Table 2. ITC and SPR data showing thermodynamic and kinetic parameters of protein-protein interactions involved in UPEC536 mediated CDI system.
ITC data were fit using one-site binding model for CdiA-CT(M)/CdiI and two site binding model for rest of the complexes. The parameters for the second binding site are shown in the parentheses.
| Protein samples | ITC | SPR | |||||
|---|---|---|---|---|---|---|---|
| N | ΔH (cal/mol) | ΔS (cal/mol/K) | KD (nM) | KD (nM) | kon (M–1s–1) | koff (s–1) | |
| CdiA-CT(M) + CdiI | 0.993 | -2.9 × 104 ± 115.9 | -60.3 | 26.4 ± 2.1 | 12.8 ± 1 | 5.1 × 106 | 6.5 × 10−2 |
| CdiA-CT(M) + CysK | 0.494 | -5618 ± 167.9 (-2.02 × 104 ± 145.9) | 14.0 (-34.5) | 79.3 ± 8.9 (89.2 ± 10.1) | 32 ± 4 | 6.2 × 103 | 1.4 × 10−4 |
| CysK/CdiA-CT(M) + CdiI | 1.892 | -2.67 × 104 ± 1.28 × 103 (-2.42 × 104 ± 1.18 × 103) | -46.6 (-38.9) | 1.3 ± 0.5 (1.1 ± 0.3) | 0.3 ± 0.08 | 1.5 × 106 | 5.0 × 10−4 |
| CdiA-CT(M)/ CdiI + CysK | 0.512 | -1.1 × 104 ± 157.9 (-2.67 × 104 ± 267.9) | -0.9 (-31.1) | 12.0 ± 1.9 (13.4 ± 2.3) | |||