Expression of the phosphorylase kinase γ subunit catalytic domain in Escherichia coli

The catalytic subunit of phosphorylase b kinase (EC 2.7.1.38) and an engineered truncated form (γ-trc, residues 1-297) have been expressed in Escherichia coli. The truncated protein included the entire catalytic domain as defined by sequence alignment with other protein kinases but lacked the putative calmodulin binding domain. Full-length protein was produced in insoluble aggregates. Some activity was regenerated by solubilization in urea and dilution into renaturating buffer but the activity was found to be associated with a smaller molecular weight component. Full-length protein could not be refolded successfully