Crystal structure of Fel d 1- the major cat allergen

Experimental Data Snapshot

  • Resolution: 1.85 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.203 

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The crystal structure of the major cat allergen Fel d 1, a member of the secretoglobin family.

Kaiser, L.Gronlund, H.Sandalova, T.Ljunggren, H.G.van Hage-Hamsten, M.Achour, A.Schneider, G.

(2003) J Biol Chem 278: 37730-37735

  • DOI: https://doi.org/10.1074/jbc.M304740200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The domestic cat (Felis domesticus) is one of the most important causes of allergic asthma worldwide. The dominating cat allergen, Fel d 1, is composed of two heterodimers. Recently, it has been shown that recombinant Fel d 1, consisting of chain 2 and chain 1 fused together without additional linker, has immunological properties indistinguishable from the natural heterodimeric protein. Herein, we report the crystal structure of recombinant monomeric Fel d 1 at 1.85-A resolution, determined by multi-wavelength anomalous diffraction using selenomethionine substituted protein. Fel d 1 is an all-helical protein and consists of eight helices. The two halves of the recombinant Fel d 1 molecule, corresponding to the wild-type Fel d 1 chains, are very similar in three-dimensional structure, despite the lack of significant sequence identity. The structure of the Fel d 1 presents a striking similarity to that of uteroglobin, a steroid-inducible cytokine-like molecule with anti-inflammatory and immunomodulatory properties. An internal, asymmetric cavity is formed in the Fel d 1 that could bind an endogenous ligand. The distribution of residues lining this cavity suggests that such a ligand must be amphipathic. The structure of Fel d 1 displays the localization of three previously defined Fel d 1 IgE epitopes on the surface of the protein. The three-dimensional structure provides a framework for rational design of hypoallergenic mutants aimed for treatment of cat allergy.

  • Organizational Affiliation

    Department of Medicine, Unit of Clinical Immunology and Allergy, Karolinska Institutet and Hospital L2:04, S-171 76 Stockholm, Sweden.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Major allergen I polypeptide, fused chain 2, chain 1
A, B
170Felis catusMutation(s): 0 
Gene Names: CH2CH1
Membrane Entity: Yes 
Find proteins for P30438 (Felis catus)
Explore P30438 
Go to UniProtKB:  P30438
Find proteins for P30440 (Felis catus)
Explore P30440 
Go to UniProtKB:  P30440
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupsP30438P30440
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.85 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.203 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 43.29α = 90
b = 51.539β = 95.27
c = 67.725γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
CCP4data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-10-14
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-08-02
    Changes: Data collection, Refinement description, Source and taxonomy
  • Version 1.4: 2019-07-03
    Changes: Advisory, Author supporting evidence, Data collection, Derived calculations