Crystallization and preliminary crystallographic study of human CksHs1: a cell cycle regulatory protein.

The cell cycle regulatory protein CksHs1 has been crystallized in a form suitable for X-ray studies. CksHs1 crystals were grown in the presence of vanadate, a phosphatase inhibitor, but were also obtained with phosphate or tungstate as a cofactor. They belong to the hexagonal space group P6(1)22 with unit cell dimensions: a = b = 94 A, c = 131.6 A, and gamma = 120 degrees. The crystals grown in the presence of vanadate diffract X-rays to at least 2.8 A. Molecular replacement results from the homologous human CksHs2 structure reveal that a dimer forms the crystal habit, giving the unusual Vm value of 4.4 A3/Da or a solvent content of 72%.