Table 1. Binding Affinities of SFK SH3 Domains for the VSL12 Peptide as Measured by SPR.
| Protein | ka (M−1s−1±SE) | kd (s−1±SE) | Kinetic KD (M) | Kinetic χ2 | Steady-State KD (M) | Steady State χ2 |
| Src SH3a | 1.21×105±0.03×105 | 4.14×10−1±0.08 ×10−1 | 3.42×10−6 | 0.570 | 4.00×10−6 | 0.260 |
| Fyn SH3b | 1.06×106±0.03×106 | 3.72×10−1±0.10×10−1 | 3.51×10−7 | 1.890 | 3.70×10−7 | 1.070 |
| Hck SH3c | 7.88×104±0.36×104 | 2.17×10−1±0.04×10−1 | 2.76×10−6 | 1.360 | 2.99×10−6 | 0.390 |
| Lyn SH3b | 2.12×105±0.10×105 | 1.37×10−1±0.04×10−1 | 6.47×10−7 | 1.850 | 5.62×10−7 | 0.225 |
| SH2d | ND | ND | - | - | - | - |
| Kinased | ND | ND | - | - | - | - |
Analyses were performed with biotinylated VSL12 peptide bound to a streptavidin biosensor chip as described under Materials and Methods. Each protein was flowed past the chip surface over the concentration ranges indicated in the footnotes. Duplicate runs were performed for each concentration. A control cycle of buffer only was subtracted from all concentrations of reference-subtracted curves. To calculate the kinetic KD, interaction data were curve-fit using a 1∶1 Langmuir model, with binding constants and chi-squared values calculated using the BIAevaluation software. To calculate the steady state KD, the analyte response at equilibrium was plotted against the analyte concentration, and resulting curves were fit with the steady state model in the BIAevaluation software.
31.25, 62.5, 125, 250, 500, 1000 nM.
31.25, 62.5, 125, 250 nM.
31.25, 62.5, 125, 250, 500 nM.
SH2 domains tested: Src, Hck, Fyn and Lyn; kinase domains tested, Src and Hck. ND, binding not detected with 1 µM protein input.