Table 1.
Activity of AlnA and AlnB variants determined with the Malachite green assay
| Variant | Released PO4 (nmol) | Activity (%) |
| AlnA | ||
| Native | 9.2 ± 0.4 | 100 |
| E29A | 0.39 ± 0.51 | 4.2 |
| E29Q | 0.05 ± 0.49 | 0.5 |
| K86A | 0.48 ± 0.51 | 5.2 |
| H130A | 1.1 ± 0.5 | 12 |
| D138A | 1.1 ± 0.3 | 12 |
| K159A | 0.35 ± 0.52 | 3.8 |
| K159R | 0.39 ± 0.51 | 4.2 |
| AlnB | ||
| Native | 1.2 ± 0.1 | 100 |
| D15A | 0.04 ± 0.02 | 3.3 |
| D15N | 0 | 0 |
| D17A | 0.02 ± 0.01 | 1.7 |
| Y79A | 0.66 ± 0.06 | 55 |
| K119A | 0.05 ± 0.03 | 4.2 |
| K119R | 0.02 ± 0.01 | 1.7 |
The coupled AlnA–AlnB reactions were performed in triplicate, with each individual sample assayed in duplicate, and the value for the blank reaction was subtracted. SD for each assay result is shown in SI Text.