Related Experiment Video
Updated: Jun 11, 2026
Production of Human Norovirus Protruding Domains in E. coli for X-ray Crystallography
Published on: April 19, 2016
Crystallization and preliminary X-ray analysis of the chemokine-binding protein from orf virus (Poxviridae)
Rafael Miguez Couñago1, Stephen B Fleming, Andrew A Mercer
1Department of Biochemistry, University of Otago, New Zealand.
Abstract:
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 A resolution and belonged to the hexagonal space group P6(1)22 or its enantiomorph P6(5)22, with unit-cell parameters a = b = 75.62, c = 282.49 A, alpha = 90, beta = 90, gamma = 120 degrees.
Insights
Orf virus chemokine-binding protein (CBP) structure was determined to understand how it blocks immune cell recruitment. This research provides insights into viral immune evasion strategies.
Area of Science:
- Virology
- Structural Biology
- Immunology
Background:
- Orf virus (ORFV) uses a chemokine-binding protein (CBP) to suppress host immune responses.
- CBP inhibits immune cell infiltration by blocking chemokine signaling at infection sites.
Purpose of the Study:
- To elucidate the structural basis of ORFV CBP's interaction with chemokines.
- To understand the structure-function relationship of this viral immune evasion protein.
Main Methods:
- Crystallization of ORFV CBP using the sitting-drop vapour-diffusion method.
- Optimization of crystal quality with small-molecule additives.
- X-ray diffraction analysis to determine crystal structure and space group.
Main Results:
- ORFV CBP crystals were obtained with ammonium citrate as a precipitant.
- Diffraction data were collected to 2.50 Å resolution.
- The hexagonal space group P6(1)22 (or P6(5)22) was identified with specific unit-cell parameters.
Conclusions:
- The determined crystal structure provides a foundation for understanding ORFV CBP's mechanism of immune evasion.
- Structural insights can guide the development of novel antiviral strategies targeting viral chemokine binding.
