Mapping CD55 function. The structure of two pathogen-binding domains at 1.7 A.
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.
Williams
Pamela
P
Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, United Kingdom.
Chaudhry
Yasmin
Y
Goodfellow
Ian G
IG
Billington
Jason
J
Powell
Robert
R
Spiller
O Brad
OB
Evans
David J
DJ
Lea
Susan
S
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
D018958:CD55 Antigens; D011991:Receptors, Virus; D011994:Recombinant Proteins