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Binding of peanut allergen Ara h 2 with Vaccinium fruit polyphenols

Plundrich, Nathalie J., Cook, Bethany T., Maleki, Soheila J., Fourches, Denis, Lila, Mary Ann
Food chemistry 2019 v.284 pp. 287-295
Vaccinium, allergens, binding capacity, chemoinformatics, chlorogenic acid, circular dichroism spectroscopy, epitopes, fruits, immunoblotting, immunoglobulin E, myrtillin, peanuts, procyanidins, ultraviolet-visible spectroscopy
The potential for 42 different polyphenols found in Vaccinium fruits to bind to peanut allergen Ara h 2 and inhibit IgE binding epitopes was investigated using cheminformatics techniques. Out of 12 predicted binders, delphinidin-3-glucoside, cyanidin-3-glucoside, procyanidin C1, and chlorogenic acid were further evaluated in vitro. Circular dichroism, UV–Vis spectroscopy, and immunoblotting determined their capacity to (i) bind to Ara h 2, (ii) induce protein secondary structural changes, and (iii) inhibit IgE binding epitopes. UV–Vis spectroscopy clearly indicated that procyanidin C1 and chlorogenic acid interacted with Ara h 2, and circular dichroism results suggested that interactions with these polyphenols resulted in changes to Ara h 2 secondary structures. Immunoblotting showed that procyanidin C1 and chlorogenic acid bound to Ara h 2 significantly decreased the IgE binding capacity by 37% and 50%, respectively. These results suggest that certain polyphenols can inhibit IgE recognition of Ara h 2 by obstructing linear IgE epitopes.