Table 2.

Radius of P2X4R pore in the apo, holo, and holo plus allosteric modulators; (values are expressed as the mean ±standard deviation; values in Å).

P2X4R compartment	P2X4 apo	P2X4 holo	P2X4 holo IVM	P2X4 holo Zn(II)	P2X4 holo IVM Zn(II)
Upper vestibule	2.10 ± 0.19	1.83 ± 0.21	1.24 ± 0.28	1.34 ± 0.22	1.28 ± 0.20
Upper extracellular vestibule	5.95 ± 0.09	6.03 ± 0.30*	7.03 ± 0.26*	6.93 ± 0.15*	7.96 ± 0.01*
Extracellular vestibule	7.21 ± 0.23	9.27 ± 0.27*	8.45 ± 0.59	8.11 ± 0.58	8.40 ± 0.64
Intracellular vestibule	0.28 ± 0.07*	0.88 ± 0.1*	0.97 ± 0.28	0.86 ± 0.34	0.80 ± 0.28

Radius values were calculated following HOLE program analysis during the last 10 ns of the MD simulations lasting 30–40 ns (or 40–50 ns when allosteric modulators were present). The minimum radius of the upper vestibule was calculated, the maximum radius of the extracellular vestibule was also calculated as the minimum value of the intracellular vestibule (

^*p < 0.05 compared to P2X4R apo state).