Table 2.
PixD | AppABLUFb | ||||||
---|---|---|---|---|---|---|---|
pKac | kH2O (s−1) | kD2O (s−1) | sied | kH2O (s−1) | kD2O (s−1) | sied | |
Wild-type | 9.9 | 0.038 ± 0.004 | 0.010 ± 0.0003 | 3.7 ± 0.1 | 0.00065 ± 0.00006 | 0.00013 ± 0.00001 | 5.0 ± 1 |
3-FY | 8.4 | 0.22 ± 0.012 | 0.023 ± 0.0008 | 9.5 ± 0.1 | 0.034 ± 0.002 | 0.0039 ± 0.0001 | 8.8 ± 0.7 |
2,3-F2Y | 7.8 | 0.27 ± 0.013 | 0.047 ± 0.0065 | 5.8 ± 0.1 | 0.22 ± 0.01 | 0.040 ± 0.001 | 5.5 ± 0.2 |
3,5-F2Y | 7.2 | 0.58 ± 0.06 | 0.058 ± 0.0036 | 9.9 ± 0.2 | 0.63 ± 0.02 | 0.11 ± 0.01 | 5.8 ± 0.3 |
2,3,5-F3Ye | 6.4 | ND | ND | ND | 2.6 ± 0.1 | 1.15 ± 0.03 | 2.2 ± 0.1 |
Recovery rate constants were obtained from the change in absorption spectra once irradiation at 455 nm had been terminated by fitting the data to a single exponential function. Errors are based on measurements made in triplicate or quadruplicate.
AppABLUF. Recovery data are for the BLUF domain of AppA and are taken from Gil et al.21
The pKa is that for the amino acid in solution.54
sie, solvent isotope effect.
ND, not detected. For 2,3,5-F3Y8 PixD no light state was detected.