Table 2.
Observed rate constants for E. coli CheY variants.
| Protein | kdephos (min−1) a | K1/2 (mM) b | kdephos/K1/2 (M−1s−1) c | ||
|---|---|---|---|---|---|
|
| |||||
| PAM | AcP | PAM | AcP | ||
| CheY wild-type | 4.0 ± 0.5 | 8.6 ± 2 | 7.0 ± 0.7 | 7.8 ± 2 | 9.5 ± 1 |
| CheY A113P | 4.7 ± 0.2 | 1.6 ± 0.1 | 2.2 ± 0.2 | 63 ± 5 | 36 ± 0.9 |
| CheY M17A | 1.7 ± 0.1 | 2.3 ± 0.2 | - | 12 ± 2 | - |
| CheY M17A A113P | 3.2 ± 0.1 | 0.68 ± 0.05 | - | 79 ± 7 | - |
| CheY L24S | 6.2 ± 0.1 | 2.5 ± 0.5 | - | 41 ± 5 | - |
| CheY L24S A113P | 6.4 ± 0.4 | 2.0 ± 0.1 | - | 55 ± 5 | - |
| CheY V86S | 4.6 ± 0.2 | 4.8 ± 0.6 | - | 16 ± 2 | - |
| CheY V86S A113P | 4.8 ± 0.2 | 6.9 ± 0.2 | - | 12 ± 1 | - |
| CheY V108T | 4.1 ± 0.4 | 5.6 ± 0.3 | - | 12 ± 1 | - |
| CheY V108T A113P | 5.8 ± 0.2 | 1.3 ± 0.09 | - | 74 ± 6 | - |
| CheY F111V | 7.6 ± 0.3 | 0.89 ± 0.06 | - | 140 ± 10 | - |
| CheY F111V A113P | 6.7 ± 0.08 | 0.82 ± 0.04 | - | 140 ± 8 | - |
| CheY T112A | 4.8 ± 0.2 | 4.7 ± 0.6 | - | 17 ± 2 | - |
| CheY T112A A113P | 6.2 ± 0.2 | 0.85 ± 0.1 | - | 120 ± 20 | - |
a
Dephosphorylation kinetics were determined using the pH-jump method (n=3-5, with 12-20 replicate curves for each variant).
b
K1/2 values (concentration of donor required to phosphorylate 50% of the protein population; n=3 for each variant).
c
kdephos/K1/2 is equivalent to the bimolecular autophosphorylation rate, kphos/Ks.19
Mean values with standard deviations of the mean are provided.