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

The catalytic (alpha) subunit of protein kinase CK2 (CK2 alpha) 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 CZ, they have unit-cell parameters a = 142.6, b = 61.3, c = 45.6 Angstrom, beta = 103.3 degrees and diffract X-rays to at least 2.0 Angstrom resolution. The calculated crystal packing parameter is V-m = 2.47 Angstrom(3) Da(-1) suggesting that one CK2 alpha molecule is contained in the asymmetric unit and that the solvent content of the unit cell is 50%.