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.
Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Aquaporins / chemistry
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Aquaporins / genetics
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Aquaporins / metabolism*
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Binding Sites / genetics
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Biological Transport
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Cell Membrane / metabolism
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Crystallography, X-Ray
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Cytosol / chemistry
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Cytosol / metabolism
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Histidine / chemistry
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Histidine / genetics
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Histidine / metabolism
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Hydrogen-Ion Concentration
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Models, Molecular
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Mutation
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Plant Proteins / chemistry
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Plant Proteins / genetics
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Plant Proteins / metabolism*
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Protein Conformation
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Protein Structure, Secondary
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
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Spinacia oleracea / genetics
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Spinacia oleracea / metabolism*
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Water / metabolism*
Substances
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Aquaporins
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Plant Proteins
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Recombinant Proteins
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Water
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Histidine