PURIFICATION AND CRYSTALLIZATION OF THE CDK-ASSOCIATED PROTEIN PHOSPHATASE KAP EXPRESSED IN ESCHERICHIA-COLI

The kinase associated phosphatase (KAP) is a human dual specificity pr otein phosphatase that dephosphorylates the cell cycle control protein , cyclin dependent kinase-2 an Thr 160 in a cyclin dependent manner (P oon & Hunter, 1995). We report here the over-expression of KAP in Esch erichia coli as an N-terminal His-tagged protein using a modified pET- 28a T7-expression vector. The recombinant protein was purified to homo geneity and crystallized. The crystals diffract to 2.3 Angstrom resolu tion when exposed to synchrotron radiation and belong to space group P 6(1)22, or its enantiomorph P6(5)22. with unit cell dimensions cr = b = 74.5 Angstrom, c = 139.5 Angstrom.