TABLE 2.
Pharmacological properties of mutant receptors
| Receptor | Kd (nM)a | No. of receptors per cella | EC50 (nM)b | Maximum α-factor induced activity (%)b |
|---|---|---|---|---|
| Wild type | 10.1 ± 0.7 | 11,000 ± 300 | 3.5 | 100 |
| S251L | 15.0 ± 6.1 | 810 ± 60 | 4.0 | 110 |
| C252L | 5.2 ± 1.7 | 2,400 ± 630 | 2.2 | 106 |
| Q253L | 0.4 ± 0.2 | 170 ± 8 | 0.5 | 110 |
| S254L | 1.9 ± 1.0 | 2,290 ± 168 | 2.0 | 93 |
| S254F | 0.9 ± 0.6 | 90 ± 13 | 1.2 | 80 |
| S259L | 2.8 ± 0.7 | 160 ± 3 | 4.0 | 20 |
a
Ligand-binding properties of yeast strain JKY78 carrying the indicated receptor genes on a plasmid were analyzed in equilibrium binding assays with 35S-labeled α-factor. The Kds and the numbers of receptors per cell were determined by Scatchard plot analysis.
b
EC50s and maximum α-factor-induced values were extrapolated from dose-response curves for FUS1-lacZ induction. Results are the averages of two to six independent assays, each done in duplicate (± standard deviations). The α-factor-induced activity of wild-type receptor cells was set to 100%.