Table 3.
Thermodynamic parameters for the binary interaction of hAIF∆1-101 variants with CHCHD4, CypA, and DNA.
| hAIF∆1-101 form | Titrating ligand | K d (μM) | ΔH (kcal/mol) | ΔG (kcal/mol) | -TΔS (kcal/mol) |
|---|---|---|---|---|---|
| WTox and W196Yox | CHCHD4 | No detected binding | |||
| W196Aox | CHCHD4 | 0.4 | 9.6 | -8.4 | -18.0 |
| WT CTC | CHCHD4 | 0.2 | -20.1 | -8.7 | 11.4 |
| W196Y CTC | CHCHD4 | 2.1 | -8.2 | -7.5 | 0.7 |
| W196A CTC | CHCHD4 | 0.5 | -5.9 | -8.3 | 14.2 |
| WTox | CypA | 2.7 | -24.5 | -7.3 | 17.2 |
| W196Yox | CypA | 1.0 | 17.0 | -7.9 | -24.9 |
| W196Aox | CypA | 1.8 | 27.3 | -7.6 | -34.9 |
| WTox | dsDNA | 1.6 | 4.8 | -7.6 | -12.4 |
| W196Yox | dsDNA | 6.9 | 19.2 | -6.8 | -26.0 |
| W196Aox | dsDNA | 5.8 | 15.0 | -6.9 | -22.0 |
Values obtained from ITC assays at 25°C in 50 mM potassium phosphate, pH 7.4. n is the calculated biding stoichiometry. The thermodynamic parameters were calculated by Kd = (Ka)−1, ΔG = RT.lnKd, and −TΔS = ΔG − ΔH. Errors considered in the measured parameters (±20% in Kd and ±0.3 kcal/mol in ΔH and −TΔS) were taken larger than the standard deviation between replicates and the numerical error after the fitting analysis.