Dissociation constant (Kd) and stoichiometry ratio (N) of recombinant MBP-PDI-b′xa′ and its mutants to rutin. Site-directed mutagenesis of MBP-fused human PDI proteins were designed based on in silico simulations of rutin bound to human PDI. The interactions between rutin and MBP-PDI-b′xa′ proteins were measured with isothermal titration calorimetry (ITC) method. Data were expressed as mean ± S.D.
| N | K d (μM) | ΔG (kcal mol−1) | |
|---|---|---|---|
| wt | 0.86 ± 0.02 | 2.39 ± 0.45 | −7.71 ± 0.48 |
| K328E | 0.86 ± 0.02 | 2.29 ± 0.36 | −7.72 ± 0.31 |
| H354A | 0.72 ± 0.03 | 5.98 ± 1.08 | −7.15 ± 0.86 |
| L355R | 1.93 ± 0.03 | 3.50 ± 0.39 | −7.46 ± 0.23 |
| E359A | 1.18 ± 0.03 | 4.10 ± 0.74 | −7.39 ± 0.49 |
| E359K | 1.21 ± 0.02 | 4.48 ± 0.58 | −7.31 ± 0.45 |