title: The crystal structure of an avian IgY-Fc fragment reveals conservation with both mammalian IgG and IgE.
abstract: Avian IgY is closely related to an ancestor of both mammalian IgG and IgE and thus provides insights into the evolution of antibody structure and function. A recombinant fragment of IgY-Fc consisting of a dimer of the Cupsilon3 and Cupsilon4 domains, Fcupsilon3-4, was expressed and crystallized and its X-ray structure determined to 1.75 A resolution. Fcupsilon3-4 is the only nonmammalian Fc fragment structure determined to date and provides the first structural evidence for an ancient origin of antibody architecture. The Fcupsilon3-4 structure reveals features common to both IgE-Fc and IgG-Fc, and the implications for IgY binding to its receptor are discussed.
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, and MRC-Asthma UK Centre in Allergic Mechanisms of Asthma, New Hunt's House, Guy's Campus, London SE1 1UL, United Kingdom.
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Taylor
authors.forename: Stella M
authors.initials: SM
authors.lastname: Fabiane
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Sutton
authors.forename: Rosaleen A
authors.initials: RA
authors.lastname: Calvert
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002645:Chickens / Q000276:immunology*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007073:Immunoglobulin E / Q000737:chemistry*; D007141:Immunoglobulin Fc Fragments / Q000737:chemistry*; D007074:Immunoglobulin G / Q000737:chemistry*; D007136:Immunoglobulins / Q000737:chemistry*; D008322:Mammals / Q000276:immunology*; D051379:Mice; D017433:Protein Structure, Secondary
chemical_list: C016512:IgY; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D007136:Immunoglobulins; D007073:Immunoglobulin E