TABLE 2.
Thermodynamic parameters for the interactions of GIRKCP mutants with spermine
| Mutant | Model | Stoichiometry per tetramer | Kd | ΔH | ΔS |
|---|---|---|---|---|---|
| μm | kcal/mol | kcal/mol K | |||
| Wild typea | Single sites | 1.54 ± 0.01 | 0.82 ± 0.09 | −1.93 ± 0.02 | 0.021 |
| E250N | N/A | ||||
| D260N | N/A | ||||
| D275N | Single sites | 1.74 ± 0.01 | 1.4 ± 0.1 | −2.09 ± 0.02 | 0.02 |
| E300N | N/A | ||||
| Q227A/Q261A | Single sites | 1.656 ± 0.003 | 0.29 ± 0.01 | −6.75 ± 0.02 | 0.0073 |
| F255A | Single sites | 1.194 ± 0.005 | 3.0 ± 0.2 | −0.845 ± 0.05 | 0.022 |
a Data for the wild type GIRKCP are presented for reference.