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United States Department of Agriculture

Agricultural Research Service

Research Project: Reduction of Allergenicity through Food Processing

Location: Healthy Processed Foods Research

Title: Crystal structure of peanut (Arachis hypogaea) allergen Ara h 5

Authors
item Wang, Yang -
item Fu, Tong-Jen -
item Howard, Andrew -
item Kothary, Mahendra -
item McHugh, Tara
item Zhang, Yuzhu

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 25, 2013
Publication Date: January 25, 2013
Citation: Wang, Y., Fu, T., Howard, A., Kothary, M.H., Mchugh, T.H., Zhang, Y. 2013. Crystal structure of peanut (Arachis hypogaea) allergen Ara h 5. Journal of Agricultural and Food Chemistry. 61:1573-1578.

Interpretive Summary: Ara h 5 is a peanut allergen which belongs to the profilin protein family. Profilins are known to be involved in numerous types of pollen and food allergies. Structural characterization of allergens will allow a better understanding of the allergenicity of food allergens and their cross-reactivities. This study reported the first crystallization and structural characterization of food allergen in the profilin family. Determined at a very high resolution (1.1 angstrom), the structure of Ara h 5 is more similar to birch allergen Bet v 2 than to latex allergen Hev b 8 although its relationship to Hev b 8 is closer than to Bet v 2 based on sequence alignments. These results indicated that predictions of IgE epitopes based on homology models, which often built from sequence alignments, needs to be interpreted with caution.

Technical Abstract: Profilins from numerous species are known to be allergens, including food allergens, such as peanut (Arachis hypogaea) allergen Ara h 5, and pollen allergens, such as birch allergen Bet v 2. Patients with pollen allergy can also cross-react to peanut. Structural characterization of allergens will allow a better understanding of the allergenicity of food allergens and their cross-reactivities. The three-dimensional structures of most known food allergens remain to be elucidated. Here, we report the first crystallographic study of a food allergen in the profilin family. The structure of peanut allergen Ara h 5 was determined and the resolution of the final refined structure was 1.1 angstrom. Structure alignment revealed that Ara h 5 is more similar to Bet v 2 than to Hev b 8 although sequence alignment suggested that Ara h 5 is more closely related to Hev b 8 than to Bet v 2, indicating that homology model-based prediction of IgE epitopes needs to be interpreted with caution.

Last Modified: 4/16/2014