Table 2.
Rate constants for dephosphorylation of CheY variants with imidazole and water
| Receiver domaina | kdephos,imida(M−1s−1) | kdephos,waterb ×10−5 (M−1s−1) | Relative sensitivity to imidazolec |
|---|---|---|---|
| CheYwt | 1.1 ± 0.1 | 75.0 ± 9.0d | 1,500 |
| CheYsmall | 1.2 ± 0.04 | 9.0 ± 0.6e | 14,000 |
| CheYlarge | 0.25 ± 0.005 | 3.3 ± 0.0d | 8,200 |
| CheYMPI | 4.3 ± 0.05 | 2.6 ± 0.3e | 170,000 |
a
Values are averages of second order rate constants from 2–3 measurements (completed at pH 10.3) ± SD and are determined by pH-jump fluorescence except CheYMPI was measured using 32P.
b
Calculated by dividing first order water-mediated dephosphorylation rate constants by the concentration of water (55.5 M).
c
Relative sensitivity to imidazole was calculated by dividing kdephos,imid by kdephos,water.
d
First order water-mediated dephosphorylation rate constants from 22.
e
First order water-mediated dephosphorylation rate constant determined using 32P as previously described in 22.