Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of the structural domain of the nucleocapsid N protein from porcine reproductive and respiratory syndrome virus (PRRSV)

The structural domain of the PRRSV nucleocapsid N protein was overexpressed in Escherichia coli and purified to homogeneity. Crystals of the expressed protein, designated His-NΔ57, were obtained by hanging-drop vapour diffusion using PEG 3350 as precipitant at pH 6.5. A native data set from a frozen crystal was collected to 2.7 Å resolution using synchrotron radiation. The crystals belong to space group P3121 or P3221, with unit-cell parameters a = 44.41, c = 125.05, and contain a dimer in the asymmetric unit.