Crystallization and initial X-ray diffraction studies of scaffolding protein (gp7) of bacteriophage ϕ29

The Bacillus subtilis bacteriophage phi 29 scaffolding protein (gp7) has been crystallized by the hanging-drop vapour-diffusion method at 293 K. Two new distinct crystal forms that both differed from a previously crystallized and solved scaffolding protein were grown under the same conditions. Form I belongs to the primitive tetragonal space group P4(1)2(1)2, with unit-cell parameters a = b = 77.13, c = 37.12 angstrom. Form II crystals exhibit an orthorhombic crystal form, with space group C222 and unit-cell parameters a = 107.50, b = 107. 80, c = 37.34 angstrom. Complete data sets have been collected to 1.78 and 1.80 angstrom for forms I and II, respectively, at 100 K using Cu K alpha X-rays from a rotating-anode generator. Calculation of a V-M value of 2.46 angstrom(3) Da(-1) for form I suggests the presence of one molecule in the asymmetric unit, corresponding to a solvent content of 50.90%, whereas form II has a V-M of 4.80 angstrom(3) Da(-1) with a solvent content of 48.76% and two molecules in the asymmetric unit. The structures of both crystal forms are being determined by the molecular-replacement method using the coordinates of the published crystal structure of gp7.