3BRX

Crystal Structure of calcium-bound cotton annexin Gh1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.196 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

The crystal structure of calcium-bound annexin Gh1 from Gossypium hirsutum and its implications for membrane binding mechanisms of plant annexins.

Hu, N.-J.Yusof, A.M.Winter, A.Osman, A.Reeve, A.K.Hofmann, A.

(2008) J Biol Chem 283: 18314-18322

  • DOI: 10.1074/jbc.M801051200
  • Primary Citation of Related Structures:  
    3BRX

  • PubMed Abstract: 
  • Plant annexins show distinct differences in comparison with their animal orthologues. In particular, the endonexin sequence, which is responsible for coordination of calcium ions in type II binding sites, is only partially conserved in plant annexins. The crystal structure of calcium-bound cotton annexin Gh1 was solved at 2 ...

    Plant annexins show distinct differences in comparison with their animal orthologues. In particular, the endonexin sequence, which is responsible for coordination of calcium ions in type II binding sites, is only partially conserved in plant annexins. The crystal structure of calcium-bound cotton annexin Gh1 was solved at 2.5 A resolution and shows three metal ions coordinated in the first and fourth repeat in types II and III binding sites. Although the protein has no detectable affinity for calcium in solution, in the presence of phospholipid vesicles, we determined a stoichiometry of four calcium ions per protein molecule using isothermal titration calorimetry. Further analysis of the crystal structure showed that binding of a fourth calcium ion is structurally possible in the DE loop of the first repeat. Data from this study are in agreement with the canonical membrane binding of annexins, which is facilitated by the convex surface associating with the phospholipid bilayer by a calcium bridging mechanism. In annexin Gh1, this membrane-binding state is characterized by four calcium bridges in the I/IV module of the protein and by direct interactions of several surface-exposed basic and hydrophobic residues with the phospholipid membrane. Analysis of the protein fold stability revealed that the presence of calcium lowers the thermal stability of plant annexins. Furthermore, an additional unfolding step was detected at lower temperatures, which can be explained by the anchoring of the N-terminal domain to the C-terminal core by two conserved hydrogen bonds.


    Organizational Affiliation

    Institute of Structural and Molecular Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, UK.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
AnnexinA317Gossypium hirsutumMutation(s): 0 
Gene Names: AnnGh1
Membrane Entity: Yes 
UniProt
Find proteins for P93157 (Gossypium hirsutum)
Explore P93157 
Go to UniProtKB:  P93157
Protein Feature View
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.196 
  • Space Group: P 3 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 132.663α = 90
b = 132.663β = 90
c = 61.338γ = 120
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
MOLREPphasing
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

  • Deposited Date: 2007-12-21 
  • Released Date: 2008-05-06 
  • Deposition Author(s): Hu, N.-J., Hofmann, A.

Revision History  (Full details and data files)

  • Version 1.0: 2008-05-06
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance