Definition and expression in E. coli of large fragments from the human lipid kinase phosphatidylinositol 4-kinase type III alpha, and purification of a 1100-residue N-terminal module

In this report, we use computational methods in order to delineate fragments of human PI4KA amenable to soluble production in Escherichia coli. We clone and express these fragments as GST-fusions and evaluate the soluble fraction of each protein. Finally, we produce and purify to homogeneity a 1100-residue PI4KA N-terminal fragment. Our results further suggest that PI4KA can be described as a two-module protein. They open the way to structural characterization of the N-terminal regulatory module of PI4KA.