Preparation of large volume casein kinase-2 crystals for neutron diffraction experiment

Shibazaki, Chie; Adachi, Motoyasu; Hiromoto, Takeshi; Shimizu, Rumi; Kuroki, Ryota

Casein kinase 2(CK2) is one of the ubiquitous Ser/Thr kinases and is involved in the cell cycle and the survival and proliferation of cells. In order to understand the biological function of the alpha catalytic subunit of CK2 (CK2a), we aim to analyze the structure of CK2a including information of the hydrogen and hydrating water molecule by neutron crystallography. The gene coding CK2a was expressed in E. coli, in which the mobile region and chemically reactive thiols were removed by amino acid mutation. The preparation of large crystals with inhibitor (Emodin and CX4945) was performed using a macro seeding method. Finally, large crystals with a volume of approximately 2 mm were reproducibly obtained. The crystals were dialyzed in the deuterated reagent and deuterium water. We have collected high resolution neutron diffraction images of emodin complex and CX-4945 complex at neutron beam line BioDIFF (FRM-II, Munich).