Table 3. Predicted free energy changes in the human diamine oxidase (hDAO) dimer by mutation of the heparin-binding motif (HBM).
| rhDAO mutant variant | Stability | Affinity | ||
|---|---|---|---|---|
| ∆∆G (kcal/mol) | ∆∆G (kcal/mol) | |||
| R568S | +0.29 | +3.50 | ||
| R571T | +0.73 | +1.96 | ||
| K575T | +2.13 | +0.55 | ||
| R568S/R571T | +0.60 | +5.21 | ||
| R568S/K575T | +2.42 | +3.93 | ||
| R571T/K575T | +2.86 | +2.52 | ||
| K570G/R571Q/K572T* | +1.53 | +7.77 | ||
The plus sign (+) in the ‘Stability’ column indicates the destabilizing effect on the 3D protein structure, while the plus sign (+) in the ‘Affinity’ column means reduced affinity to heparin hexasaccharide compared to wildtype hDAO. A higher value indicates higher effect on stability or affinity.
*
Corresponds to the HBM in guinea pig, dog, rat, mouse, and Chinese hamster.