Crystallization and Preliminary X-ray Diffraction Studies of Recombinant Human Interleukin-5

Recombinant human interleukin-5 (rhIL-5) has been crystallized by the hanging drop vapor diffusion method using 0·1 M-Tris·HCL buffer (pH 8·5) containing 0·2 to 0·25 M-sodium acetate and 26 to 30% PEG 4000 at 22°C. The parallelepiped crystals belong to the space group C 2 with unit cell dimensions of a = 122·1 Å, b = 36·11 Å, c = 56·42 Å, β = 98·59°. They diffract to at least 2·0 Å resolution on a rotating anode X-ray source. The molecular mass weight of the protein and the volume of the unit cell suggest that the asymmetric unit contains one intermolecular disulfide-bonded homodimer.