TABLE 3.
Ki values for single-Cys CTP variants
Ki values (mm) ± S.E. were calculated from the inhibition data depicted in Tables 1 and 2 as described under “Experimental Procedures.” NSI denotes no significant inhibition was observed with a given CTP mutant-anion pair, defined as ≤3% inhibition depicted in Tables 1 and 2. α-KG is α-ketoglutarate; PEP is phosphoenolpyruvate.
| CTP variant | Isocitrate | α-KG | Malate | Succinate | Malonate | PEP | ADP | Phosphate | Pyruvate | Glutamate |
|---|---|---|---|---|---|---|---|---|---|---|
| Cys-less | 6.4 ± 0.1 | 38.3 ± 3.8 | 50.2 ± 6.3 | 43.6 ± 2.4 | 38.3 ± 11.5 | 18.6 ± 0.5 | 46.7 ± 13.7 | 96.7 ± 21.5 | NSI | NSI |
| K83C | 24.1 ± 3.4 | 16.1 ± 0.3 | 14.8 ± 1.4 | 19.0 ± 1.0 | 30.7 ± 2.1 | 16.1 ± 1.3 | 27.2 ± 0.6 | 27.2 ± 4.1 | NSI | 72.4 ± 26.1 |
| R87C | 14.8 ± 1.2 | 15.5 ± 2.5 | 15.5 ± 1.0 | 21.5 ± 2.8 | 28.4 ± 2.5 | 13.0 ± 0.6 | 32.1 ± 3.7 | 43.1 ± 8.4 | NSI | 85.9 ± 27.3 |
| G119C | 18.1 ± 1.0 | 33.2 ± 6.3 | 51.1 ± 9.6 | 80.5 ± 14.0 | 51.1 ± 6.4 | 23.1 ± 0.5 | 51.1 ± 3.2 | 58.9 ± 12.2 | 376.8 ± 376.8 | 102.5 ± 10.8 |
| R189C | 8.2 ± 0.2 | 6.6 ± 0.1 | 6.6 ± 0.3 | 5.8 ± 0.1 | 11.0 ± 0.6 | 32.3 ± 0.8 | 57.3 ± 7.9 | 33.7 ± 3.3 | 21.6 ± 1.7 | 60.1 ± 10.7 |
| K37C | 231.5 ± 33.1 | NSI | 273.0 ± 45.5 | NSI | 231.5 ± 132.3 | 231.5 ± 66.1 | 127.8 ± 53.2 | 176.2 ± 78.3 | NSI | NSI |
| R181C | 136.4 ± 18.2 | 46.7 ± 1.4 | 39.3 ± 4.1 | 41.0 ± 7.8 | 44.7 ± 3.8 | 65.1 ± 12.1 | 194.7 ± 53.1 | 46.7 ± 6.9 | 377.1 ± 439.9 | NSI |
| K239C | 148.8 ± 21.3 | 581.2 ± 871.8 | 162.1 ± 37.4 | NSI | 195.9 ± 89.1 | 103.2 ± 16.3 | 379.4 ± 505.9 | 118.2 ± 34.8 | 148.8 ± 42.5 | NSI |
| R276C | 22.6 ± 2.2 | 32.5 ± 2.4 | 28.8 ± 1.3 | 28.8 ± 0.6 | 43.8 ± 2.5 | 10.6 ± 1.1 | 19.3 ± 0.7 | 43.8 ± 3.8 | 447.7 ± 358.2 | 36.9 ± 4.7 |
| R279C | 26.8 ± 2.9 | 13.4 ± 1.9 | 22.0 ± 1.3 | 25.8 ± 0.5 | 17.9 ± 1.9 | 13.4 ± 1.7 | 30.3 ± 5.5 | 20.3 ± 2.6 | 315.9 ± 135.4 | 50.5 ± 3.2 |