Crystal structure of equine rhinitis A virus in complex with its sialic acid receptor.
Equine rhinitis A virus (ERAV) shares many features with foot-and-mouth disease virus (FMDV) and both are classified within the genus Aphthovirus of the family Picornaviridae. ERAV is used as a surrogate for FMDV research as it does not require high-level biosecurity. In contrast to FMDV, which uses integrins as cellular receptors, the receptor for ERAV has been reported to involve the sugar moiety sialic acid. This study confirmed the importance of sialic acid for cell entry by ERAV and reports the crystal structure of ERAV particles complexed with the receptor analogue 3'-sialyllactose. The receptor is attached to the rim of a capsid pit adjacent to the major immunogenic site and distinct from the sialic acid binding site used by a related picornavirus, the cardiovirus Theiler's murine encephalitis virus. The structure of the major antigenic determinant of the virus, previously identified from antibody escape mutations, is also described as the EF loop of VP1, which forms a hairpin stretching across the capsid surface close to the icosahedral fivefold axis, neighbouring the receptor-binding site, and spanning two protomeric units.
Fry
Elizabeth E
EE
Division of Structural Biology and Oxford Protein Production Facility, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Headington, Oxford OX3 7BN, UK.
Tuthill
Tobias J
TJ
Institute of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
Harlos
Karl
K
Division of Structural Biology and Oxford Protein Production Facility, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Headington, Oxford OX3 7BN, UK.
Walter
Thomas S
TS
Division of Structural Biology and Oxford Protein Production Facility, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Headington, Oxford OX3 7BN, UK.
Rowlands
David J
DJ
Institute of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
Stuart
David I
DI
Division of Structural Biology and Oxford Protein Production Facility, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Headington, Oxford OX3 7BN, UK.
D000956:Antigens, Viral / Q000737:chemistry; D005537:Aphthovirus / Q000737:chemistry* / Q000502:physiology; D001665:Binding Sites; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009844:Oligosaccharides / Q000737:chemistry* / Q000502:physiology; D020836:Protein Structure, Quaternary; D011991:Receptors, Virus / Q000737:chemistry* / Q000502:physiology; D010948:Viral Plaque Assay; D053586:Virus Internalization
C421467:3'-sialyllactose; D000956:Antigens, Viral; D009844:Oligosaccharides; D011991:Receptors, Virus