 | DOPC, SUV | 8.60 | |
| 50:1 | DOPC/DOPE/SM/CH, SUV | 8.55 | |
| HA | 400:1 | DOPC/DOPE/SM/CH, SUV | 8.88 |
| 400:1 | DOPC/DOPE/SM/CH, LUV | 8.97 | |
| 400:1 | DOPC, SUV | 9.30 |
To achieve a 50:1 lipid/peptide ratio in some experiments with gp41 peptide, we have added wild-type (no Trp) peptide along with the mutant peptide. This maintained a low surface concentration of Trp-mutant peptide (L/P of 400:1) that allowed us to measure Trp depth in the membrane without interference from high lipid to Trp containing peptide ratio but over all high peptide concentration.