title: Molecular interactions between a recombinant IgE antibody and the beta-lactoglobulin allergen.
abstract: Allergies are caused by the immune reaction to commonly harmless proteins, allergens. This reaction is typified by immunoglobulin E (IgE) antibodies. We report the crystal structure of an IgE Fab fragment in complex with beta-lactoglobulin (BLG), one of the major allergens of bovine milk. The solved structure shows how two IgE/Fab molecules bind the dimeric BLG. The epitope of BLG consists of six different short fragments of the polypeptide chain, which are located especially in the beta strands, covering a flat area on the allergen surface. All six CDR (complementary-determining region) loops of the IgE Fab participate in the binding of BLG. The light chain CDR loops are responsible for the binding of the flat beta sheet region of BLG. The IgE epitope is different from common IgG epitopes that are normally located in the exposed loop regions of antigens and observed also in the two recently determined allergen-IgG complexes.
authors.affiliation: Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland.
authors.forename: Merja
authors.initials: M
authors.lastname: Niemi
authors.forename: Sirpa
authors.initials: S
authors.lastname: Jylhä
authors.forename: Marja-Leena
authors.initials: ML
authors.lastname: Laukkanen
authors.forename: Hans
authors.initials: H
authors.lastname: Söderlund
authors.forename: Soili
authors.initials: S
authors.lastname: Mäkinen-Kiljunen
authors.forename: Johanna M
authors.initials: JM
authors.lastname: Kallio
authors.forename: Nina
authors.initials: N
authors.lastname: Hakulinen
authors.forename: Tari
authors.initials: T
authors.lastname: Haahtela
authors.forename: Kristiina
authors.initials: K
authors.lastname: Takkinen
authors.forename: Juha
authors.initials: J
authors.lastname: Rouvinen
mesh_terms: D000485:Allergens / Q000737:chemistry* / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D018360:Crystallography, X-Ray; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D007073:Immunoglobulin E / Q000737:chemistry* / Q000276:immunology; D007782:Lactoglobulins / Q000737:chemistry* / Q000276:immunology*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology
chemical_list: D000485:Allergens; D000939:Epitopes; D007782:Lactoglobulins; D011994:Recombinant Proteins; D007073:Immunoglobulin E