X-ray structure of recombinant house dust mite allergen Der p 3

The X-ray structure of the Der p 3 allergen was solved at 2.25 Å resolution using the molecular replacement method. The most remarkable difference in conformation of the polypeptide chains between the Der p 3 allergen and bovine trypsin is observed in the disordered parts of the polypeptide chain where the degree of homology is lower. The active site of the Der p 3 allergen which involves the residues of catalytic triad Ser197, His 52, and Asp97 (Ser195, His57, and Asp102 in bovine trypsin) responsible for the specific binding of the positively charged substrates Asp191 (Asp189 in bovine trypsin) is in the cleft between the domains.