||The Betanodaviruses caused nerve necrosis in more than 40 species. The clinical symptoms of virus-infected fish include abnormal movement and darkness in body color, with mortality as high as 100%. To prevent and control the outbreak of NNV is a very important issue. |
There are two RNAs in the Betanodaviruses. RNA1 encodes RNA dependent RNA polymerase and RNA2 encodes capsid protein. To study the infection process of dragon grouper nervous necrosis virus (DGNNV), native virus and E. coli-produced virus-like particles (VLPs), and analysis revealed different impacts on VLP formation crystallization. Virus-like particles are formed in E. coli expressing the full-length ORF encoding the DGNNV capsid protein. The native protein was purified and crystallized by vapor diffusion method against mother liquor. The crystals grew to the size of 0.22-0.27 mm in one week and diffracted by X-rays to 7.5 Å resolution. The data were indexed in a primitive rhombohedral crystal system. Preliminary processing of the DGNNV VLPs diffracting data suggests that the crystal belong to space group R32; a = b = 353.00 Å, c = 800.40 Å, α = β = 90°, γ = 120°.
A total of 299 images were collected from a single VLP crystal by 60° diffracting range, 0.2° oscillation angle, and 30s exposure. 60,035 observed reflections were reduced to 23,268 unique reflections with an overall Rmerge of 18.2% and a completeness of 93.2%. Self-rotation function maps were calculated using the program POLARRFN from the CCP4 suite; spherical angles of κ = 72°, 120°, and 180° were for five-fold, three-fold and two-fold axes of icosahedral symmetry. This study is the first report about X-ray diffractometer the crystal of DGNNV capsid protein, which provides an example of DGNNV threedimensiond structure for other related Betanodaviruses.