Crystal Structure of the Calcium-Binding Pollen Allergen Phl p 7 (Polcalcin) at 1.75 Angstroem

Experimental Data Snapshot

  • Resolution: 1.75 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.192 

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The cross-reactive calcium-binding pollen allergen, Phl p 7, reveals a novel dimer assembly

Verdino, P.Westritschnig, K.Valenta, R.Keller, W.

(2002) EMBO J 21: 5007-5016

  • DOI: https://doi.org/10.1093/emboj/cdf526
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The timothy grass pollen allergen Phl p 7 assembles most of the IgE epitopes of a novel family of 2 EF-hand calcium-binding proteins and therefore represents a diagnostic marker allergen and vaccine candidate for immunotherapy. Here we report the first three-dimensional structure of a representative of the 2 EF-hand allergen family, Phl p 7, in the calcium-bound form. The protein occurs as a novel dimer assembly with unique features: in contrast to well known EF-hand proteins such as calmodulin, parvalbumin or the S100 proteins, Phl p 7 adopts an extended conformation. Two protein monomers assemble in a head-to-tail arrangement with domain-swapped EF-hand pairing. The intertwined dimer adopts a barrel-like structure with an extended hydrophobic cavity providing a ligand-binding site. Calcium binding acts as a conformational switch between an open and a closed dimeric form of Phl p 7. These findings are interesting in the context of lipid- and calcium-dependent pollen tube growth. Furthermore, the structure of Phl p 7 allows for the rational development of vaccine strategies for treatment of sensitized allergic patients.

  • Organizational Affiliation

    Institute of Chemistry, Structural Biology Group, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz, Austria.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Polcalcin Phl p 7
A, B
78Phleum pratenseMutation(s): 0 
Gene Names: Phlpr
Find proteins for O82040 (Phleum pratense)
Explore O82040 
Go to UniProtKB:  O82040
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO82040
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.75 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.192 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 31.084α = 90
b = 56.205β = 90.23
c = 37.238γ = 90
Software Package:
Software NamePurpose
MAR345data collection
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-04-30
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-03-13
    Changes: Data collection, Database references, Derived calculations, Refinement description