Dissecting subdomains involved in multiple functions of the CK2beta subunit.

We have characterized several subdomains of the beta subunit of protein kinase CK2. The N-terminal half of the protein exhibits a pseudo-substrate segment in tandem with a polyamine binding domain responsible for the activation of the kinase by these polybasic compounds. Study of the chemical features of this polyamine binding site showed that polyamine analogs exhibiting the highest affinity for CK2 are the best CK2 activators.