Title
Identification, characterization, and initial epitope mapping of a pine nut allergen
Author
Yuzhu Zhang, Wen-Xian Du, Yuting Fan, Jiang Yi, Shu-Chen Lyu, Kari C. Nadeau, Tara H. McHugh
Year
2016
Journal
Food Research International
Abstract
The aims of this study were to predict, identify and characterize pine nut allergens. Korean pine (Pinus koraiensis) vicilin was predicted to be a pine nut allergen. Recombinant Korean pine vicilin was expressed in E. coli and purified. Natural Korean pine vicilin isolated from pine nuts (which displayed multiple bands in SDS-gels due to posttranslational digestion) and its full length recombinant counterpart were used test whether it is a food allergen. The recognition of the protein (and its fragments) by patient serum IgE was analyzed by Western blot. The study included fourteen patients diagnosed with clinical pine nut allergy. Twenty nine percent of the patient sera recognized both the natural and recombinant pine nut vicilin, indicating that Korean pine vicilin is a bona fide food allergen. The serum recognition patterns of the naturally occurring protein fragments suggested that some of linear IgE epitopes may be mapped to the fragment boundaries. The chemical and thermal stability of the recombinant protein was investigated. It underwent a thermal transition with a Tm = 76.6 °C. The transition was accompanied by an increase in the amplitude of the circular dichroism signal at 220 nm. Urea induced unfolding of the recombinant protein had a Cm of 4.6 M.
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, Thermal stability, Thermodynamics, Chemical stability, Biochemistry, Food science