1j4n | pdb_00001j4n
Crystal Structure of the AQP1 water channel
Structural highlights
Function[AQP1_BOVIN] Forms a water-specific channel that provides the plasma membranes of red cells and kidney proximal tubules with high permeability to water, thereby permitting water to move in the direction of an osmotic gradient. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWater channels facilitate the rapid transport of water across cell membranes in response to osmotic gradients. These channels are believed to be involved in many physiological processes that include renal water conservation, neuro-homeostasis, digestion, regulation of body temperature and reproduction. Members of the water channel superfamily have been found in a range of cell types from bacteria to human. In mammals, there are currently 10 families of water channels, referred to as aquaporins (AQP): AQP0-AQP9. Here we report the structure of the aquaporin 1 (AQP1) water channel to 2.2 A resolution. The channel consists of three topological elements, an extracellular and a cytoplasmic vestibule connected by an extended narrow pore or selectivity filter. Within the selectivity filter, four bound waters are localized along three hydrophilic nodes, which punctuate an otherwise extremely hydrophobic pore segment. This unusual combination of a long hydrophobic pore and a minimal number of solute binding sites facilitates rapid water transport. Residues of the constriction region, in particular histidine 182, which is conserved among all known water-specific channels, are critical in establishing water specificity. Our analysis of the AQP1 pore also indicates that the transport of protons through this channel is highly energetically unfavourable. Structural basis of water-specific transport through the AQP1 water channel.,Sui H, Han BG, Lee JK, Walian P, Jap BK Nature. 2001 Dec 20-27;414(6866):872-8. PMID:11780053[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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