EFFECT OF INHIBITORS OF PROTEIN KINASE CK2 ON THE ACTIVITY ITS CATALYTIC SUBUNITS СК2α AND СК2α′

The effect of protein kinase CK2 inhibitors (with IC50 from 0.004 μM to 0.7 μM) from different chemical classes on the activity of СК2α and СК2α′ recombinant proteins has been studied. Biochemical tests shown that isozymes had different sensitivity toward the same compounds. The most isoform-selective inhibitor was 4′-hydroxyflavone derivative (FLC26) with IC50 value 0.020 μM (CK2α) and 0.003 μM (CK2α′). To explain the difference between influences of FLC26 on the activities of two CK2 catalytic subunits their complexes with ATP-binding site of CK2α and CK2α′ were analyzed using molecular modeling techniques. The data obtained by molecular dynamics simulation (10 ns) has not provided a clear explanation of the difference between the inhibitory potency of the compound FLC26 towards the CK2 catalytic subunits. Thus, the reasons underlying the different activities of the same inhibitor on CKα and CKα′ require further investigations. An effective approach for this purpose would be X-ray analysis of complexes ?compound FLC26- CKα/CKα′?.