Table 3. Functional properties of cysteine mutant receptors.
Mutants | EC50 (μM) | n H | Imax (pA/picofarad) | n | ΔΔG (Kcal.mol-1) | ΔΔGINT (Kcal.mol-1) |
rP2X2R-WT | 4.1 ± 0.9 | 0.7 ± 0.1 | 49.1 ± 10.6 | 20 | 0 | |
rP2X2R-T | 3.7 ± 0.6 | 1.3 ± 0.3 | 51.7 ± 9.3 | 30 | 0 | |
V48C | 5.8 ± 0.5 | 1.3 ± 0.1 | 66.8 ± 9.1 | 5 | 0.24 ± 0.03 | |
I328C | 3.9 ± 0.6 | 1.5 ± 0.3 | 73.1 ± 11.4 | 5 | 0.09 ± 0.02 | |
H33C | 2.3 ± 0.5 | 1.3 ± 0.3 | 35.8 ± 8.3 | 5 | -0.29 ± 0.13 | |
S345C | 6.3 ± 0.9 | 1.2 ± 0.1 | 40.5 ± 7.6 | 5 | 0.30 ± 0.08 | |
V48A | 3.2 ± 0.6 | 1.6 ± 0.1 | 25.4 ± 2.1 | 7 | -0.1 ± 0.11 | |
I328A | 0.4 ± 0.1 | 1.7 ± 0.2 | 31.7 ± 6.1 | 6 | -1.31 ± 0.15 | |
H33A | 4.2 ± 0.6 | 1.6 ± 0.3 | 41.7 ± 8.3 | 6 | 0.08 ± 0.07 | |
S345A | 12.1 ± 0.7 | 1.3 ± 0.2 | 27.5 ± 5.8 | 7 | 0.69 ± 0.03 | |
F44C | 0.81 ± 0.1 | 0.9 ± 0.3 | 39.2 ± 2.1 | 4 | -0.89 ± 0.07 | |
A337C | 6.2 ± 0.5 | 1.2 ± 0.4 | 30.1 ± 4.1 | 4 | 0.30 ± 0.05 | |
V48C/I328C | 17.8 ± 2.0 | 0.9 ± 0.2 | 12.8 ± 1.8 | 28 | 0.91 ± 0.07 | 0.59 ± 0.03 |
H33C/S345C | 7.3 ± 1.1 | 1.3 ± 0.2 | 95.9 ± 12.3 | 10 | 0.36 ± 0.10 | 0.33 ± 0.10 |
V48A/I328A | 5.4 ± 0.4 | 1.3 ± 0.3 | 42.0 ± 6.5 | 5 | 0.22 ± 0.04 | 1.60 ± 0.04 |
H33A/S345A | 35.7 ± 0.5 | 1.4 ± 0.1 | 33.1 ± 4.1 | 7 | 1.32 ± 0.01 | 0.66 ± 0.01 |
F44C/A337C | 1.5 ± 0.5 | 1.5 ± 0.2 | 41.4 ± 1.5 | 4 | -0.52 ± 0.19 | 0.10 ± 0.18 |
rP2X2R-T after DTT | 3.9 ± 0.5 | 0.7 ± 0.2 | 67.3 ± 11.2 | 10 | 0 | |
V48C after DTT | 5.5 ± 0.5 | 1.3 ± 0.1 | 67.1 ± 8.7 | 5 | 0.23 ± 0.05 | |
I328C after DTT | 4.0 ± 0.6 | 1.6 ± 0.3 | 70.2 ± 14.3 | 5 | 0.1 ± 0.03 | |
H33C after DTT | 3.1 ± 0.3 | 1.3 ± 0.3 | 35.8 ± 8.3 | 5 | -0.11 ± 0.06 | |
S345C after DTT | 6.5 ± 0.7 | 1.2 ± 0.1 | 40.5 ± 7.6 | 5 | 0.32 ± 0.13 | |
V48C/I328C after DTT | 3.6 ± 0.4 | 1.1 ± 0.2 | 21.1 ± 4.6 | 15 | 0.27 ± 0.19 | -0.31 ± 0.07 |
V48C/I328C after H2O2 | 17.9 ± 1.9 | 0.7 ± 0.1 | 11.9 ± 1.7 | 6 | 0.92 ± 0.06 | 0.59 ± 0.03 |
H33C/S345C after DTT | 3.19 ± 0.3 | 1.4 ± 0.2 | 97.2 ± 11.9 | 10 | -0.09 ± 0.05 | -0.12 ± 0.05 |
H33C/S345Cafter H2O2 | 6.4 ± 0.5 | 1.4 ± 0.3 | 63.8 ± 7.8 | 5 | 0.32 ± 0.05 | 0.28 ± 0.05 |
The data represent the mean ± S.E.M. of the numbers of cells studied (n).