title: Three-dimensional structure and IgE-binding properties of mature fully active Der p 1, a clinically relevant major allergen.
abstract: BACKGROUND
  Der p 1 is a 25-kd allergen with cysteine protease activity. Sensitization to Der p 1 affects a large proportion of individuals with allergy, resulting in rhinitis, asthma, and/or atopic dermatitis.
  
  
  OBJECTIVE
  We determined the Der p 1 crystallographic structure to understand the relationships among structure, function, and allergenicity.
  
  
  METHODS
  Recombinant pro-Der p 1 was produced in Pichia pastoris and allowed to mature spontaneously before purification by a 2-step procedure. Protease activity was checked by using a fluorogenic peptide substrate. Allergenicity was analysed by IgE binding assays and basophil activation test. The determination of the 3-dimensional structure was obtained by X-ray crystallography at 1.9 A resolution.
  
  
  RESULTS
  The recombinant protein is fully active and expresses an allergenicity equivalent to its natural counterpart. Der p 1 exhibits a cysteine protease fold typical of the papain family, has a magnesium binding site, and forms dimers with a large interface. The crystal lattice shows that the dimers are tightly packed in a compact double layer of proteins. Such an assembly likely exists in dry fecal pellets, the natural form of allergen exposure, and appears ideal to interact with cell surface and trigger allergic inflammation.
  
  
  CONCLUSIONS
  We present here the 3-dimensional structural features of mature fully active Der p 1, one of the main allergens involved in human allergic diseases. This opens the possibility to evaluate the importance of enzymatic activity in pathology and possible new therapeutic interventions.
authors.affiliation: Center for Molecular and Vascular Biology, University of Leuven, Belgium.
authors.forename: Sonia
authors.initials: S
authors.lastname: de Halleux
authors.forename: Enrico
authors.initials: E
authors.lastname: Stura
authors.forename: Luc
authors.initials: L
authors.lastname: VanderElst
authors.forename: Vincent
authors.initials: V
authors.lastname: Carlier
authors.forename: Marc
authors.initials: M
authors.lastname: Jacquemin
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Saint-Remy
mesh_terms: D000485:Allergens / Q000096:biosynthesis / Q000276:immunology* / Q000648:ultrastructure*; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000096:biosynthesis / Q000276:immunology* / Q000648:ultrastructure*; D060829:Arthropod Proteins; D018360:Crystallography, X-Ray; D003546:Cysteine Endopeptidases; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D010843:Pichia; D011485:Protein Binding; D011487:Protein Conformation; D039981:Pyroglyphidae / Q000276:immunology; D011994:Recombinant Proteins / Q000096:biosynthesis; D013329:Structure-Activity Relationship
chemical_list: D000485:Allergens; D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1