Table 4. Summary of the fitting results of the two-state, concentration-dependent anisotropy curves of the endpoints of the detergent desolvation phase with neutral detergentsa,b.
This was determined with three FhuA derivatives and OmpG as well as a panel of five neutral detergents of varying hydrophobic chain and hydrophilic head group. The FP measurements were carried in 200 mM NaCl, 50 mM HEPES, pH 7.4 and at a temperature of 24°C. All data were derived as averages ± SDs of three independent data acquisitions.
| DMc | pd | Kde (mM) | qf (mM−1) | ΔGg (kcal/mol) | Balanceh |
| OmpG | 4.1 ± 1.2 | 1.8 ± 0.4 | 0.064 | −3.7 ± 0.1 | Fadh ≅ Fcoh |
| FhuA ΔC/Δ5L | 3.5 ± 0.5 | 1.7 ± 0.1 | 0.072 | −3.8 ± 0.1 | Fadh ≅ Fcoh |
| FhuA ΔC/Δ5L_25N | 27 ± 3 | 0.9 ± 0.1 | 1.30 | −4.1 ± 0.1 | Fadh ≫ Fcoh |
| FhuA ΔC/Δ7L_30N | 27 ± 6 | 0.9 ± 0.1 | 1.07 | −4.1 ± 0.1 | Fadh ≫ Fcoh |
| CYMAL-4c | pd | Kde(mM) | qf (mM−1) | ΔGg (kcal/mol) | Balanceh |
| OmpG | 6.7 ± 0.1 | 4.6 ± 0.1 | 0.25 | −3.2 ± 0.1 | Fadh > Fcoh |
| FhuA ΔC/Δ5L | 3.7 ± 0.1 | 5.3 ± 0.1 | 0.38 | −3.1 ± 0.1 | Fadh > Fcoh |
| FhuA ΔC/Δ5L_25N | 5.2 ± 0.3 | 5.7 ± 0.1 | 0.28 | −3.1 ± 0.1 | Fadh > Fcoh |
| FhuA ΔC/Δ7L_30N | 2.3 ± 0.9 | 4.5 ± 1.1 | 0.17 | −3.2 ± 0.1 | Fadh > Fcoh |
| OGc | pd | Kd e (mM) | qf (mM−1) | ΔGg (kcal/mol) | Balanceh |
| OmpG | 4.9 ± 0.5 | 11 ± 1 | 0.017 | −2.7 ± 0.1 | Fadh > Fcoh |
| FhuA ΔC/Δ5L | 5.3 ± 0.9 | 13 ± 1 | 0.013 | −2.5 ± 0.1 | Fadh > Fcoh |
| FhuA ΔC/Δ5L_25N | NDi | NDi | NDi | NDi | Fadh ≪ Fcoh |
| FhuA ΔC/Δ7L_30N | NDi | NDi | NDi | NDi | Fadh ≪ Fcoh |
| CHAPSc | pd | Kde (mM) | qf (mM−1) | ΔGg (kcal/mol) | Balanceh |
| OmpG | ~1.6 | < 0.6 | NDi | ~−7.0 | Fadh ≫ Fcoh |
| FhuA ΔC/Δ5L | 1.7 ± 0.6 | 3.3 ± 1.8 | 0.015 | −3.4 ± 0.5 | Fadh > Fcoh |
| FhuA ΔC/Δ5L_25N | NDi | NDi | NDi | NDi | Fadh ≪ Fcoh |
| FhuA ΔC/Δ7L_30N | NDi | NDi | NDi | NDi | Fadh ≪ Fcoh |
| LysoFosc | pd | Kde(mM) | qf (mM−1) | ΔGg (kcal/mol) | Balanceh |
| OmpG | 5.6 ± 1.5 | 0.26 ± 0.03 | 0.41 | −4.9 ± 0.1 | Fadh > Fcoh |
| FhuA ΔC/Δ5L | 9.1 ± 6.2 | 0.47 ± 0.04 | 0.51 | −4.5 ± 0.1 | Fadh > Fcoh |
| FhuA ΔC/Δ5L_25N | 4.5 ± 0.5 | 0.71 ± 0.03 | 0.22 | −4.3 ± 0.1 | Fadh ≅ Fcoh |
| FhuA ΔC/Δ7L_30N | 3.5 ± 0.7 | 0.73 ± 0.04 | 0.13 | −4.3 ± 0.1 | Fadh ≅ Fcoh |
To reach low detergent concentrations below the CMC, the Gdm-HCl-solubilized (FhuA derivatives) or urea-solubilized (OmpG) proteins were refolded at various detergent concentrations above the CMC.
The dose-response equilibrium curves were fitted by the four-parameter Hill equation.
This column indicates the names of the detergents and proteins used in this work.
p is the Hill coefficient.
The apparent dissociation constant, Kd, was determined as the midpoint of the dose-dependent dissociation phase.13
The slope factor or transition steepness was calculated at the midpoint of the dissociation phase.
Free energies were determined using the standard thermodynamic relationship ΔG = RT ln Kd.
The quantitative balance between the adhesive protein-detergent (Fadh) and cohesive detergent-detergent interactions (Fcoh) of the proteomicelles.
Not determined.