3D Structure of Human Aquaporin-1 from Red Blood Cells
Look through the water channel.
View the side groups.
Look at the channel when the electron clouds are added to the view.
See the narrowest contriction of the channel. Notice the location of the two asparagines which disrupt the otherwise continuous column of hydrogen bonds which would allow protons to pass through aquaporin. The top half of this channel has been "slabbed" away so you cannot see the cysteine. To see the full channel, hold down the control key and "mouse down".