title: Cor a 14, the allergenic 2S albumin from hazelnut, is highly thermostable and resistant to gastrointestinal digestion.
abstract: METHODS
  Allergens from nuts frequently induce severe allergic reactions in sensitive individuals. The aim of this study was to elucidate the physicochemical characteristics of natural Cor a 14, the 2S albumin from hazelnut.
  
  
  RESULTS
  Cor a 14 was purified from raw hazelnuts using a combination of precipitation and chromatographic techniques. The protein was analyzed using gel electrophoresis, MS, and far-UV circular dichroism (CD) analyses. The immunoglobulin E (IgE) binding of native, heat-treated, and in vitro digested Cor a 14 was studied. We identified two different Cor a 14 isoforms and showed microclipping at the C-terminus. CD spectra at room temperature showed the typical characteristics of 2S albumins, and temperatures of more than 80°C were required to start unfolding of Cor a 14 demonstrating its high stability to heat treatment. In vitro digestion experiments revealed that Cor a 14 is resistant to proteolytic degradation. Native and heat-treated protein was recognized by sera from hazelnut allergic patients. However, denaturation of the allergen led to significantly reduced IgE binding.
  
  
  CONCLUSIONS
  We identified two different isoforms of Cor a 14 displaying high stability under heating and gastric and duodenal conditions. Data from IgE-binding experiments revealed the existence of both, linear and conformational epitopes.
authors.affiliation: Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Sabine
authors.initials: S
authors.lastname: Pfeifer
authors.affiliation: Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Merima
authors.initials: M
authors.lastname: Bublin
authors.affiliation: Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Pawel
authors.initials: P
authors.lastname: Dubiela
authors.affiliation: VetCore Facility, University of Veterinary Medicine, Vienna, Austria.
authors.forename: Karin
authors.initials: K
authors.lastname: Hummel
authors.affiliation: Institute of Molecular Biosciences, Structural Biology, University of Graz, Graz, Austria.
authors.forename: Judith
authors.initials: J
authors.lastname: Wortmann
authors.affiliation: Institute of Molecular Biosciences, Structural Biology, University of Graz, Graz, Austria.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hofer
authors.affiliation: Institute of Molecular Biosciences, Structural Biology, University of Graz, Graz, Austria.
authors.forename: Walter
authors.initials: W
authors.lastname: Keller
authors.affiliation: Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Radauer
authors.affiliation: Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Karin
authors.initials: K
authors.lastname: Hoffmann-Sommergruber
mesh_terms: D000485:Allergens / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D052179:Antigens, Plant / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D004063:Digestion; D006358:Hot Temperature; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D055550:Protein Stability; D017433:Protein Structure, Secondary; D059748:Proteolysis
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C000594310:Cor a 14 allergen, hazelnut; D020033:Protein Isoforms; D007073:Immunoglobulin E
keywords: 2S albumin; Allergen; Cor a 14; Food allergy; Hazelnut (Corylus avellana)