Fig. 10From: A structural preview of aquaporin 8 via homology modeling of seven vertebrate isoformsThe selectivity filter of HsAQP8 remains AtTIP2;1-like during the MD simulation. The selectivity filter of each of the four monomers of the tetramer in the last frame of the 3Â ns simulation, the monomers are aligned to facilitate comparisons. The residues of the selectivity filter, H66 (H2P), F139 (LCP), I192 (H5P), G201 (LEP), R207 (HEP) as well as A137 in loop C are shown in stick representation together with the carbonyl oxygens of G200 and C202 lining the pore. R207 is stabilized in an AtTIP2;1-like position via hydrogen bonds (dashed lines) to H66 and to A137 of loop C via a water molecule, which has a variable position and is exchanged occasionally (Additional file 5: Movie S1). The orientation of the carbonyl of G201 (LEP) mainly points to the centre of the pore. The side pore remains more or less water filled during the simulation; the blue mesh marks the surface of water molecules in the last frameBack to article page