Crystal structure of the spinach aquaporin SoPIP2;1 in a closed conformation

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.183 

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Structural mechanism of plant aquaporin gating

Tornroth-Horsefield, S.Wang, Y.Hedfalk, K.Johanson, U.Karlsson, M.Tajkhorshid, E.Neutze, R.Kjellbom, P.

(2006) Nature 439: 688-694

  • DOI: https://doi.org/10.1038/nature04316
  • Primary Citation of Related Structures:  
    1Z98, 2B5F

  • PubMed Abstract: 

    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 A resolution and in its open conformation at 3.9 A 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 A 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.

  • Organizational Affiliation

    Department of Chemistry and Bioscience, Chalmers University of Technology, P O Box 462, SE-40530 Göteborg, Sweden.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
B [auth M]
281Spinacia oleraceaMutation(s): 0 
Membrane Entity: Yes 
Find proteins for Q41372 (Spinacia oleracea)
Explore Q41372 
Go to UniProtKB:  Q41372
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ41372
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.183 
  • Space Group: I 4
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 90.097α = 90
b = 90.097β = 90
c = 189.181γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
CCP4data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-12-20
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance