Table 2.
Apparent binding affinities (Kd) of VP40 and mutants to lipid vesicles containing phosphatidylserine
Apparent Kd values were measured for WT VP40 and VP40 mutants to liposomes containing 20% POPS. WT VP40 and Δ43 VP40 both display similar binding affinity. Monomeric construct L117R also displays WT levels of affinity. Various mutations within the C-terminal cationic regions abrogate binding to varying degrees. n ≥ 3 for all measurements. (n = 3 for all measurements, except L117R n = 5 and FL WT VP40 n = 6). Error is reported as S.E. of the combined replicates.
| Construct | Predicted effect | Apparent Kd |
|---|---|---|
| FL WT VP40 | WT, full functionality | 35 ± 15 nm |
| Δ43 WT | WT, full functionality | 35 ± 10 nm |
| (Δ43) L117R | Monomer | 70 ± 30 nm |
| (Δ43) I307R | Octomeric ring | >3 μm |
| (Δ43) Δ221–229 | Loop deletion (still dimer) | >6 μm |
| (Δ43) ΔGKKGΔ | Partial loop restoration | >2 μm |
| (Δ43) ΔGEEGΔ | Partial loop restoration, charge reversed | >6 μm |
| (Δ43) ΔGRRGΔ | Partial loop restoration, charge maintained | 400 ± 70 nm |
| (Δ43) K274E/K275E | Charge reversal (still dimer) | >6 μm |
| (Δ43) K274R/K275R | Charge maintained (still dimer) | 600 ± 300 nm |