Preliminary crystallographic analysis of the N-terminal domain of FILIA, a protein essential for embryogenesis.

FILIA is a component of the subcortical maternal complex that is essential for early stage embryogenesis. Its 6xHis-tagged N-terminal domain was expressed in Escherichia coli and purified to homogeneity. Two types of crystals formed under different crystallization conditions during screening. Orthorhombic crystals appeared in a solution containing 1.4 M ammonium sulfate, 0.1 M Tris pH 8.2 and 12% glycerol, while tetragonal crystals were obtained using 15% PEG 4000 mixed with 0.1 M HEPES pH 7.5 and 15% 2-propanol. High-quality diffraction data were collected from the two crystal forms to resolutions of 1.8 and 2.2 A, respectively, using synchrotron radiation. The Matthews coefficients indicated that the P2(1)2(1)2(1) and P4(1)2(1)2 crystals contained two molecules and one molecule per asymmetric unit, respectively. A selenomethionine-substituted sample failed to crystallize under the native conditions, but another orthorhombic crystal form was obtained under different conditions and anomalous diffraction data were collected.