Skip to Main Content
TABLE I

Summary of Voltage and pH Dependence of Mutants

Mutant
V1/2 (mV) at pH 7.3
Slope (mV per pH unit)
z
Slope*z/58 mV
C212S −92 ± 16 46 ± 2 0.89 ± 0.11 0.71 
S123A −105 ± 20 44 ± 12 0.78 ± 0.15 0.60 
P126G −117 ± 4 45 ± 7 0.93 ± 0.14 0.72 
E127Q −93 ± 13 66 ± 7 1.09 ± 0.10 1.25 
K129A ND ND ND ND 
R133Q −93.3 ± 8 63.8 ± 7 1.0 ± 0.16 1.09 
K149L −45 ± 8 106 ± 4 0.69 ± 0.14 1.28 
E166A ND ND ND ND 
F214L 49 ± 7 43 ± 1 1.28 ± 0.04 0.95 
S224A −105 ± 16 50 ± 6 0.96 ± 0.26 0.84 
E226D −59 ± 11 48 ± 17 1.0 ± 0.2 0.83 
E226Q 144 ± 34 155 ± 12 0.40 ± 0.06 1.0 
V227E −101 ± 15 67 ± 10 0.83 ± 0.11 0.97 
C229S −108 ± 4 60.5 ± 5 0.84 ± 0.06 0.88 
R305E −103 ± 4 56 ± 14 0.86 ± 0.09 0.84 
R312Q −93 ± 9 40 ± 7 1.0 ± 0.16 0.69 
C415S −99 ± 5 47.7 ± 4 1.0 ± 0.07 0.84 
A417F −133 ± 16 78 ± 11 0.81 ± 0.1 1.09 
F418A ND ND ND ND 
F418C −64 ± 8 79.5 ± 2 0.93 ± 0.14 1.28 
V419M −111 ± 15 73.6 ± 5 0.82 ± 0.1 1.04 
P420G −135 ± 11 99 ± 13 0.50 ± 0.05 0.86 
H472K ND ND ND ND 
Y512A −80 ± 12 51 ± 5 0.81 ± 0.13 0.71 
K519Q −103 ± 17 64 ± 7 0.96 ± 0.18 1.07 
Mutant
V1/2 (mV) at pH 7.3
Slope (mV per pH unit)
z
Slope*z/58 mV
C212S −92 ± 16 46 ± 2 0.89 ± 0.11 0.71 
S123A −105 ± 20 44 ± 12 0.78 ± 0.15 0.60 
P126G −117 ± 4 45 ± 7 0.93 ± 0.14 0.72 
E127Q −93 ± 13 66 ± 7 1.09 ± 0.10 1.25 
K129A ND ND ND ND 
R133Q −93.3 ± 8 63.8 ± 7 1.0 ± 0.16 1.09 
K149L −45 ± 8 106 ± 4 0.69 ± 0.14 1.28 
E166A ND ND ND ND 
F214L 49 ± 7 43 ± 1 1.28 ± 0.04 0.95 
S224A −105 ± 16 50 ± 6 0.96 ± 0.26 0.84 
E226D −59 ± 11 48 ± 17 1.0 ± 0.2 0.83 
E226Q 144 ± 34 155 ± 12 0.40 ± 0.06 1.0 
V227E −101 ± 15 67 ± 10 0.83 ± 0.11 0.97 
C229S −108 ± 4 60.5 ± 5 0.84 ± 0.06 0.88 
R305E −103 ± 4 56 ± 14 0.86 ± 0.09 0.84 
R312Q −93 ± 9 40 ± 7 1.0 ± 0.16 0.69 
C415S −99 ± 5 47.7 ± 4 1.0 ± 0.07 0.84 
A417F −133 ± 16 78 ± 11 0.81 ± 0.1 1.09 
F418A ND ND ND ND 
F418C −64 ± 8 79.5 ± 2 0.93 ± 0.14 1.28 
V419M −111 ± 15 73.6 ± 5 0.82 ± 0.1 1.04 
P420G −135 ± 11 99 ± 13 0.50 ± 0.05 0.86 
H472K ND ND ND ND 
Y512A −80 ± 12 51 ± 5 0.81 ± 0.13 0.71 
K519Q −103 ± 17 64 ± 7 0.96 ± 0.18 1.07 

The voltage of half-maximal activation (at pH 7.3) and the apparent gating valence (z) are shown in columns 2 and 4, respectively. The slope of the V1/2 − pH curve was obtained from a linear fit to all data points, except for mutant F214L for which the slope was obtained from V1/2 values at pH 9.0 and 10. The last column displays the product of the slope (column 3) and the apparent gating valence (column 4), divided by 58 mV. Theoretical considerations (Boccaccio et al., 1998) indicate that this product takes into account the unspecific interdependence of these two parameters. For each mutant at least five patches were used for the averages. Error bars indicate SD; ND (not determined) indicates mutants for which the Boltzmann analysis was not possible.

Close Modal

or Create an Account

Close Modal
Close Modal