title: Crystal structure of the dog lipocalin allergen Can f 2: implications for cross-reactivity to the cat allergen Fel d 4.
abstract: The dog lipocalin allergen Can f 2 is an important cause of allergic sensitization in humans worldwide. Here, the first crystal structure of recombinant rCan f 2 at 1.45 A resolution displays a classical lipocalin fold with a conserved Gly-Xaa-Trp motif, in which Trp19 stabilizes the overall topology of the monomeric rCan f 2. Phe38 and Tyr84 localized on the L1 and L5 loops, respectively, control access to the highly hydrophobic calyx. Although the rCan f 2 calyx is nearly identical with the aero-allergens MUP1, Equ c 1 and A2U from mouse, horse and rat, respectively, no IgE cross-reactivity was found using sera from five mono-sensitized subjects. However, clear IgE cross-reactivity was demonstrated between Can f 2 and the cat allergen Fel d 4, although they share less than 22% sequence identity. This suggests a role for these allergens in co-sensitization between cat- and dog-allergic patients.
authors.affiliation: Centre for Infectious Medicine, F59, Department of Medicine Huddinge, Karolinska University Hospital Huddinge, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Chaithanya
authors.initials: C
authors.lastname: Madhurantakam
authors.forename: Ola B
authors.initials: OB
authors.lastname: Nilsson
authors.forename: Hannes
authors.initials: H
authors.lastname: Uchtenhagen
authors.forename: Jon
authors.initials: J
authors.lastname: Konradsen
authors.forename: Tiiu
authors.initials: T
authors.lastname: Saarne
authors.forename: Erik
authors.initials: E
authors.lastname: Högbom
authors.forename: Tatyana
authors.initials: T
authors.lastname: Sandalova
authors.forename: Hans
authors.initials: H
authors.lastname: Grönlund
authors.forename: Adnane
authors.initials: A
authors.lastname: Achour
mesh_terms: D000485:Allergens / Q000737:chemistry* / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D052179:Antigens, Plant; D002415:Cats; D003429:Cross Reactions; D003460:Crystallization; D018360:Crystallography, X-Ray; D004285:Dogs; D005260:Female; D006023:Glycoproteins / Q000737:chemistry* / Q000276:immunology*; D006801:Humans; D054834:Lipocalins / Q000737:chemistry* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C499337:Fel d 4 allergen, Felis domesticus; D006023:Glycoproteins; D054834:Lipocalins; C110827:allergen Can f 2