title: The structure of echovirus type 12 bound to a two-domain fragment of its cellular attachment protein decay-accelerating factor (CD 55).
abstract: Echovirus type 12 (EV12), an Enterovirus of the Picornaviridae family, uses the complement regulator decay-accelerating factor (DAF, CD55) as a cellular receptor. We have calculated a three-dimensional reconstruction of EV12 bound to a fragment of DAF consisting of short consensus repeat domains 3 and 4 from cryo-negative stain electron microscopy data (EMD code 1057). This shows that, as for an earlier reconstruction of the related echovirus type 7 bound to DAF, attachment is not within the viral canyon but occurs close to the 2-fold symmetry axes. Despite this general similarity our reconstruction reveals a receptor interaction that is quite different from that observed for EV7. Fitting of the crystallographic co-ordinates for DAF(34) and EV11 into the reconstruction shows a close agreement between the crystal structure of the receptor fragment and the density for the virus-bound receptor, allowing unambiguous positioning of the receptor with respect to the virion (PDB code 1UPN). Our finding that the mode of virus-receptor interaction in EV12 is distinct from that seen for EV7 raises interesting questions regarding the evolution and biological significance of the DAF binding phenotype in these viruses.
authors.affiliation: Medical Research Council Virology Unit, Church Street, Glasgow, G11 5JR, United Kingdom. d.bhella@vir.gla.ac.uk
authors.forename: David
authors.initials: D
authors.lastname: Bhella
authors.forename: Ian G
authors.initials: IG
authors.lastname: Goodfellow
authors.forename: Pietro
authors.initials: P
authors.lastname: Roversi
authors.forename: David
authors.initials: D
authors.lastname: Pettigrew
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Chaudhry
authors.forename: David J
authors.initials: DJ
authors.lastname: Evans
authors.forename: Susan M
authors.initials: SM
authors.lastname: Lea
mesh_terms: D001665:Binding Sites; D018958:CD55 Antigens / Q000378:metabolism* / Q000648:ultrastructure*; D003198:Computer Simulation; D003460:Crystallization; D018360:Crystallography, X-Ray; D029822:Enterovirus B, Human / Q000378:metabolism* / Q000648:ultrastructure*; D007091:Image Processing, Computer-Assisted; D008854:Microscopy, Electron; D008958:Models, Molecular
chemical_list: D018958:CD55 Antigens