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Structural mechanism of plant aquaporin gating

Författare:
Publiceringsår: 2006
Språk: Engelska
Sidor: 688-694
Publikation/Tidskrift/Serie: NATURE
Volym: 439
Nummer: 7077
Dokumenttyp: Artikel
Förlag: NATURE PUBLISHING GROUP

Sammanfattning

Plants counteract fluctuations in water supply by regulating all aquaporins in the cell plasma membrane. Channel closure results either from the dephosphorylation of two conserved serine residues under conditions of drought stress, or from the protonation of a conserved histidine residue following a drop in cytoplasmic pH due to anoxia during flooding. Here we report the X-ray structure of the spinach plasma membrane aquaporin SoPIP2; 1 in its closed conformation at 2.1 angstrom resolution and in its open conformation at 3.9 angstrom resolution, and molecular dynamics simulations of the initial events governing gating. In the closed conformation loop D caps the channel from the cytoplasm and thereby occludes the pore. In the open conformation loop D is displaced up to 16 angstrom and this movement opens a hydrophobic gate blocking the channel entrance from the cytoplasm. These results reveal a molecular gating mechanism which appears conserved throughout all plant plasma membrane aquaporins.

Disputation

Nyckelord

  • Earth and Environmental Sciences

Övriga

Published
Yes
  • ISSN: 0028-0836

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