Biochemical and Structural Analysis of the IgE Binding Sites on Ara h1, an Abundant and Highly Allergenic Peanut Protein

Allergy to peanut is a significant IgE-mediated health problem because of the high prevalence, potential severity, and chronicity of the reaction. Ara h1, an abundant peanut protein, is recognized by serum IgE from >90% of peanut-sensitive individuals. It has been shown to belong to the vicilin f...

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Bibliographic Details
Published in:The Journal of biological chemistry 1998-05, Vol.273 (22), p.13753-13759
Main Authors: Shin, David S., Compadre, Cesar M., Maleki, Soheila J., Kopper, Randall A., Sampson, Hugh, Huang, Shau K., Burks, A. Wesley, Bannon, Gary A.
Format: Article
Language:English
Subjects:
Adult
ALLERGENS
Allergens - chemistry
Allergens - metabolism
Amino Acid Sequence
AMINO ACID SEQUENCES
ANTIGENS
Arachis - immunology
Binding Sites
CHEMICAL COMPOSITION
Crystallography, X-Ray
EPITOPES
Epitopes - metabolism
GROUNDNUTS
Humans
Immunoglobulin E - metabolism
IMMUNOGLOBULINS
MANKIND
MOLECULAR CONFORMATION
Molecular Sequence Data
Placebos
PLANT PROTEINS
Protein Conformation
PROTEINS
Sequence Homology, Amino Acid
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Summary:Allergy to peanut is a significant IgE-mediated health problem because of the high prevalence, potential severity, and chronicity of the reaction. Ara h1, an abundant peanut protein, is recognized by serum IgE from >90% of peanut-sensitive individuals. It has been shown to belong to the vicilin family of seed storage proteins and to contain 23 linear IgE binding epitopes. In this communication, we have determined the critical amino acids within each of the IgE binding epitopes of Ara h1 that are important for immunoglobulin binding. Surprisingly, substitution of a single amino acid within each of the epitopes led to loss of IgE binding. In addition, hydrophobic residues appeared to be most critical for IgE binding. The position of each of the IgE binding epitopes on a homology-based molecular model of Ara h1 showed that they were clustered into two main regions, despite their more even distribution in the primary sequence. Finally, we have shown that Ara h1 forms a stable trimer by the use of a reproducible fluorescence assay. This information will be important in studies designed to reduce the risk of peanut-induced anaphylaxis by lowering the IgE binding capacity of the allergen.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.273.22.13753