Identification, Expression, and Characterization of Pin y 2, a Novel Vicilin Allergen of Pinus yunnanensis

Although pine nuts have gained increasing popularity, systematic studies of their allergens remain limited. Vicilin-like seed storage protein is an allergen in pine nuts. In this study, a 50 kDa protein from Pinus yunnanensis was purified and identified as a vicilin. Recombinant vicilin was expressed in Escherichia coli . Serological, spectroscopic, and bioinformatic methods were employed to evaluate its IgE/IgG-binding capacities, structural, and physicochemical characteristics. Results indicated that vicilin demonstrated potent IgE/IgG-binding capacities and was composed of 463 amino acids. Vicilin showed stability at 4–70 °C and pH 3–10, and no IgG cross-reactivity was observed with the tested species. P. yunnanensis vicilin was named Pin y 2 by the WHO/IUIS Allergen Nomenclature Sub-Committee. These findings provide a foundation for further investigation of vicilin and facilitate the development of specific detection and diagnostic approaches for pine nut allergy.