Purification, crystallization and preliminary X-ray diffraction analysis of human Gadd45γ

Gadd45, MyD118 and CR6 (also termed Gadd45 alpha, Gadd45 beta and Gadd45 gamma, respectively) comprise a family of proteins that play important roles in negative growth control, maintenance of genomic stability, DNA repair, cell-cycle control and apoptosis. Recombinant human Gadd45 gamma and its selenomethionine derivative were expressed in an Escherichia coli expression system and purified; they were then crystallized using the hanging-drop vapour-diffusion method. Diffraction-quality crystals were grown at 291 K using PEG 3350 as precipitant. Using synchrotron radiation, the best diffraction data were collected to 2.3 angstrom resolution for native crystals at 100 K; selenomethionyl derivative data were collected to 3.3 angstrom resolution. All the crystals belonged to space group I2(1)3, with approximate unit-cell parameters a = b = c = 126 angstrom