Table 3.
Thermodynamic Data for the Binding of Q8 to MXA versus MXGGY and MXZGY Peptides
| peptide | Kd (μM)b | ΔHb (kcal mol−1) | −TΔSc (kcal mol−1) |
|---|---|---|---|
| MYAa | 0.25 (±0.01) | −18.2 (±0.2) | 9.3 (±0.1) |
| MYGGY | 0.16 (±0.01) | −19.4 (±0.4) | 10.1 (± 0.4) |
| MLAa | 0.72 (±0.09) | −15.8 (±2.5) | 7.4 (±2.5) |
| MLGGY | 0.30 (±0.01) | −16.9 (±0.1) | 7.9 (±0.1) |
| LMAa | 0.60 (±0.11) | −12.1 (±0.2) | 3.5 (±0.2) |
| LMGGY | 0.16 (±0.02) | −22.9 (±0.2) | 13.5 (±0.3) |
| MKAa | 2.6 (±0.4) | −13.7 (±0.5) | 6.0 (±0.6) |
| MKGGY | 0.42 (±0.02) | −16.9 (±0.1) | 8.2 (±0.1) |
| MKAGY | 0.89 (±0.07) | −16.7 (±0.3) | 8.3 (±0.4) |
| MKVGY | 6.1 (±0.4) | −15.9 (±0.5) | 8.8 (±0.5) |
a
Shown again for reference.
b
Mean values measured from at least three ITC experiments at 300 K in 10 mM sodium phosphate, pH 7.0. Standard deviations are in parentheses.
c
Entropic contributions to the free energy of binding were calculated from the Kd and ΔH values, with error propagated from those of Kd and ΔH.