Table 2.
Properties of AfFabI carboxyl-terminal truncation mutants
| Property | AfFabIa(1–289) | AfFabI(1–273) | AfFabI(1–269) | AfFabI(1–265) | AfFabI(1–261) |
|---|---|---|---|---|---|
| Complementation | |||||
| fabI(Ts) | Yes | Yes | Yes | No | No |
| Biophysical properties | |||||
| s20 | 6.59 | 6.40 | 6.37 | 6.18 | 6.11 |
| Thermal stability | |||||
| Ligand-free (°C) | 47.9 ± 0.1 | 46.0 ± 0.2 | 45.0 ± 0.1 | 48.8 ± 0.2 | 52.1 ± 0.4 |
| + NADH (°C) | 54.8 ± 0.2 | 52.1 ± 0.2 | 50.5 ± 0.3 | 49.3 ± 0.2 | 51.4 ± 0.2 |
| ΔT (°C) | 6.9 ± 0.2 | 6.1 ± 0.3 | 5.5 ± 0.4 | 0.5 ± 0.4 | −0.7 ± 0.6 |
| Biochemical properties | |||||
| NADH K0.5 (μm) | 52.8 ± 3.0 | 160.3 ± 22.2 | 127.1 ± 10.9 | 291.9 ± 31.8 | 1225.0 ± 47.5 |
| hb | 2.1 ± 0.2 | 1.4 ± 0.2 | 1.3 ± 0.1 | 1.0 ± 0.1 | 2.6 ± 0.2 |
| Vmax/[ET]c (min−1) | 6.45 ± 0.19 | 6.57 ± 0.24 | 7.26 ± 0.19 | 6.46 ± 0.21 | 6.63 ± 0.18 |
| Vmax/[ET]/K0.5d (10−3 μmol−1 min−1) | 122.12 ± 3.64 | 40.97 ± 1.51 | 57.13 ± 1.52 | 22.14 ± 0.71 | 5.41 ± 0.15 |
aAfFabI(1–289) is the full-length, wildtype protein.
bHill number.
cTurnover number. [ET] = total enzyme concentration.
dA measure of catalytic efficiency.