Table 1.

Voltage dependent gating and free energies of channel gating for I696X and W697X in the presence of 1 µM capsaicin

ChannelV0.5azgagmaxaPminbΔGo(I)cΔGo(V)dΔGoe
mVnSkcal/molkcal/molkcal/mol
TRPV1−22 ± 50.62 ± 0.08124 ± 70.32 ± 0.010.20 ± 0.08−0.29 ± 0.060.23 ± 0.12
I696A100 ± 100.68 ± 0.0960 ± 70.003 ± 0.063.26 ± 0.381.56 ± 0.194.83 ± 0.79
I696V81 ± 60.62 ± 0.0777 ± 150.08 ± 0.051.43 ± 0.131.16 ± 0.102.59 ± 0.29
I696L78 ± 80.64 ± 0.0986 ± 100.08 ± 0.071.42 ± 0.071.16 ± 0.182.28 ± 0.38
I696M87 ± 70.74 ± 0.0779 ± 90.01 ± 0.112.69 ± 0.291.48 ± 0.154.20 ± 0.48
I696H65 ± 90.65 ± 0.0670 ± 80.08 ± 0.041.43 ± 0.180.97 ± 0.132.40 ± 0.39
W697Y68 ± 70.90 ± 0.267 ± 160.40 ± 0.040.21 ± 0.051.34 ± 0.081.55 ± 0.11
W697H69 ± 90.87 ± 0.362 ± 120.25 ± 0.030.64 ± 0.041.36 ± 0.112.00 ± 0.18
W697V68 ± 60.88 ± 0.330 ± 60.23 ± 0.050.70 ± 0.051.33 ± 0.122.03 ± 0.20
W697D68 ± 40.71 ± 0.1133 ± 110.09 ± 0.021.34 ± 0.101.25 ± 0.142.59 ± 0.44
W697N73 ± 80.75 ± 0.2106 ± 130.03 ± 0.012.06 ± 0.071.26 ± 0.133.32 ± 0.34
  • a The parameter values obtained from the best fit of the g-V curves to a Boltzmann distribution (Figs. 5 B and 6 A). Free energies were estimated assuming a two-state gating model.

  • b Pmin denotes the normalized conductance at hyperpolarized potentials (gmin/gmax), where gmin has been obtained for the best fit of the g-V curve to a Boltzmann distribution.

  • c The free energy of the voltage-independent component, obtained as –RT ln[(Pmin/(1 − Pmin)].

  • d The free energy of the voltage-dependent component, obtained as zgFV0.5.

  • e The total free energy of the gating process, obtained as ΔGo(I) + ΔGo(V).

  • Data are given as mean ± SEM, with n ≥ 5.