Fig. 2.

Architecture of human AQP10 and the glycerol-specific gate a Topology of hAQP10 monomer with six transmembrane helices (TM1-6) and five connecting stretches (loops A–E). Residues at the NPA-motifs, the classical ar/R selectivity filter and the cytoplasmic gate are indicated in green, purple and orange (throughout); hAQP10-specific residues in bold. The length of the crystallized form is also highlighted. b The hAQP10 tetramer from the cytoplasmic side, with chains A–C shown in gray and chain D in cyan tones. c Side-view of the primed-to-open monomer (chain D). A single glycerol (sticks) and four water (red spheres) molecules were identified. d The unusually wide ar/R selectivity region of hAQP10 (chain A, gray) compared to those in hAQP2 (blue, pdb-id 4NEF)²², AqpM (yellow, pdb-id 2F2B)¹⁶, GlpF (brown, pdb-id 1FX8)⁶⁸ and PfAQP (wheat, pdb-id 3C02)¹⁷. View from the non-cytoplasmic side. Glycerol molecules in the structures are shown as spheres in equivalent colors. e The channel profiles of selected aquaporins calculated using the software HOLE. hAQP10 chains A (gray) and D (cyan) are compared with increasing minimal diameter from left to right. The cytoplasmic gate and ar/R regions are marked in light orange and purple, respectively. f Close-view of the cytoplasmic and glycerol-specific gate. H80 forms an interaction network work with E27, F85, R94, V76 and S77