XB-IMG-121623
Xenbase Image ID: 121623
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Figure 2. Effects of S4D4 point mutations on kinetics and on voltage dependence of macroscopic Na+ currents. (A) Comparison of normalized single current traces of WT (solid line) and mutant (dotted line) channels, elicited by a depolarizing pulse to −5 mV from a −100-mV holding potential. The settling times of the corresponding capacitance transients are almost identical (data not shown). (B) Semilogarithmic plots of single (mutants) or double (WT inactivation) exponential fits, as indicated, from representative current traces elicited by depolarizing pulses to −20, −5, and 20 mV; holding potential −100 mV. Single fits accord to the following equation. INa(t) = A * (1 − exp (−t/τm))3*exp(−t/τh) + P * (1 − exp(−t/τm))3. WT: (τm/τh (fast)/τh (slow) in ms) 0.48/0.70/4.20 (−20 mV); 0.28/0.70/5.10 (−5 mV); 0.17/0.51/3.10 (20 mV); R4H: (τm/τh in ms) 0.41/2.90 (−20 mV); 0.31/2.50 (−5 mV); 0.23/1.80 (20 mV); R4/5H: (τm/τh in ms) 0.45/4.30 (−20 mV); 0.24/3.80 (−5 mV); 0.15/2.90 (20 mV); R5H: (τm/τh in ms) 0.45/5.50 (−20 mV); 0.25/4.90 (−5 mV); 0.16/3.10 (20 mV). Image published in: Kühn FJ and Greeff NG (1999) © 1999 The Rockefeller University Press. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |