Homology modelling and conformational analysis of IgE-binding epitopes of Ara h 3 and other legumin allergens with a cupin fold from tree nuts.

Linear IgE-binding epitopes identified in legumin allergens of peanut (Ara h 3) and other allergenic tree nuts (Jug r 4 of walnut, Cor a 9 of hazelnut, Ana o 2 cashew nut) were mapped on three-dimensional models of the proteins built up by homology modelling. A conformational analysis revealed that consensual surface-exposed IgE-binding epitopes exhibited some structural homology susceptible to account for the IgE-binding cross-reactivity observed among peanut and tree nut allergens. This structurally related cross-reactivity seems irrespective of the botanical origin of the allergens and thus demands that persons allergic to peanut avoid other three nuts to prevent possible allergic reactions. IgE-binding epitopes similar to those found in 11S globulin allergens do not apparently occur in other vicilin allergens with the cupin fold from peanut (Ara h 1) or tree nuts (Jug r 2 of walnut, Cor a 1 of hazel nut, Ana o 3 of cashew nut).