Figure 3: a) Side view of the aquaporin-1 monomer (accession code 1FQY) cut such that the surface of the aqueous pore can clearly be seen in relation to the hydrophobic residues lining the aqueous pore (red) and the Asn-76 and Asn-192 residues (green) responsible for forming hydrogen bonds with passing water molecules can be seen.

b) End-on view of the surface of the aquaporin-1 monomer (accession code 1FQY) as seen from the extracellular surface in stereo. Asn-76 and Asn-192 are shown in green and the remaining members of each NPA motif are shown in blue (Pro-77, Ala-78, Pro-193 and Ala-184). The hydrophobic residues lining the aqueous pore (Phe-24, Ile-60, Leu-149 and Val-176) are shown in red. The constriction region of the pore is clearly defined by the interior surface of the depicted residues.