Table 2.
Thermodynamic parameters of the complex formation between maize Fd and FNRs (wild‐type and mutated L‐FNRs) under different NADP+ concentrations, obtained by ITC (Fig. 5). The n values for the binding are shown in parentheses with K d.
| FNR | NADP+ conc. | |||
|---|---|---|---|---|
| 0 μm | 50 μm | 500 μm | ||
| K d for Fd (μm) | Wild‐type | 1.2 (0.7) | 1.6 (0.7) | 3.7 (0.8) |
| R235Q | 0.87 (0.7) | 0.78 (0.7) | 1.3 (0.9) | |
| R244Q | 0.76 (0.7) | 0.79 (0.8) | 1.1 (1.0) | |
| Y314S | 2.2 (0.7) | 2.6 (0.7) | 2.3 (0.7) | |
|
ΔG
bind
(kcal·mol−1) |
Wild‐type | −8.1 | −7.9 | −7.4 |
| R235Q | −8.3 | −8.3 | −8.1 | |
| R244Q | −8.3 | −8.3 | −8.2 | |
| Y314S | −7.7 | −7.7 | −7.7 | |
|
ΔH
bind
(kcal mol−1) |
Wild‐type | 9.8 | 8.8 | 6.7 |
| R235Q | 8.3 | 7.3 | 6.3 | |
| R244Q | 8.3 | 7.4 | 5.8 | |
| Y314S | 5.6 | 4.3 | 3.6 | |
|
−TΔS
bind
(kcal·mol−1) |
Wild‐type | −17.9 | −16.7 | −14.1 |
| R235Q | −16.5 | −15.6 | −14.5 | |
| R244Q | −16.6 | −15.7 | −14.0 | |
| Y314S | −13.3 | −12.0 | −11.3 | |