title: Mapping CD55 function. The structure of two pathogen-binding domains at 1.7 A.
abstract: Decay-accelerating factor (CD55), a regulator of the alternative and classical pathways of complement activation, is expressed on all serum-exposed cells. It is used by pathogens, including many enteroviruses and uropathogenic Escherichia coli, as a receptor prior to infection. We describe the x-ray structure of a pathogen-binding fragment of human CD55 at 1.7 A resolution containing two of the three domains required for regulation of human complement. We have used mutagenesis to map biological functions onto the molecule; decay-accelerating activity maps to a single face of the molecule, whereas bacterial and viral pathogens recognize a variety of different sites on CD55.
authors.affiliation: Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, United Kingdom.
authors.forename: Pamela
authors.initials: P
authors.lastname: Williams
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Chaudhry
authors.forename: Ian G
authors.initials: IG
authors.lastname: Goodfellow
authors.forename: Jason
authors.initials: J
authors.lastname: Billington
authors.forename: Robert
authors.initials: R
authors.lastname: Powell
authors.forename: O Brad
authors.initials: OB
authors.lastname: Spiller
authors.forename: David J
authors.initials: DJ
authors.lastname: Evans
authors.forename: Susan
authors.initials: S
authors.lastname: Lea
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D001665:Binding Sites; D018958:CD55 Antigens / Q000737:chemistry* / Q000502:physiology; D016466:CHO Cells; D003167:Complement Activation; D006224:Cricetinae; D018360:Crystallography, X-Ray; D006801:Humans; D011991:Receptors, Virus / Q000737:chemistry / Q000502:physiology; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D018958:CD55 Antigens; D011991:Receptors, Virus; D011994:Recombinant Proteins