ATP potencies, agonist-induced current responses and derived mutation-induced Gibbs free energy changes and interaction free energies of the wt and mutant P2X2 receptors
| rP2X2 | EC50 (95% CI) | EC50mut/EC50wt | nH | 1 mM ATP | Imaxmut/Imaxwt | n | ΔΔG | ΔΔGINT |
|---|---|---|---|---|---|---|---|---|
| µM | Imax, µA | |||||||
| wt | 11.4 (9.3–14.9) | — | 1.5 ± 0.4 | 53.9 ± 6.6 | — | 9 | 0 | |
| E167R | 6.3 (5.4–7.6) | 0.6 | 1.8 ± 0.2 | 35.9 ± 2.1 | 0.7 | 6 | −0.34 ± 0.05 | |
| R290E | 7192 (6393–8607) | 624 | 2.6 ± 0.3 | 0.1 ± 0.02 | 0.002 | 6 | 3.75 ± 0.06 | |
| E167R, R290E | 328 (288–371) | 29 | 2.6 ± 0.2 | 23.4 ± 1.7 | 0.4 | 6 | 1.95 ± 0.07 | −1.45 ± 0.03 |
| E167K | 17.5 (14.6–25.6) | 1.5 | 0.9 ± 0.4 | 24.6 ± 5.1 | 0.5 | 5 | 0.25 ± 0.02 | |
| R290D | 3538 (2815–4689) | 308 | 1.1 ± 0.1 | 0.08 ± 0.01 | 0.001 | 4 | 3.34 ± 0.01 | |
| E167K, R290D | 553 (491–658) | 48 | 2.5 ± 0.3 | 2.6 ± 0.4 | 0.05 | 4 | 2.25 ± 0.06 | −1.33 ± 0.08 |
| E167K, R290E | 889 (841–998) | 77 | 1.9 ± 0.3 | 4.1 ± 2.3 | 0.1 | 5 | 2.53 ± 0.09 | −1.46 ± 0.05 |
| E167R, R290D | 547 (509–652) | 48 | 2.4 ± 0.3 | 9.1 ± 3.5 | 0.2 | 4 | 2.25 ± 0.07 | −0.74 ± 0.03 |
| E167A | 11.4 (8.3–15.5) | 1 | 1.5 ± 0.3 | 51.0 ± 3.4 | 1.0 | 8 | −0.01 ± 0.04 | |
| R290A | 2663 (2054–3528) | 234 | 2.6 ± 0.3 | 2.4 ± 1.9 | 0.04 | 8 | 3.17 ± 0.01 | |
| E167A, R290A | 396 (299–525) | 35 | 2.4 ± 0.7 | 24.8 ± 3.7 | 0.5 | 7 | 2.06 ± 0.02 | −1.11 ± 0.03 |
| E167D | 24.7 (17.9–34.1 | 2 | 1.0 ± 0.2 | 17.3 ± 2.2 | 0.3 | 5 | 0.44 ± 0.04 | |
| R290K | 172 (137–209) | 15 | 1.8 ± 0.3 | 6.2 ± 1.9 | 0.1 | 5 | 1.58 ± 0.02 | |
| E167D, R290K | 182 (126–253) | 16 | 1.4 ± 0.5 | 14.1 ± 7.1 | 0.3 | 5 | 1.61 ± 0.06 | −0.41 ± 0.04 |
| D57R | 5.1 (3.7–7.1) | 0.5 | 1.3 ± 0.3 | 61.1 ± 5.5 | 1.1 | 10 | −0.47 ± 0.05 | |
| R275D | 377 (346–412) | 33 | 2.5 ± 0.3 | 12.3 ± 0.7 | 0.2 | 10 | 2.04 ± 0.09 | |
| D57R, R275D | 295 (277–314) | 26 | 2.0 ± 0.1 | 36.7 ± 1.3 | 0.7 | 11 | 1.89 ± 0.10 | 0.32 ± 0.07 |
| D57A | 12.8 (9.8–16.6) | 1.1 | 1.3 ± 0.2 | 54.9 ± 4.2 | 1.0 | 9 | 0.07 ± 0.02 | |
| R275A | 139 (117–164) | 12 | 2.0 ± 0.3 | 39.5 ± 3.6 | 0.7 | 10 | 1.45 ± 0.04 | |
| D57A, R275A | 91 (80–104) | 8 | 1.6 ± 0.1 | 84.6 ± 3.9 | 1.6 | 10 | 1.21 ± 0.06 | −0.31 ± 0.04 |
| rP2X2C9.348,430S | 10.2 (8.8–12.2) | — | 1.4 ± 0.1 | 55.7 ± 4.9 | — | 7 | ||
| E167Ca | 10.5 (7.5–14.1) | 1b | 1.5 ± 0.5 | 28.6 ± 4.8 | 0.5b | 7 | ||
| R290Ca | 729 (637–839) | 71b | 2.6 ± 0.4 | 3.0 ± 0.9 | 0.05b | 7 | ||
| E167C, R290Ca | 837 (784–901) | 82b | 2.6 ± 0.4 | 8.4 ± 2.4 | 0.2b | 8 |
ATP, adenosine-5’-triphosphate; ΔΔG, calculated Gibbs free energy changes of the mutant; ΔΔGINT, calculated interaction free energy (see Materials and Methods); Imax, mean current amplitude elicited by 1 mM ATP; n, number of independent measurements; nH, Hill coefficient.
↵a Generated using the rP2X2C9.348,430S receptor.
↵b Normalized to the rP2X2C9.348,430S receptor.