Table 2.
Rate and equilibrium constants for mastoparan X binding to LUVs, at room temperature (about 22°C).
| Lipid Composition |
kon (M−1s−1) |
koffa (s−1) |
koffb (s−1) |
KDc (μM) |
|---|---|---|---|---|
| POPC | (8.0 ± 1.5) × 104 | 32 ± 3 | 16 ± 3 | 300 |
| POPS/POPC 20:80 | (7.2 ± 0.3) × 105 | 7 ± 4 | 0.35 ± 0.15 | 0.5 |
| POPS/POPC 50:50 | (1.0 ± 0.01) × 106 | < 1 | 0.015 ± 0.002 | 0.015 |
a
From association kinetics.
b
From dissociation kinetics.
c
Calculated using kon from association experiments and koff from dissociation experiments except for pure POPC where the average (24 ± 8 s−1) of the values from association and dissociation was used. In the case of POPC we feel confident about the koff obtained from the association kinetics, but in the mixtures the uncertainty in koff is too high, so we used only the value from the dissociation kinetics.