Crystallizing catabolite gene activator protein with cAMP for structural analysis

The crystal structure of the CAP dimer with cAMP has provided many insights into the action of this gene regulatory protein. The CAP subunit is divided into two domains that are connected by a hinge region. The carboxy-terminal domains bind to DNA and show both sequence and structural homologies with many other gene regulatory proteins from bacteria and viruses. The amino-terminal domain forms a binding site for cAMP and has been used to model the cAMP-binding domains of the regulatory subunits of mammalian cAMP-dependent protein kinase.