Identification, Expression, and Characterization of Pin y 2, a Novel Vicilin Allergen of <i>Pinus yunnanensis</i>

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 <i>Pinus yunnanensis</i> was purified and identified as a vicilin. Recombinant vicilin was expressed in <i>Escherichia coli</i>. 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. <i>P. yunnanensis</i> 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.