2II2

Crystal Structure of Alpha-11 Giardin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.1 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.195 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Apo and Calcium-bound Crystal Structures of Alpha-11 Giardin, an Unusual Annexin from Giardia lamblia

Pathuri, P.Nguyen, E.T.Svard, S.G.Luecke, H.

(2007) J.Mol.Biol. 368: 493-508

  • DOI: 10.1016/j.jmb.2007.02.016
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Alpha-11 giardin is a member of the multi-gene alpha-giardin family in the intestinal protozoan, Giardia lamblia. This gene family shares an ancestry with the annexin super family, whose common characteristic is calcium-dependent binding to membranes ...

    Alpha-11 giardin is a member of the multi-gene alpha-giardin family in the intestinal protozoan, Giardia lamblia. This gene family shares an ancestry with the annexin super family, whose common characteristic is calcium-dependent binding to membranes that contain acidic phospholipids. Several alpha giardins are highly expressed during parasite-induced diarrhea in humans. Despite being a member of a large family of proteins, little is known about the function and cellular localization of alpha-11 giardin, although giardins are often associated with the cytoskeleton. It has been shown that Giardia exhibits high levels of alpha-11 giardin mRNA transcript throughout its life cycle; however, constitutive over-expression of this protein is lethal to the parasite. Determining the three-dimensional structure of an alpha-giardin is essential to identifying functional domains shared in the alpha-giardin family. Here we report the crystal structures of the apo and Ca(2+)-bound forms of alpha-11 giardin, the first alpha giardin to be characterized structurally. Crystals of apo and Ca(2+)-bound alpha-11 giardin diffracted to 1.1 A and 2.93 A, respectively. The crystal structure of selenium-substituted apo alpha-11 giardin reveals a planar array of four tandem repeats of predominantly alpha-helical domains, reminiscent of previously determined annexin structures, making this the highest-resolution structure of an annexin to date. The apo alpha-11 giardin structure also reveals a hydrophobic core formed between repeats I/IV and II/III, a region typically hydrophilic in other annexins. Surprisingly, the Ca(2+)-bound structure contains only a single calcium ion, located in the DE loop of repeat I and coordinated differently from the two types of calcium sites observed in previous annexin structures. The apo and Ca(2+)-bound alpha-11 giardin structures assume overall similar conformations; however, Ca(2+)-bound alpha-11 giardin crystallized in a lower-symmetry space group with four molecules in the asymmetric unit. Vesicle-binding studies suggest that alpha-11 giardin, unlike most other annexins, does not bind to vesicles composed of acidic phospholipids in a calcium-dependent manner.


    Organizational Affiliation

    Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Alpha-11 giardin
A
310Giardia intestinalisMutation(s): 0 
Find proteins for Q4VPP2 (Giardia intestinalis)
Go to UniProtKB:  Q4VPP2
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.1 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.195 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 45.951α = 90.00
b = 60.954β = 90.00
c = 119.909γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
SOLVEphasing
d*TREKdata scaling
PDB_EXTRACTdata extraction
REFMACrefinement
ADSCdata collection
RESOLVEphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-04-17
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance