Table 1.

Boltzmann parameters for V_m-dependence of WT and mutant RC×43 junctions

	A, mV−1	n, 20°C	V0, mV	Gjmax	Gjmin	Pomin
WT/WT (Vj = 0)*	0.043	1.09	−54	1.03	0.78	0.61
WT/WT (Vj = 80)*	0.031	0.79	−38	1.01	0.92	0.85
S257stop/S257stop (Vj = 0)*	0.041	1.06	−59	1.04	0.79	0.62
S257stop/S257stop (Vj = 80)*	0.037	0.94	−62	1.05	0.77	0.59
G242stop/G242stop	NE	NE	NE	NE	NE	NE
G242stop/WT†	0.046	1.16	−60	1.02	0.81	—
R243Q + D245Q/R243Q + D245Q*	NE	NE	NE	NE	NE	NE
R243Q/R243Q*	0.027	0.69	+11	1.04	0.91	0.83
D245Q/D245Q*	0.059	1.48	−64	1.04	0.41	0.64

^*G_jss/V_m relations of homotypic junctions were described by the square of a Boltzmann relation, based on a model of two independent V_m gates in series, one in each hemichannel, where each gate could be either open or completely closed. 

^† The G_jss/V_m relation of the heterotypic G242stop-WT junctions was fit by a single Boltzmann relation, assuming that only the gate of the WT hemichannels was contributing to the V_m sensitivity; the calculated parameters were close to those of the WT gate obtained by fitting a squared Boltzmann. NE, not estimated; the changes in G_jss were too small to allow accurate determination of the parameters. However, the smooth curves for these junctions in Figs. 1–3 were obtained by the same fitting procedures as for the more sensitive junctions.