Table 2.

Voltage dependent gating and free energies of channel gating for I696X and W697X in the presence of 100 µM capsaicin

ChannelV0.5azgagmaxaPminbΔGo(I)cΔGo(V)dΔGoe
mVnSkcal/molkcal/molkcal/mol
TRPV1NANA124 ± 70.95 ± 0.01−2.67 ± 0.81NA−2.67 ± 0.81
I696A64 ± 50.55 ± 0.0660 ± 70.01 ± 0.062.67 ± 0.630.63 ± 0.153.30 ± 0.98
I696V70 ± 80.75 ± 0.0577 ± 150.21 ± 0.050.77 ± 0.121.33 ± 0.111.90 ± 0.31
I696L72 ± 70.76 ± 0.0986 ± 100.50 ± 0.070.05 ± 0.021.26 ± 0.251.30 ± 0.51
I696M48 ± 90.79 ± 0.0479 ± 90.15 ± 0.111.05 ± 0.050.57 ± 0.121.62 ± 0.51
I696H63 ± 60.79 ± 0.0770 ± 80.29 ± 0.040.52 ± 0.091.13 ± 0.201.65 ± 0.36
W697Y49 ± 90.85 ± 0.367 ± 160.51 ± 0.05−0.02 ± 0.010.98 ± 0.090.95 ± 0.17
W697H66 ± 80.87 ± 0.462 ± 120.67 ± 0.03−0.40 ± 0.061.30 ± 0.120.90 ± 0.14
W697V68 ± 70.89 ± 0.330 ± 60.57 ± 0.04−0.24 ± 0.031.30 ± 0.181.06 ± 0.19
W697D8 ± 110.72 ± 0.2133 ± 110.87 ± 0.02−1.05 ± 0.080.14 ± 0.06−0.91 ± 0.61
W697N57 ± 100.81 ± 0.3106 ± 130.81 ± 0.03−0.80 ± 0.071.11 ± 0.360.31 ± 0.31
  • 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. NA, not applicable.