Table 1.
Association and Dissociation Rate Constants (ka, kd) and Apparent Affinity Constants (Kd) for Binding of Ligands 2–5 with Wild-Type TAF1 and TAF1 N1460D and N1583D Mutants as Measured by SPRa
| N1460D | ka(×106 M−1 s−1) | kd (×10−1 s−1) | Kd (nM) |
|---|---|---|---|
| 2 | 1.6 ± 0.1 | 1.7 ± 0.2 | 110 ± 10 |
| 3 | 1.1 ± 0.2 | 2.5 ± 0.1 | 230 ± 40 |
| 4 | 1.5 ± 0.1 | 3.6 ± 0.5 | 230 ± 40 |
| 5 | 1.8 ± 0.2 | 3.3 ± 0.1 | 190 ± 30 |
|
| |||
| N1583D | ka (×106 M−1 s−1) | kd (×10−1 s−1) | Kd (nM) |
|
| |||
| 2 | 0.8 ± 0.1 | 5 ± 1 | 600 ± 200 |
| 3 | 0.9 ± 0.4 | ≥10 ± ND | ≥1000 ± ND |
| 4 | 3.2 ± 0.7 | ≥10 ± ND | ≥300 ± ND |
| 5 | 0.2 ± 0.0 | 5 ± 2 | 3000 ± 1000 |
|
| |||
| WT | ka (×106 M−1 s−1) | kd (×10−1 s−1) | Kd (nM) |
|
| |||
| 2 | 2.0 ± 0.3 | 3.4 ± 0.4 | 170 ± 30 |
| 3 | 1.4 ± 0.4 | 1.9 ± 10.1 | 140 ± 40 |
| 4 | 2.8 ± 0.6 | 2.2 ± 0.2 | 80 ± 20 |
| 5 | 2.1 ± 0.4 | 4.6 ± 0.8 | 220 ± 50 |
a
All values represent the averages and standard (ka, kd) and propagated (Kd) errors from replicate measurements obtained at 25 °C. Interactions with dissociation rates (kd) ≥ 1 s−1 were rounded to 1 s−1, the limit of detection for the instrument, apparent affinities were calculated accordingly, and errors were not determined (ND).