title: Structures of Orf Virus Chemokine Binding Protein in Complex with Host Chemokines Reveal Clues to Broad Binding Specificity.
abstract: The chemokine binding protein (CKBP) from orf virus (ORFV) binds with high affinity to chemokines from three classes, C, CC, and CXC, making it unique among poxvirus CKBPs described to date. We present its crystal structure alone and in complex with three CC chemokines, CCL2, CCL3, and CCL7. ORFV CKBP possesses a β-sandwich fold that is electrostatically and sterically complementary to its binding partners. Chemokines bind primarily through interactions involving the N-terminal loop and a hydrophobic recess on the ORFV CKBP β-sheet II surface, and largely polar interactions between the chemokine 20s loop and a negatively charged surface groove located at one end of the CKBP β-sheet II surface. ORFV CKBP interacts with leukocyte receptor and glycosaminoglycan binding sites found on the surface of bound chemokines. SEC-MALLS and chromatographic evidence is presented supporting that ORFV CKBP is a dimer in solution over a broad range of protein concentrations.
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Rafael M
authors.initials: RM
authors.lastname: Couñago
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand; School of Biological Sciences, Bangor University, Bangor LL57 2UW, UK.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Knapp
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand; Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Nakatani
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Fleming
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Michael
authors.initials: M
authors.lastname: Corbett
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Lyn M
authors.initials: LM
authors.lastname: Wise
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Mercer
authors.affiliation: Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand. Electronic address: kurt.krause@otago.ac.nz.
authors.forename: Kurt L
authors.initials: KL
authors.lastname: Krause
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D018925:Chemokines / Q000737:chemistry*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D057809:HEK293 Cells; D006801:Humans; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009923:Orf virus / Q000737:chemistry*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D012996:Solutions; D014764:Viral Proteins / Q000737:chemistry*
chemical_list: D018925:Chemokines; D012996:Solutions; D014764:Viral Proteins