title: Secret of the major birch pollen allergen Bet v 1: identification of the physiological ligand.
abstract: The major birch pollen allergen Bet v 1 is the main elicitor of airborne type I allergies and belongs to the PR-10 family (pathogenesis-related proteins 10). Bet v 1 is the most extensively studied allergen, and is well characterized at a biochemical and immunological level; however, its physiological function remains elusive. In the present study, we identify Q3OS (quercetin-3-O-sophoroside) as the natural ligand of Bet v 1. We isolated Q3OS bound to Bet v 1 from mature birch pollen and confirmed its binding by reconstitution of the Bet v 1-Q3OS complex. Fluorescence and UV-visible spectroscopy experiments, as well as HSQC (heteronuclear single-quantum coherence) titration, and the comparison with model compounds, such as quercetin, indicated the specificity of Q3OS binding. Elucidation of the binding site by NMR combined with a computational model resulted in a more detailed understanding and shed light on the physiological function of Bet v 1. We postulate that the binding of Q3OS to Bet v 1 plays an important, but as yet unclear, role during the inflammation response and Bet v 1 recognition by IgE.
authors.affiliation: *Lehrstuhl Biopolymere und Forschungszentrum für Bio-Makromoleküle, Universität Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Seutter von Loetzen
authors.affiliation: †Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, 85354 Freising, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hoffmann
authors.affiliation: *Lehrstuhl Biopolymere und Forschungszentrum für Bio-Makromoleküle, Universität Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany.
authors.forename: Maximilian J
authors.initials: MJ
authors.lastname: Hartl
authors.affiliation: *Lehrstuhl Biopolymere und Forschungszentrum für Bio-Makromoleküle, Universität Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany.
authors.forename: Kristian
authors.initials: K
authors.lastname: Schweimer
authors.affiliation: †Biotechnology of Natural Products, Technische Universität München, Liesel-Beckmann-Str. 1, 85354 Freising, Germany.
authors.forename: Wilfried
authors.initials: W
authors.lastname: Schwab
authors.affiliation: *Lehrstuhl Biopolymere und Forschungszentrum für Bio-Makromoleküle, Universität Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Rösch
authors.affiliation: *Lehrstuhl Biopolymere und Forschungszentrum für Bio-Makromoleküle, Universität Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany.
authors.forename: Olivia
authors.initials: O
authors.lastname: Hartl-Spiegelhauer
mesh_terms: D052179:Antigens, Plant / Q000009:adverse effects / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029662:Betula / Q000009:adverse effects / Q000737:chemistry* / Q000254:growth & development / Q000276:immunology; D001665:Binding Sites; D018525:Germination; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism; D008024:Ligands; D008954:Models, Biological; D008958:Models, Molecular; D008968:Molecular Conformation; D062105:Molecular Docking Simulation; D019906:Nuclear Magnetic Resonance, Biomolecular; D010940:Plant Proteins / Q000009:adverse effects / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011058:Pollen / Q000009:adverse effects / Q000737:chemistry* / Q000254:growth & development / Q000276:immunology; D054817:Pollination / Q000276:immunology; D011794:Quercetin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000009:adverse effects / Q000378:metabolism; D057945:Self-Fertilization / Q000276:immunology; D013053:Spectrophotometry; D017186:Titrimetry; D041623:Tomography, Optical Coherence
chemical_list: D052179:Antigens, Plant; D006027:Glycosides; D008024:Ligands; D010940:Plant Proteins; D011994:Recombinant Proteins; C053376:pathogenesis-related proteins, plant; C055545:quercetin-3-O-sophoroside; D011794:Quercetin