Effect of transglutaminase-catalyzed glycosylation on the allergenicity of tropomyosin in the Perna viridis food matrix

Abstract

Food allergy is one of the hot issues in the field of food safety, and there have been a lot of concerns on how to reduce the allergenicity of food allergens. Food processing can change the allergenicity of allergens in the food matrix. In this study, ten IgE linear epitopes of the major allergen tropomyosin (TM) in Perna viridis were identified by bioinformatics prediction and serological experiments. The transglutaminase-catalyzed glycosylation modification sites glutamine, lysine and arginine were highly represented in the IgE linear epitopes of TM. The Perna viridis food matrix was treated with transglutaminase-catalyzed glycosylation. This reaction changed the secondary structure of protein in the food matrix, increased the content of β-sheets and decreased the content of β-turns. The intensity of intrinsic fluorescence and surface hydrophobicity were reduced. The IgE-binding activity of TM in the food matrix was reduced by modifying seven amino acid residues on six IgE linear epitopes. Transglutaminase-catalyzed glycosylation products decreased allergic symptoms in allergic mice, reduced the proportion of CD4⁺IL-4⁺ Th2 cells, and increased the proportion of CD4⁺IFN-γ⁺ Th1 cells and Treg cells. Mouse serum levels of IgE and IgG1 antibodies in the food matrix and TM were reduced. Therefore, this study provided a theoretical basis for the development of hypoallergenic Perna viridis products.