Molecular modelling of the major peanut allergen Ara h 1 and other homotrimeric allergens of the cupin superfamily: a structural basis for their IgE-binding cross-reactivity.
Three-dimensional models of the major vicilin allergens from peanut (Ara h 1), lentil (Len c 1) and pea (Pis s 1), were built by homology-based modelling from the X-ray coordinates of the structurally closely related soybean beta-conglycinin. All the allergen monomers exhibit the typical cupin motif made of two modules related by a pseudo-dyad axis. Each module consists of a beta-barrel core domain associated to a loop domain which mainly contains alpha-helices. The three cupin motifs are assumed to be arranged in a homotrimeric structure similar to that observed in beta-conglycinin, phaseolin or canavalin. Most of the sequential B-cell epitopes characterized on the C-terminus of the Ara h 1 allergen are well conserved in both Len c 1 and Pis s 1 allergens. They occupy very comparable areas on the molecular surface of the allergens and exhibit a similar three-dimensional conformation. This antigenic community readily accounts for the IgE-binding cross-reactivity commonly observed between the vicilin allergens from edible legume seeds. The clinical implication of this cross-reactivity is addressed for a definite diagnosis of legume seed allergy.
Barre
Annick
A
Surfaces Cellulaires et Signalisation chez les Végétaux, UMR-CNRS 5546, Pôle de Biotechnologie végétale, 24, chemin de Borde Rouge, 31326 Castanet-Tolosan, France.
Borges
Jean-Philippe
JP
Rougé
Pierre
P
D000485:Allergens / Q000737:chemistry*; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D003429:Cross Reactions; D005512:Food Hypersensitivity / Q000175:diagnosis; D005916:Globulins / Q000737:chemistry; D006023:Glycoproteins / Q000737:chemistry*; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism*; D008565:Membrane Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry; D017434:Protein Structure, Tertiary; D055314:Seed Storage Proteins; D016415:Sequence Alignment; D030262:Soybean Proteins / Q000737:chemistry
D000485:Allergens; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; D005916:Globulins; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; D007073:Immunoglobulin E; C015575:vicilin protein, plant