Structural determinants of water permeation through aquaporin-1
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Date
2000-10-05Author
Fujiyoshi, Yoshinori
Engel, Andreas
Heymann, J. Bernard
Agre, Peter
Walz, Thomas
Hirai, Teruhisa
Mitsuoka, Kaoru
Murata, Kazuyoshi
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Show full item recordAbstract
Human red cell AQP1 is the first functionally defined member of the aquaporin family of membrane water channels. Here we describe an atomic model of AQP1 at 3.8A resolution from electron crystallographic data. Multiple highly conserved amino-acid residues stabilize the novel fold of AQP1. The aqueous pathway is lined with conserved hydrophobic residues that permit rapid water transport, whereas the water selectivity is due to a constriction of the pore diameter to about 3 A over a span of one residue. The atomic model provides a possible molecular explanation to a longstanding puzzle in physiology-how membranes can be freely permeable to water but impermeable to protons.