Crystallization and preliminary X-ray analysis of the chemokine-binding protein from orf virus (Poxviridae)

摘要

The parapoxvirus orf virus (ORFV) encodes a chemokine-binding protein (CBP) that functions to downregulate the host’s immune response at the site of infection by blocking the chemokine-induced recruitment of immune cells. In order to shed light on the structural determinants of CBP–chemokine binding, ORFV CBP was crystallized as part of an ongoing structure–function study on this protein. ORFV CBP crystals were obtained by the sitting-drop vapour-diffusion technique using ammonium citrate as a precipitant. The crystal quality was greatly improved through the addition of small-molecule additives to the crystallization mother liquor. ORFV CBP crystals diffracted X-rays to 2.50 Å resolution and belonged to the hexagonal space group P6122 or its enantiomorph P6522, with unit-cell parameters a = b = 75.62, c = 282.49 Å, α = 90, β = 90, γ = 120°.