Web Release Date: June 25,
Detecting Potential IgE-Reactive Sites on Food Proteins Using a Sequence and Structure Database, SDAP-Food
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Sealy Center for Structural Biology, Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-1157 and Child Health Research Center, Department of Pediatrics, University of Texas Medical Branch, 310 University Boulevard, Galveston, Texas 77555-0366
Received for review March 5, 2003. Revised manuscript received May 13, 2003. Accepted May 14, 2003. This work was supported by grants from the John Sealy Memorial Endowment Fund (#2535-01), the U.S. Food and Drug Administration (FD-U-002249-1), and the Texas Higher Education Coordinating Board ATP(004952-0060-2001).
Abstract:
The high incidence of food allergies, including oral allergy syndrome, represent major considerations when introducing new crops and foods. A new structural database of allergenic proteins, SDAP-Food, http://fermi.utmb.edu/SDAP/, has been developed to aid in predicting the IgE-binding potential of novel food proteins and cross-reactivities among known allergens. The site is designed to facilitate the first steps of a decision tree approach to determine the allergenicity of a given protein, based on the sequence and structural similarity to known allergens and their IgE binding sites. Immunological tests can then be used to confirm the predictions. A hierarchical procedure for identifying potential allergens, using a physical property-based sequence similarity index, has been designed to identify regions that resemble known IgE binding sites. As an example, SDAP tools were used to find food allergen sequences similar to an IgE binding site of the Jun a 3 allergen from mountain cedar pollen. The SDAP sequence similarity search matched the Jun a 3 epitope to regions in several food allergens, including cherry (Pru av 2), apple (Mal d 2) and pepper (Cap a 1), which are, like Jun a 3, members of the plant pathogenesis-related (PR-5) protein family. Homology modeling, using our EXDIS/DIAMOD/FANTOM program suite, indicated a similar surface location and structure for the potential epitope region on all of these allergens. The quantitative approach presented here can be used as part of a screening process for potential allergenicity of recombinant food products.
Keywords: Allergen structure; pathogenesis related plant proteins; PR-5; Jun a 3; oral allergy syndrome; Pru av 2; Mal d 2; Cap a 1
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