title: Structural properties of a viral orthologue of cellular CD200 protein: KSHV vOX2.
abstract: Kaposi׳s sarcoma-associated herpesvirus (KSHV) vOX2 is a cell surface glycoprotein expressed during viral lytic replication to suppress host inflammatory reactions. Here we have characterised vOX2 with biochemical, biophysical and bioinformatics tools and as a result propose a 3-dimensional model for vOX2 based on structural and functional homology with the PD-L1 protein. To validate this model, vOX2 was characterised by analytical ultracentrifugation (AUC) and circular dichroism spectroscopy (CD). The results identified the potential glycosylation sites and revealed that vOX2 is predominantly a beta-folded molecule with an RGD adhesion motif exposed on the C-terminal domain. The protein exists in monomer-dimer equilibrium similar to its IgV-type folded homologues, with 30-36% glycosylation and the molecular weight of the extracellular fragment of molecule is 32.0-33.6 kDa, much less than 50 kDa. Thus, the structural similarity to PD-L1 verifies its immunomodulatory potential and the RGD motif suggests an adhesive capacity.
authors.affiliation: Inflammation and Inflammatory Diseases Research Centre, Medical school, Mashhad University of Medical Sciences, Mashhad, Iran; Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Abbas Ali
authors.initials: AA
authors.lastname: Amini
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle, Catherine Cookson Building, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Alexandra S
authors.initials: AS
authors.lastname: Solovyova
authors.affiliation: Department of Laboratory Sciences, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Sadeghian
authors.affiliation: Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Blackbourn
authors.affiliation: Inflammation and Inflammatory Diseases Research Centre, Medical school, Mashhad University of Medical Sciences, Mashhad, Iran. Electronic address: rezaeer@mums.ac.ir.
authors.forename: S A Rahim
authors.initials: SA
authors.lastname: Rezaee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry*; D060890:B7-H1 Antigen / Q000737:chemistry; D055592:Biophysical Phenomena; D016466:CHO Cells; D019295:Computational Biology; D003412:Cricetulus; D006031:Glycosylation; D019288:Herpesvirus 8, Human / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011487:Protein Conformation; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D040681:Structural Homology, Protein; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: D015703:Antigens, CD; D060890:B7-H1 Antigen; C423236:CD274 protein, human; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; C042739:antigens, CD200
keywords: CD200; Glycosylation; Homology modelling; KSHV; RGD domain; vOX2