Renaturation and reconstitution of functional holoenzyme from recombinant subunits of casein kinase II expressed as inclusion bodies in E. coli.

Abstract

Casein kinase II (protein kinase CKII) is a heterotetramer consisting of two α and two β subunits (1,2). The α subunit can be expressed as two different gene products which are present as α and/or α′, depending on the tissue and species of origin. The β subunit is a single gene product in higher eukaryotes. A comparison of the sequences from a number of different species shows the α and β subunits are highly conserved (1,3). The heterotetramer is stable and the structure is dissociable only under denaturing conditions. Thus, complete physical, chemical and functional analysis of the enzyme at the molecular level is dependent on obtaining subunits capable of reconstituting into active CKII. This reconstituted CKII must have the capacity to interact with and react to the surrounding environment in an appropriate manner.