Table 2.

Correlation analysis of gating pore residues

Position		WW	KD	HH	MF	SA	Vol
V236	V1/2	−0.04	0.02	−0.11	0.26	−0.05	−0.16
	TA	−0.04	0.52	0.44	0.16	0.05	0.23
	TD	0.30	0.62*	0.59*	0.34	0.21	0.38
I237	V1/2	−0.86***	−0.89***	−0.89***	−0.83***	−0.15	−0.29
	TA	−0.62*	−0.22	−0.45	−0.26	0.14	0.38
	TD	0.13	0.48	0.33	0.28	−0.28	0.12
S240	V1/2	0.68*	0.18	0.27	0.51	0.90***	0.85***
	TA	0.24	−0.09	0.03	−0.06	0.54*	0.45
	TD	0.64	0.44	0.58	0.53	0.44	0.23
I241	V1/2	−0.23	−0.44	−0.40	−0.33	−0.26	−0.38
	TA	0.05	0.22	0.29	0.06	−0.44	−0.58*
	TD	−0.31	0.26	0.08	−0.10	−0.51	−0.54*
F244	V1/2	−0.79***	−0.01	−0.23	−0.46	−0.78**	−0.64*
	TA	0.16	−0.20	−0.11	0.08	0.26	0.21
	TD	0.08	0.13	0.11	0.28	0.29	0.39
C286	V1/2	0.13	−0.43	−0.42	0.00	0.52	0.24
	TA	0.38	0.63*	0.53	0.45	0.39	0.55
	TD	0.12	0.66*	0.43	0.53	−0.11	0.11
I287	V1/2	0.55*	−0.04	0.28	0.32	0.44	0.36
	TA	0.39	0.41	0.44	0.48	0.25	0.05
	TD	0.50	0.59*	0.61*	0.71**	0.54*	0.59*
F290	V2	−0.79***	−0.11	−0.35	−0.47	−0.65*	−0.57*
	TA	−0.07	−0.32	−0.42	−0.20	0.31	0.35
	TD	0.84***	−0.19	0.03	0.24	0.78***	0.69**
A319	V1/2	0.24	−0.46	−0.41	−0.10	0.20	0.13
	TA	−0.05	0.24	0.18	0.31	−0.28	−0.18
	TD	0.21	0.54	0.57	0.27	−0.10	0.01
I320	V1/2	0.03	−0.50	−0.35	−0.33	−0.09	−0.26
	TA	−0.24	−0.36	−0.24	−0.48	−0.61	−0.78*
	TD	−0.01	0.12	0.18	0.06	−0.35	−0.30

The table indicates the Pearson pairwise correlation coefficient between each measured gating parameter (T^A, T^D, and V_1/2) and each tested side-chain physicochemical parameter: HH, KD, WW, MF, vdW surface area (SA), and volume (Vol), for each gating pore residue. The MF and HH scales were inverted such that more positive values indicate more hydrophobic residues in all hydrophobicity scales. The F290 mutants display bisigmoid Q–V curves; hence the second component V₂ is used instead of V_1/2 (Results and Discussion). The number of asterisks indicates the statistical significance as follows: *0.01 ≤ P < 0.05, **0.001 ≤ P < 0.01, and ***P < 0.001.