Table III

Parameters of Deactivation Kinetics

Constructτ−50*vshiftk*τmin*ve-fold change§n*
msmVmsmV
IFMQ30.9 ± 0.1n.a.‖2.1 ± 0.20.2 ± 0.111.75
1R2Q1.0 ± 0.4 −0.92.5 ± 0.21760.2 ± 0.1 9.95
1R2K0.7 ± 0.23.21.8 ± 0.11760.1 ± 0.113.64
1K4Q0.3 ± 0.1176     12.31.3 ± 0.11760.1 ± 0.119.65
1K4R0.8 ± 0.32.22.1 ± 0.30.2 ± 0.111.67
2R2Q0.8 ± 0.11.72.0 ± 0.20.1 ± 0.112.78
2R2K0.6 ± 0.11764.72.3 ± 0.20.2 ± 0.111.04
2K4Q0.6 ± 0.2176 5.71.9 ± 0.20.2 ± 0.113.06
2K4R0.9 ± 0.20.32.0 ± 0.30.2 ± 0.112.74
3R2Q1.2 ± 0.4 −3.31.9 ± 0.10.2 ± 0.113.24
3R2K1.1 ± 0.4 −2.42.3 ± 0.30.1 ± 0.110.84
3R4Q2.4 ± 0.3176−11.21.6 ± 0.31760.2 ± 0.215.53
3R4K0.3 ± 0.1176     12.01.7 ± 0.21760.2 ± 0.115.04
4R2Q0.7 ± 0.11763.82.0 ± 0.10.2 ± 0.112.55
4R2K1.1 ± 0.5 −2.01.9 ± 0.30.2 ± 0.112.94
4R4Q1.0 ± 0.2 −1.11.9 ± 0.10.2 ± 0.112.85
4R4K0.6 ± 0.21765.31.8 ± 0.21760.2 ± 0.113.77
1K4Q:2K4Q0.3 ± 0.1176     14.21.2 ± 0.11760.2 ± 0.121.69
3R4Q:4R4Q3.0 ± 0.5176−14.11.3 ± 0.21760.0 ± 0.219.06
  • * τ−50, τmin, and k were determined by least-squares fits of the data (n = number of separate determinations) to a voltage-dependent single exponential as described in materials and methods.  

  • vshift is the shift in voltage for the mutant τd compared with the IFMQ3 τd, calculated using the IFMQ3 value for k.  

  • § ve-fold change is the voltage required for an e-fold change in τd for the condition when τmin << τd.  

  • n.a., not applicable.  

  • 176  Values significantly different from IFMQ3, with a probability <0.05 resulting from random variation (based on Student's unpaired t test).