title: Structural basis for pH gating of plant aquaporins.
abstract: Plants have evolved to cope with fluctuations in water supply by gating their water channels known as aquaporins. During flooding, a rapid drop of cytosolic pH due to anoxia leads to a simultaneous closure of the aquaporins in the plasma membrane. The closing mechanism has been suggested to involve a conserved histidine on cytosolic loop D. Here we report the crystal structure of a spinach aquaporin at low pH, revealing for the first time the structural basis for how this pH-sensitive histidine helps to keep the aquaporin in a closed state.
authors: Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.
authors: Anna
authors: A
authors: Frick
authors: Michael
authors: M
authors: Järvå
authors: Susanna
authors: S
authors: Törnroth-Horsefield
mesh_terms: D020346:Aquaporins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D018360:Crystallography, X-Ray; D003600:Cytosol / Q000737:chemistry / Q000378:metabolism; D006639:Histidine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D009154:Mutation; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D018724:Spinacia oleracea / Q000235:genetics / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
chemical_list: D020346:Aquaporins; D010940:Plant Proteins; D011994:Recombinant Proteins; D014867:Water; D006639:Histidine