Expression of Jug r 1, the 2S albumin allergen from walnut ( Juglans regia), as a correctly folded and functional recombinant protein

• Published in: Peptides (New York, N.Y. : 1980) N.Y. : 1980), 2009-07, Vol.30 (7), p.1213-1221
• Main Authors: Sordet, Camille, Culerrier, Raphaël, Granier, Claude, Rancé, Fabienne, Didier, Alain, Barre, Annick, Rougé, Pierre
• Format: Article
• Language: English
• Subjects: 2S Albumins, Plant - chemistry; 2S Albumins, Plant - genetics; 2S Albumins, Plant - metabolism; Animals; Antigens, Plant - chemistry; Antigens, Plant - genetics; Antigens, Plant - metabolism; Binding Sites; Biological and medical sciences; Cell Line, Tumor; Epitopes - chemistry; Epitopes - genetics; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Fundamental and applied biological sciences. Psychology; IgE-binding epitopes; Immunoglobulin E - metabolism; Jug r 1; Juglans - genetics; Juglans - metabolism; Juglans regia; Pepsin cleavage; Protein Folding; Protein Structure, Secondary; Protein Structure, Tertiary; Rats; Recombinant allergen; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Vertebrates: endocrinology
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/j.peptides.2009.03.007

Jug r 1, the 2S albumin allergen from walnut, was isolated from ripe nuts as a native allergen and expressed in Escherichia coli using the Gateway ® technology as a recombinant allergen. The recombinant Jug r 1 (15 kDa) differs from the native allergen by the absence of cleavage of the polypeptide chain in two covalently associated light (3.5 kDa) and heavy (8 kDa) chains. Recombinant rJug r 1 adopts the canonical α-helical fold of plant 2S albumins as checked on CD spectra. Four IgE-binding epitopic stretches were identified along the amino acid sequence of Jug r 1 and localized on the molecular surface of the modeled allergen. Both native and recombinant allergens exhibit similar IgE-binding activity and similarly trigger the degranulation of a FcɛRI-expressing rat basophilic leukaemia cell line previously treated by IgE-containing sera. Native Jug r 1 resists to heat denaturation and to the proteolytic attack of trypsin and chymotrypsin but is readily hydrolyzed in the presence of pepsin at acidic pH after 1 h of incubation at 37 °C in vitro. Recombinant Jug r 1 could be used for a component-resolved diagnosis of food-allergy.