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

Shin, David; Compadre, César M.; Maleki, Soheila J.; Kopper, Randall A.; Sampson, Hugh A.; Huang, Shau Ku; Burks, A. Wesley; Bannon, Gary A.

doi:10.1074/jbc.273.22.13753

Cited by 237 publications

(209 citation statements)

References 36 publications

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“…5b. Interestingly, this IgE-binding epitope in the C-terminal domain of Gly m Bd 28 K occurs in a similar position to two epitopes of a peanut cupin allergen, Ara h 1 (epitope 14, D393-E402 and epitope 15, N409-K418) identified by Shin et al (1998).…”

Section: Sequence Analysis and Model Construction Of Gly M Bd 28 Kmentioning

confidence: 71%

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C-Terminal 23�kDa polypeptide of soybean Gly�m�Bd 28�K is a potential allergen

Xiang

Haas

Zeece

et al. 2004

Planta

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Gly m Bd 28 K is a major soybean (Glycine max Merr.) glycoprotein allergen. It was originally identified as a 28 kDa polypeptide in soybean seed flour. However, the full-length protein is encoded by an open reading frame (ORF) of 473 amino acids, and contains a 23 kDa C-terminal polypeptide of as yet unknown allergenic and structural characteristics. IgE-binding (allergenic potential) of the Gly m Bd 28 K protein including the 23 kDa C-terminal portion as well as shorter fragments derived from the full-length ORF were evaluated using sera from soy-sensitive adults. All of these sera contained IgE that efficiently recognized the C-terminal region. Epitope mapping demonstrated that a dominant linear C-terminal IgE binding epitope resides between residues S256 and A270. Alanine scanning of this dominant epitope indicated that five amino acids, Y260, D261, D262, K264 and D266, contribute most towards IgE-binding. A model based on the structure of the b subunit of soybean b-conglycinin revealed that Gly m Bd 28 K contains two cupin domains. The dominant epitope is on the edge of the first b-sheet of the C-terminal cupin domain and is present on a potentially solvent-accessible loop connecting the two cupin domains. Thus, the C-terminal 23 kDa polypeptide of Gly m Bd 28 K present in soy products is allergenic and apparently contains at least one immunodominant epitope near the edge of a cupin domain. This knowledge could be helpful in the future breeding of hypoallergenic soybeans.

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Section: Sequence Analysis and Model Construction Of Gly M Bd 28 Kmentioning

confidence: 71%

“…This type of structure may represent a potential allergenic region in several proteins. For example, two epitopes identified in the peanut allergen, Ara h 1 (Shin et al 1998) are also located in a partially solvent exposed edge of the predicted cupin domain of the Ara h 1 protein.…”

Section: Discussionmentioning

confidence: 99%

C-Terminal 23�kDa polypeptide of soybean Gly�m�Bd 28�K is a potential allergen

Xiang

Haas

Zeece

et al. 2004

Planta

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“…Ab binding sites are thought to be dependent on the native conformation of the allergen, and epitope identification using short overlapping peptides has been criticized in that this strategy does not produce meaningful results. However, this strategy has been used to identify major epitopes of peanut allergens (37)(38)(39), and studies of milk and peanut allergens suggested (40,41) associations between IgE Ab reactivities to linear peptides and severity of disease.…”

Section: Figurementioning

confidence: 99%

Reduced Allergenic Potency of VR9-1, a Mutant of the Major Shrimp Allergen Pen a 1 (Tropomyosin)

Reese

Viebranz

Leong-Kee

et al. 2005

The Journal of Immunology

107

101

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The major shrimp allergen, tropomyosin, is an excellent model allergen for studying the influence of mutations within the primary structure on the allergenic potency of an allergen; Pen a 1 allows systematic evaluation and comparison of Ab-binding epitopes, because amino acid sequences of both allergenic and nonallergenic tropomyosins are known. Individually recognized IgE Ab-binding epitopes, amino acid positions, and substitutions critical for IgE Ab binding were identified by combinatorial substitution analysis, and 12 positions deemed critical were mutated in the eight major epitopes. The mutant VR9-1 was characterized with regard to allergenic potency by mediator release assays using sera from shrimp-allergic subjects and sera from BALB/c, C57BL/6J, C3H/HeJ, and CBA/J mice sensitized with shrimp extract using alum, cholera toxin, and Bordetella pertussis, as adjuvants. The secondary structure of VR9-1 was not altered; however, the allergenic potency was reduced by 90–98% measuring allergen-specific mediator release from humanized rat basophilic leukemia (RBL) cells, RBL 30/25. Reduced mediator release of RBL-2H3 cells sensitized with sera from mice that were immunized with shrimp extract indicated that mice produced IgE Abs to Pen a 1 and to the same epitopes as humans did. In conclusion, data obtained by mapping sequential epitopes were used to generate a Pen a 1 mutant with significantly reduced allergenic potency. Epitopes that are relevant for human IgE Ab binding are also major binding sites for murine IgE Abs. These results indicate that the murine model might be used to optimize the Pen a 1 mutant for future therapeutic use.

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“…The Ara h 1 protein is known to form a homotrimer at relatively low concentrations, and this structure has been suggested to be important to the overall allergenicity of the molecule (14). To determine the stability and types of monomer interactions that mediate the formation of a homotrimer, fluorescence anisotropy measurements were performed in the presence of increasing salt concentrations (0 -1.8 M NaCl).…”

Section: Ara H 1 Trimers Are Stable At High Concentrations Of Naclmentioning

confidence: 99%

“…However, a molecular model of the tertiary structure of the Ara h 1 protein shows that the IgE-binding sites were clustered into two main regions. In addition, Ara h 1 forms homotrimers, a physical characteristic that may be important in establishing it as an allergen (14).…”

mentioning

confidence: 99%

Structure of the Major Peanut Allergen Ara h 1 May Protect IgE-Binding Epitopes from Degradation

Maleki

Kopper²,

Shin³

et al. 2000

The Journal of Immunology

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240

210

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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.

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

Cited by 237 publications

References 36 publications

C-Terminal 23�kDa polypeptide of soybean Gly�m�Bd 28�K is a potential allergen

C-Terminal 23�kDa polypeptide of soybean Gly�m�Bd 28�K is a potential allergen

Reduced Allergenic Potency of VR9-1, a Mutant of the Major Shrimp Allergen Pen a 1 (Tropomyosin)

Structure of the Major Peanut Allergen Ara h 1 May Protect IgE-Binding Epitopes from Degradation

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