Expression, purification, crystallization and preliminary X-ray analysis of a C-terminal fragment of the Epstein-Barr virus ZEBRA protein

A C-terminal fragment of the Epstein-Barr virus immediate-early transcription factor ZEBRA has been expressed as a recombinant protein in Escherichia coli and purified to homogeneity. The fragment behaves as a dimer in solution, consistent with the presence of a basic region leucine-zipper (bZIP) domain. Crystals of the fragment in complex with a DNA duplex were grown by the hanging-drop vapour-diffusion technique using polyethylene glycol 4000 and magnesium acetate as crystallization agents. Crystals diffract to better than 2.5 A resolution using synchrotron radiation (lambda = 0.976 A). Crystals belong to space group C2, with unit-cell parameters a = 94.2, b = 26.5, c = 98.1 A, beta = 103.9 degrees.