Table 2.
Comparison of natural PadCs and synthetic fusions with respect to kinetics of substrate conversion
| Constructs | Initial rates at 200 μm GTPa |
Fold activation | |
|---|---|---|---|
| Dark | Light | ||
| (μmol product) min−1 (μmol enzyme2)−1 | |||
| IsPadC | 1.7 ± 0.2 | 32 ± 3 | 19-fold |
| IsPadC+7KE | 0.13 ± 0.04 | 0.08 ± 0.01 | |
| IsN/PG/Yt/Y/CCTsD | 0.55 ± 0.04 | 9.0 ± 0.2 | 16-fold |
| IsN/PG/Yt/Y/CCΔ515–521TsD | 0.02 ± 0.01 | 17.0 ± 0.1 | 800-fold |
| IsN/PG/Yt/Y/CC501–507TsCC505–518/D | 0.02 ± 0.01 | 4.6 ± 0.8 | 200-fold |
| IsN/PG/Yt/YTsCC/D | 0.25 ± 0.02 | 1.09 ± 0.07 | 4-fold |
| IsN/PGTsYt/Y/CC/D | 1.9 ± 0.5 | 8.11 ± 0.01 | 4-fold |
| TsNIsPG/Yt/Y/CCTsD | 1.04 ± 0.03 | 17.2 ± 0.6 | 16-fold |
| TsNIsPGTsYt/Y/CC/D | 0.6 ± 0.04 | 1.0 ± 0.1 | 2-fold |
| TsNIsPGTsYtIsY/CC/D | 0.07 ± 0.01 | 55 ± 1 | 800-fold |
| TsN/PG/Yt/YIsCC/Db | 10.9 ± 0.1 | 9 ± 1 | |
| TsN/PG/Yt/Y/CCIsD | 15 ± 1 | 34 ± 1 | 2-fold |
| TsPadC | 8.0 ± 0.7 | 52 ± 3 | 7-fold |
a Comparison of product formation between the various constructs was performed for initial reaction rates at 200 μm GTP and after normalization to the dimeric protein concentration. Initial rates are quantified from experimental triplicates for three time points, and the sample standard deviation of individual points contributed to the error estimation of the linear fit that is used to calculate the initial rate of product formation. The S.E. of the estimate from the linear regression is used as an error indicator.
b Dark-state kinetics of this construct have been measured from the monomer fraction featuring only the Pr state.