Table 1.
Measured affinity constants for ErbB3-binding ABD variants
| ABD variant | hErbB3 | mErbB3 | HSA | MSA | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| k a (M−1s−1) | k d (s−1) | K D (nM) | k a (M−1s−1) | k d (s−1) | K D (nM) | k a (M−1s−1) | k d (s−1) | K D (nM) | k a (M−1s−1) | k d (s−1) | K D (nM) | T m (°C) | |
| ABDErbB3-1 | 7.5 (± 0.2) × 105 | 5.6 (± 0.3) × 10−2 | 75 [4] | 9.1 (± 0.5) × 105 | 6.3 (± 0.3) × 10−2 | 69 [2] | 4.5 (± 1.9) × 105 | 5.7 (± 1.8) × 10−5 | 0.1 [6] | 2.6 (± 1.2) × 105 | 5.5 (± 0.3) × 10−4 | 2.1 [4] | ≥ 75 |
| ABDErbB3-2 | 1.0 (± 0.2) × 106 | 2.7 (± 0.3) × 10−2 | 26 [4] | 9.3 (± 0.3) × 105 | 3.1 (± 0.04) × 10−2 | 34 [2] | 6.6 (± 3.4) × 105 | 1.7 (± 0.4) × 10−4 | 0.3 [6] | 3.6 (± 1.9) × 105 | 1.2 (± 0.1) × 10−3 | 3.4 [4] | ≥ 80 |
| ABDErbB3-3 | 7.8 (± 0.6) × 105 | 7.6 (± 0.7) × 10−3 | 10 [4] | 8.3 (± 0.2) × 105 | 9.4 (± 0.06) × 10−3 | 11 [2] | 2.7 (± 0.4) × 105 | 1.1 (± 0.3) × 10−4 | 0.4 [6] | 1.8 (± 0.2) × 105 | 5.3 (± 0.3) × 10−4 | 3.0 [4] | ≥ 80 |
| ABDErbB3-13 | 6.1 (± 0.6) × 105 | 2.4 (± 0.1) × 10−2 | 39 [4] | 4.9 (± 0.01) × 105 | 1.8 (± 0.1) × 10−2 | 37 [2] | 2.2 (± 0.4) × 105 | 1.8 (± 0.6) × 10−4 | 0.8 [6] | 1.6 (± 0.4) × 105 | 1.4 (± 0.1) × 10−3 | 8.9 [4] | ≥ 75 |
| ABDErbB3-18 | 2.0 (± 0.2) × 105 | 1.8 (± 0.2) × 10−2 | 94 [4] | 1.8 (± 0.02) × 105 | 1.8 (± 0.1) × 10−2 | 97 [2] | 1.3 (± 0.3) × 105 | 1.1 (± 0.3) × 10−2 | 81 [6] | 5.6 (± 5.0) × 104 | 2.0 (± 1.3) × 10−2 | 367 [4] | ≥ 60 |
| ABDErbB3-20 | 2.7 (± 0.3) × 105 | 1.6 (± 0.1) × 10−2 | 60 [4] | 2.0 (± 0.1) × 105 | 1.7 (± 0.2) × 10−2 | 86 [2] | 1.6 (± 0.1) × 105 | 2.7 (± 0.3) × 10−4 | 1.7 [6] | 1.1 (± 0.04) × 105 | 1.2 (± 0.1) × 10−3 | 11 [4] | ≥ 60 |
| ABDErbB3-27 | 6.2 (± 1.4) × 105 | 7.4 (± 2.5) × 10−3 | 12 [4] | 2.4 (± 0.8) × 106 | 8.6 (± 4.6) × 10−3 | 4 [2] | 9.2 (± 0.6) × 104 | 1.7 (± 0.4) × 10−4 | 1.8 [3] | 7.1 (± 0.3) × 104 | 8.3 (± 0.4) × 10−4 | 12 [2] | ≥ 60 |
| ABD | – | – | – | – | – | – | 7.1 (± 1.2) × 104 | 5.8 (± 0.5) × 10−4 | 8.2 [9] | 6.7 (± 1.2) × 104 | 3.1 (± 0.2) × 10−3 | 46 [6] | ≥ 8 |
Affinities were determined by SPR analysis from multiple experiments. Constants are represented as mean values (± standard deviation) from the number of interactions indicated within brackets. K D values were calculated by k d/k a. Good reproducibility between replicate experiments of all interactions was achieved, as determined by the measured standard deviations and curve-fitting parameters (χ2 and residual plot, data not shown)