TABLE 2.
Binding properties of 125I-[Sar1,Ile8]AngII to AT1 receptor mutants
Cells expressing the indicated receptor were assayed for their binding properties as described under “Experimental Procedures.” Binding affinities (Kd) and maximal binding capacities (Bmax) were obtained in saturation binding experiments using 125I-[Sar1,Ile8]AngII. In dose displacement experiments, the tracer 125I-[Sar1,Ile8]AngII competed with increasing concentrations of AngII, and the IC50 values were converted to Kd values using the Cheng-Prusoff equation. All values are expressed as the means ± S.D. of values obtained in n independent experiments performed in duplicate.
| Receptor mutant |
Kd |
Bmax | n | |
|---|---|---|---|---|
| 125I-[Sar1,Ile8]AngII | AngII | |||
| nm | pmol/mg | |||
| AT1 | 1.9 ± 0.7 | 3.8 ± 0.3 | 1.5 ± 0.2 | 8 |
| N111G-AT1 | 2.7 ± 0.1 | 1.5 ± 0.4 | 0.9 ± 0.1 | 5 |
| N111W-AT1 | 7.7 ± 2.3 | 5.7 ± 1.5 | 0.7 ± 0.1 | 4 |
| N46G-AT1 | 6.4 ± 0.9 | 9.6 ± 2.8 | 1.1 ± 0.1 | 4 |
| N111G/N46G-AT1 | 6.9 ± 2.5 | 6.8 ± 1.5 | 0.7 ± 0.1 | 4 |
| D74N-AT1 | 4.1 ± 1.2 | 4.5 ± 1.3 | 0.4 ± 0.03 | 3 |
| N111G/D74N-AT1 | 4.4 ± 1.0 | 6.4 ± 1.1 | 0.2 ± 0.02 | 3 |
| F77A-AT1 | 4.3 ± 1.4 | 3.2 ± 1.1 | 1.7 ± 0.4 | 5 |
| N111W/F77A-AT1 | 3.1 ± 0.6 | 2.2 ± 0.8 | 1.5 ± 0.2 | 5 |