Purification and crystallization of Cor a 9, a major hazelnut allergen.

Hazelnut (Corylus avellana) is one of the food sources that induce allergic reaction in a subpopulation of people with food allergy. The 11S legumin-like seed-storage protein from hazelnut has been identified as one of the major hazelnut allergens and named Cor a 9. In this study, Cor a 9 was extracted from hazelnut kernels using a high-salt solution and was purified by desalting out and FPLC to a highly purified state. Diffraction-quality single crystals were obtained using the hanging-drop vapour-diffusion method. Diffraction data were collected and a structure solution has been obtained by molecular-replacement calculations. Further refinement of the structure is currently in progress.