Table 1.
Summary of mutant phenotypes
| Residues corresponding to those analyzed in this study | ||||
| mP2X7 | hP2X7 | hP2X1 | rP2X2 | rP2X4 |
| R53K | R53 | T57 | D57 | E56 |
| R125K | R125 | G123 | H120A | A122 |
| R151K | R151 | K148 | H146 | R148 |
| R178K | R178 | R175 | N173 | Q175 |
| R206K | R206 | R202A | K200 | K203 |
| R230K | R230 | Q231 | K228A | R231 |
| R276K | R276H | H277 | R274 | R277 |
| R277K | R277 | G278 | R275 | R278K |
| R294K | R294 | R292A | R290A | R295 |
| R307K | R307Q | R305A | R304A | R309 |
| R316K | R316 | R314A | R313 | R318K |
| Other positively charged residues with altered ATP potency | ||||
| K64 | K64 | K68A | K69A | K67 |
| K66 | K66 | K70A | K71A | K69 |
| K193 | K193A | K190A | K188A | K190R |
| K311 | K311A | K309A | K308A | K313 |
Italics mutants with no or only small changes in ATP sensitivity, bold mutants with strongly reduced ATP potency, bold italics and underlined gain-of-function mutants, upright (without emphasis) residues that to our knowledge have not been tested by mutagenesis. References for: human P2X7 [53, 60, 74], human P2X1 [51], rat P2X2 [52, 64, 75], and rat P2X4 [65]