TABLE 4.
HET-C2 binding constants for glycolipids
Kd values were calculated from changes in emission intensity and from the λmax blue shift. Kd I is calculated from the emission intensity changes resulting from the addition of vesicles containing glycolipid after correction against vesicles lacking glycolipid. Saturation of glycolipid binding is indicated by cessation of the λmax blue shift. Kd II represents values calculated from emission intensity changes occurring even after saturation of the λmax blue shift and corresponding to both glycolipid binding and HET-C2 partitioning to the membrane interface. Note that all of the calculations were performed assuming that only half of the glycolipid in the vesicles is available for binding.
| Vesicle composition |
Kd |
||
|---|---|---|---|
| Wavelength shift/Δν | Intensity change |
||
| I | II | ||
| GlcCer/POPC | 0.177 ± 0.10 | 0.13 ± 0.10 | 0.92 ± 0.32 |
| GalCer/POPC | 0.108 ± 0.01 | 0.11 ± 0.01 | 0.60 ± 0.03 |
| LacCer/POPC | 0.13 ± 0.04 | 0.41 ± 0.27 | 1.49 ± 0.43 |
| POPC | 5.26 ± 1.39 | ||