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 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.

[1]  G. Reese,et al.  Why are some proteins allergenic? Implications for biotechnology. , 1996, Critical reviews in food science and nutrition.

[2]  J. Thornton,et al.  PROCHECK: a program to check the stereochemical quality of protein structures , 1993 .

[3]  J. Nordlee,et al.  Identification of a Brazil-nut allergen in transgenic soybeans. , 1996, The New England journal of medicine.

[4]  A. McPherson,et al.  The Three-Dimensional Structure of Canavalin from Jack Bean (Canavalia ensiformis) , 1993, Plant physiology.

[5]  M. Lawrence,et al.  Structure of phaseolin at 2.2 A resolution. Implications for a common vicilin/legumin structure and the genetic engineering of seed storage proteins. , 1994, Journal of molecular biology.

[6]  B. Martin,et al.  Identification of tropomyosin as the major shrimp allergen and characterization of its IgE-binding epitopes. , 1993, Journal of immunology.

[7]  A. Burks,et al.  Mechanisms of food allergy. , 1996, Annual review of nutrition.

[8]  J. Sebranek,et al.  Carrageenans and their use in meat products. , 1996, Critical reviews in food science and nutrition.

[9]  R. Helm,et al.  Recombinant peanut allergen Ara h I expression and IgE binding in patients with peanut hypersensitivity. , 1995, The Journal of clinical investigation.

[10]  M Karplus,et al.  Construction of a model for the three-dimensional structure of human renal renin. , 1985, Hypertension.

[11]  J. Devereux,et al.  A comprehensive set of sequence analysis programs for the VAX , 1984, Nucleic Acids Res..

[12]  R. Helm,et al.  Identification and mutational analysis of the immunodominant IgE binding epitopes of the major peanut allergen Ara h 2. , 1997, Archives of biochemistry and biophysics.

[13]  Roy L. Fuchs,et al.  Stability of food allergens to digestion in vitro , 1996, Nature Biotechnology.

[14]  B. J. Sutton,et al.  The human IgE network , 1993, Nature.

[15]  R. Helm,et al.  Mapping and mutational analysis of the IgE-binding epitopes on Ara h 1, a legume vicilin protein and a major allergen in peanut hypersensitivity. , 1997, European journal of biochemistry.

[16]  E. Isolauri,et al.  Evaluation of the gut mucosal barrier: evidence for increased antigen transfer in children with atopic eczema. , 1996, The Journal of allergy and clinical immunology.

[17]  S. Bock,et al.  Natural history of severe reactions to foods in young children. , 1985, The Journal of pediatrics.

[18]  H. Sampson,et al.  Fatal and near-fatal anaphylactic reactions to food in children and adolescents. , 1992, The New England journal of medicine.

[19]  M. Karplus,et al.  CHARMM: A program for macromolecular energy, minimization, and dynamics calculations , 1983 .

[20]  S. Bock,et al.  The natural history of peanut allergy. , 1989, The Journal of allergy and clinical immunology.

[21]  Bock Sa Prospective Appraisal of Complaints of Adverse Reactions to Foods in Children During the First 3 Years of Life , 1987 .

[22]  C A Royer,et al.  Numerical analysis of binding data: advantages, practical aspects, and implications. , 1992, Methods in enzymology.

[23]  G J Williams,et al.  The Protein Data Bank: a computer-based archival file for macromolecular structures. , 1977, Journal of molecular biology.

[24]  M. Shelton,et al.  A major continuous allergenic epitope of bovine β‐lactoglobulin recognized by human IgE binding , 1994, Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology.

[25]  A. Burks,et al.  Atopic dermatitis: clinical relevance of food hypersensitivity reactions. , 1988, The Journal of pediatrics.

[26]  S. Taylor,et al.  Identification of soybean allergens by immunoblotting with sera from soy-allergic adults. , 1990, International archives of allergy and applied immunology.

[27]  M. Schlaak,et al.  Reinvestigation of the major peanut allergen Ara h 1 on molecular level. , 1996, Monographs in allergy.

[28]  R. Helm,et al.  Identification of a major peanut allergen, Ara h I, in patients with atopic dermatitis and positive peanut challenges. , 1991, The Journal of allergy and clinical immunology.

[29]  H. Sampson,et al.  Cross-allergenicity in the legume botanical family in children with food hypersensitivity. II. Laboratory correlates. , 1989, The Journal of allergy and clinical immunology.

[30]  G. Fields,et al.  Solid phase peptide synthesis utilizing 9-fluorenylmethoxycarbonyl amino acids. , 2009, International journal of peptide and protein research.

[31]  T Ockhuizen,et al.  Prevalence of food allergy and intolerance in the adult Dutch population. , 1994, The Journal of allergy and clinical immunology.

[32]  A. Burks,et al.  Food allergies in children. , 1993, Current problems in pediatrics.

[33]  S. Kaminogawa Food allergy, oral tolerance and immunomodulation--their molecular and cellular mechanisms. , 1996, Bioscience, biotechnology, and biochemistry.