Probing the molecular basis of allergy - Three-dimensional structure of the bovine lipocalin allergen Bos d 2

The three-dimensional structure of the major bovine allergen Bos d 2 has be en determined by using x-ray diffraction at 1.8-Angstrom resolution, Struct urally Bos d 2 is a member of the lipocalin family comprising proteins with transport functions. There is a flat small cavity inside the Bos d 2 prote in core suitable for ligand binding, and it is possible that Glu(115) and A sn(37) inside the core are able to make hydrogen bonds with the ligand. Man y allergens from different animals belong to the lipocalin family. The amin o acid residue similarities between these lipocalins indicate putative regi ons for IgE binding. Comparison with the available allergen structures from other sources suggests that these allergens are roughly the same size and that their shape is more spherical than elliptical.