Structure of the major peanut allergen Ara h 1 may protect IgE-binding epitopes from degradation.
In the past decade, there has been an increase in allergic reactions to peanut proteins, sometimes resulting in fatal anaphylaxis. The development of improved methods for diagnosis and treatment of peanut allergies requires a better understanding of the structure of the allergens. Ara h 1, a major peanut allergen belonging to the vicilin family of seed storage proteins, is recognized by serum IgE from >90% of peanut-allergic patients. In this communication, Ara h 1 was shown to form a highly stable homotrimer. Hydrophobic interactions were determined to be the main molecular force holding monomers together. A molecular model of the Ara h 1 trimer was constructed to view the stabilizing hydrophobic residues in the three dimensional structure. Hydrophobic amino acids that contribute to trimer formation are at the distal ends of the three dimensional structure where monomer-monomer contacts occur. Coincidentally, the majority of the IgE-binding epitopes are also located in this region, suggesting that they may be protected from digestion by the monomer-monomer contacts. On incubation of Ara h 1 with digestive enzymes, various protease-resistant fragments containing IgE-binding sites were identified. The highly stable nature of the Ara h 1 trimer, the presence of digestion resistant fragments, and the strategic location of the IgE-binding epitopes indicate that the quaternary structure of a protein may play a significant role in overall allergenicity.
Duke Scholars
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Related Subject Headings
- Structure-Activity Relationship
- Sodium Chloride
- Protein Conformation
- Plant Proteins
- Models, Molecular
- Membrane Proteins
- Immunology
- Immunoglobulin E
- Hydrolysis
- Hydrogen-Ion Concentration
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Structure-Activity Relationship
- Sodium Chloride
- Protein Conformation
- Plant Proteins
- Models, Molecular
- Membrane Proteins
- Immunology
- Immunoglobulin E
- Hydrolysis
- Hydrogen-Ion Concentration