Expression, purification and crystallization of the catalytic subunit of protein kinase CK2 from Zea mays

The catalytic (α) subunit of protein kinase CK2 (CK2α) was originally cloned and overexpressed in the Escherichia coli strain pT7-7/BL21(DE3). The protein has been purified to homogeneity and crystallized. The crystals belong to the monoclinic space group C2, they have unit-cell parameters a = 142.6, b = 61.3, c = 45.6 Å, β = 103.3° and diffract X-rays to at least 2.0 Å resolution. The calculated crystal packing parameter is V_m = 2.47 ų Da⁻¹ suggesting that one CK2α molecule is contained in the asymmetric unit and that the solvent content of the unit cell is 50%.