Table 1.
Permeability of intracellular anions in wild-type and mutant CFTR Cl− channels
| Anion | WT | T338A | T338S | T338N | T338V | T339V |
|---|---|---|---|---|---|---|
| Thiocyanate | 2.63 ± 0.13 (6) | 5.85 ± 0.27 (4)* | 4.80 ± 0.19 (3)* | 8.72 ± 1.03 (4)* | 1.92 ± 0.35 (4)* | 3.28 ± 0.08 (4)* |
| Nitrate | 1.53 ± 0.04 (7) | 2.04 ± 0.08 (3)* | 1.82 ± 0.03 (4)* | 4.22 ± 0.22 (3)* | 6.84 ± 1.18 (7)* | 1.61 ± 0.02 (3) |
| Bromide | 1.23 ± 0.03 (5) | 1.74 ± 0.04 (3)* | 1.47 ± 0.07 (3)* | 1.66 ± 0.15 (3)* | 1.04 ± 0.09 (5) | 1.39 ± 0.06 (4)* |
| Chloride | 1.00 ± 0.01 (10) | 1.00 ± 0.02 (11) | 1.00 ± 0.02 (6) | 1.00 ± 0.03 (10) | 1.00 ± 0.04 (11) | 1.00 ± 0.06 (10) |
| Iodide | 0.84 ± 0.03 (5) | 2.09 ± 0.16 (5)* | 1.76 ± 0.09 (3)* | 1.03 ± 0.05 (3)* | 0.79 ± 0.11 (3) | 0.84 ± 0.02 (3) |
| Perchlorate | 0.25 ± 0.02 (6) | 1.35 ± 0.08 (3)* | 0.66 ± 0.06 (3)* | 0.41 ± 0.03 (3)* | 0.54 ± 0.00 (3)* | 0.24 ± 0.01 (4) |
| Benzoate | 0.069 ± 0.006 (6) | 0.17 ± 0.03 (4)* | 0.091 ± 0.019 (3) | 0.089 ± 0.015 (4) | 0.15 ± 0.02 (4)* | 0.097 ± 0.014 (4) |
| Hexafluorophosphate | < 0.019 (4) | 0.53 ± 0.01 (3)* | 0.31 ± 0.02 (3)* | 0.68 ± 0.02 (3)* | 0.39 ± 0.05 (3)* | 0.051 ± 0.010 (4)* |
| Fluoride | 0.11 ± 0.01 (7) | 0.12 ± 0.02 (4) | 0.095 ± 0.012 (4) | 0.11 ± 0.01 (4) | 0.093 ± 0.009 (3) | 0.17 ± 0.02 (4)* |
| Formate | 0.25 ± 0.01 (8) | 0.45 ± 0.04 (3)* | 0.43 ± 0.03 (3)* | 0.35 ± 0.04 (4)* | 0.22 ± 0.01 (3) | 0.28 ± 0.02 (3) |
| Acetate | 0.090 ± 0.004 (8) | 0.19 ± 0.01 (3)* | 0.18 ± 0.01 (3)* | 0.10 ± 0.02 (5) | 0.11 ± 0.02 (3) | 0.16 ± 0.01 (3)* |
| Propanoate | 0.14 ± 0.01 (3) | 0.18 ± 0.02 (4) | 0.098 ± 0.010 (4)* | 0.077 ± 0.013 (3)* | 0.13 ± 0.02 (3) | — |
| Pyruvate | 0.10 ± 0.01 (5) | 0.20 ± 0.01 (3)* | 0.13 ± 0.02 (3) | 0.075 ± 0.015 (3) | 0.17 ± 0.03 (3)* | — |
| Methane sulphonate | 0.077 ± 0.005 (5) | 0.14 ± 0.02 (4)* | 0.079 ± 0.014 (3) | 0.038 ± 0.004 (3)* | 0.088 ± 0.007 (3) | — |
| Glutamate | 0.096 ± 0.008 (4) | 0.082 ± 0.009 (3) | 0.080 ± 0.008 (3) | 0.060 ± 0.012 (5)* | 0.11 ± 0.01 (3) | — |
| Isethionate | 0.13 ± 0.01 (4) | 0.11 ± 0.01 (3) | 0.086 ± 0.012 (5)* | 0.043 ± 0.007 (3)* | 0.067 ± 0.005 (3)* | — |
| Gluconate | 0.068 ± 0.004 (36) | 0.10 ± 0.01 (3)* | 0.060 ± 0.004 (3) | 0.044 ± 0.004 (3) | 0.077 ± 0.009 (3) | 0.088 ± 0.021 (5) |
Relative permeabilities of different anions present in the intracellular solution under biionic conditions were calculated from macroscopic current reversal potentials (e. g. Figs 7 and 10) as described in Methods. Numbers in parentheses indicate the number of patches examined in each case.
*
Significantly different from the corresponding value in wild-type (P < 0.05, Student's two-tailed t test).