TABLE 4.
Solvent isotope effects of Zn2+-MshB variants
| MshBa,b | pKa1 | pKa2 | V/KH2O/V/KD2O |
|---|---|---|---|
| WTc (H2O) | 7.4 ± 0.1 | 10.5 ± 0.1 | 1.2 |
| WT (D2O) | 7.6 ± 0.1 | 10.6 ± 0.1 | |
| D15A (H2O) | 10.4 ± 0.3 | 0.8 | |
| D15A (D2O) | 10.3 ± 0.3 | ||
| Y142F (H2O) | 7.1 ± 0.05 | 1.0 | |
| Y142F (D2O) | 7.3 ± 0.05 | ||
| H144A (H2O) | 7.1 ± 0.1 | 10.5 ± 0.1 | 5.4 |
| H144A (D2O) | 7.4 ± 0.4 | 10.9 ± 0.4 |
a Apo-MshB was incubated with stoichiometric metal for 30 min prior to activity measurement.
b Substrate 5 (WT, Y142F), 10 (Y142A), or 20 mm (D15A, H144A) GlcNAc.
c Data adapted from Ref. 14.