Table 1.
Average best fits of ITC experimental data for BCA/Cu+ titrations at 25 °C to a one-site binding modela
| Buffer | pH | [MeCN] (mM) | n | ΔH kJ mol–1 (kcal mol–1) | KITC (×106) |
|---|---|---|---|---|---|
| BCA → CuI | |||||
| Tris | 7.5 | 25 | 2.11 ± 0.05 | –28 ± 1 (–6.7 ± 0.2) | 2.2 ± 0.2 |
| Tris | 8.0 | 10b | 1.96 ± 0.04 | –27.3 ± 0.8 (–6.5 ± 0.2) | 2.3 ± 0.3 |
| Tris | 8.0 | 25 | 2.02 ± 0.01 | –27.0 ± 0.2 (–6.45 ± 0.05) | 2.0 ± 0.3 |
| Tris | 8.0 | 500 | 1.9 ± 0.1 | –28 ± 1 (–6.7 ± 0.2) | 3.6 ± 0.3 |
| Tris | 8.0 | 1000 | 2.01 ± 0.09 | –27.1 ± 0.7 (–6.5 ± 0.1) | 1.1 ± 0.1 |
| Tris | 8.5 | 25 | 1.98 ± 0.03 | –27.0 ± 0.5 (–6.5 ± 0.1) | 0.8 ± 0.1 |
| Bis-Tris | 6.0 | 25 | 2.04 ± 0.01 | –38.0 ± 0.2 (–9.09 ± 0.05) | 2.4 ± 0.1 |
| Bis-Tris | 7.0 | 25 | 1.95 ± 0.01 | –37.0 ± 0.4 (–8.84 ± 0.09) | 2.3 ± 0.5 |
| HEPES | 7.0 | 25 | 2.08 ± 0.01 | –37.0 ± 0.5 (–8.8 ± 0.1) | 2.4 ± 0.4 |
| CuI → BCA | |||||
| Tris | 8.0 | 500 | 0.51 ± 0.01 | –53.2 ± 0.2 (–12.81 ± 0.05) | 2±3 |
| HEPES | 7.0 | 500 | 0.48 ± 0.01 | –72.4 ± 0.5 (–13.3 ± 0.1) | 5±3 |
a
All data collected in 25 mM buffer and 100 mM NaCl. Fit parameters represent the average of at least three independent titrations.
b
[Cu+] in reaction cell = 50 μM to ensure Cu+ stability. All other reactions are conducted with 125 μMCu+.