TABLE 3.

Water flux observed in the four simulations

	Water count				Flux (#/ns)
	M1	M2	M3	M4	Mean	SD
sim1	−13.5	−14.5	−15	−17.5	−3.8	0.4
sim2	−9.5	−6	−1	−12.5	−1.8	1.2
sim3	11.5	8.5	5	8	2.1	0.7
sim4	11.5	9	10.5	7	2.4	0.5

To obtain the net water transfer through a channel, a plane normal to its axis is defined, and when a water molecule crosses the plane, a count of +1 or −1 is accumulated, depending on its crossing direction. Two such planes were defined in the central part of the channel, and the average of their net counts is listed as the water count of the channel. The mean and standard deviation (SD) of the flux were calculated from the water counts of the four monomers (M1–M4) during 4 ns.