The Crystal Structure of Recombinant proDer p 1, a Major House Dust Mite Proteolytic Allergen

• Published in: The Journal of immunology (1950) Vol. 175; no. 6; pp. 3835 - 3845
• Main Authors: Meno, Kare, Thorsted, Peter B, Ipsen, Henrik, Kristensen, Ole, Larsen, Jorgen N, Spangfort, Michael D, Gajhede, Michael, Lund, Kaare
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 15.09.2005
• Subjects: Allergens - chemistry; Animals; Arthropod Proteins; Binding Sites; Cross Reactions; Crystallography, X-Ray; Dermatophagoides pteronyssinus; Epitopes; Genetic Engineering; Models, Molecular; Molecular Structure; Protein Conformation; Protein Precursors - chemistry; Pyroglyphidae - chemistry; Pyroglyphidae - immunology; Recombinant Proteins; Species Specificity; Substrate Specificity
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.175.6.3835

Allergy to house dust mite is among the most prevalent allergic diseases worldwide. Most house dust mite allergic patients react to Der p 1 from Dermatophagoides pteronyssinus, which is a cysteine protease. To avoid heterogeneity in the sample used for crystallization, a modified recombinant molecule was produced. The sequence of the proDer p 1 allergen was modified to reduce glycosylation and to abolish enzymatic activity. The resulting rproDer p 1 preparation was homogenous and stable and yielded crystals diffracting to a resolution of 1.61 A. The active site is located in a large cleft on the surface of the molecule. The 80-aa pro-peptide adopts a unique fold that interacts with the active site cleft and a substantial adjacent area on the mature region, excluding access to the cleft and the active site. Studies performed using crossed-line immunoelectrophoresis and IgE inhibition experiments indicated that several epitopes are covered by the pro-peptide and that the epitopes on the recombinant mature molecule are indistinguishable from those on the natural one. The structure confirms previous results suggesting a preference for aliphatic residues in the important P2 position in substrates. Sequence variations in related species are concentrated on the surface, which explains the existence of cross-reacting and species-specific antibodies. This study describes the first crystal structure of one of the clinically most important house dust mite allergens, the cysteine protease Der p 1.