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Research Project: Defining, Measuring, and Mitigating Attributes that Adversely Impact the Quality and Marketability of Foods

Location: Healthy Processed Foods Research

Title: Identification and characterization of a new pecan [Cara illinoinensis (Wangenh.) K. Koch] allergen, Car i 2

Author
item Zhang, Yuzhu
item Lee, Boram - University Of Texas Southwestern Medical Center
item Du, Wen-xian
item Fan, Yuting - Jiangnan University
item Lyu, Shu-chen - Stanford University
item Nadeau, Kari - Stanford University
item Grauke, Larry - L J
item Zhang, Yan - Tianjin University Of Science And Technology
item Wang, Shuo - Tianjin University
item Mchugh, Tara

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2016
Publication Date: 4/29/2016
Citation: Zhang, Y., Lee, B., Du, W., Fan, Y., Lyu, S.C., Nadeau, K.C., Grauke, L.J., Zhang, Y., Wang, S., Mchugh, T.H. 2016. Identification and characterization of a new pecan [Cara illinoinensis (Wangenh.) K. Koch] allergen, Car i 2. Journal of Agricultural and Food Chemistry. 64:4146-4151.

Interpretive Summary: The Food and Drug Administration recognizes that 8 food groups cause the majority of food allergies in the US. Such allergen sources are required to be labeled when they are present in a food product by the Food Allergen Labeling and Consumer Protection Act of 2004. Failing to inform the consumer of an allergen source on a product label is one of the leading reasons for food recalls in recent years. Both allergenic patients and the food industry may become victims of foods containing unlabeled allergen sources. With an annual production valued at more than U.S. $670 million in 2011, pecan (Carya illinoinensis) is an important tree nut for the US agriculture. Information about pecan allergens is limited and pecan vicilin has not been studied. This study report the identification of a pecan allergen and the determination of its crystal structure. The reported result and the reagents generated may be used to understand the allergenicity of food allergens and enhance the marketability of the tree nut in the future.

Technical Abstract: The 7S and 11S seed storage globulins belong to the cupin protein superfamily and are major food allergens in many foods that are constitutors to the “big eight” groups of food allergen sources. Here, pecan vicilin was found to be a new food allergen. The vicilin protein consists a low-complexity region at its N-terminal and globular domain at the C-terminal that contains two cupin motifs and forms homotrimers. The crystal structure of recombinant pecan vicilin was determined in this study. The refined structure gave R/Rfree values of 0.21/0.26 for all data to 2.65 Å. There were two biological units in the crystallographic asymmetric unit. Pecan vicilin is also a copper protein. Further studies are needed to understand the nutritional value and the allergenicity relevance of the copper binding property of this seed storage protein in tree nuts and other plant seeds.