The catalytic subunit of Dictyostelium CAMP-dependent protein kinase Role of the N-terminal domain and of the C-terminal residues in catalytic activity and stability

摘要: The C subunit of Dictyostelium cAMP-dependent protein kinase (PKA) is unusually large (73 kDa) due to the presence 330 amino acids N-terminal conserved catalytic core. sequence following core, including a C-terminal-Phe-Xaa-Xaa-Phe-COOH motif, highly conserved. We have characterized activity and stability subunits mutated in sequences outside core we analyzed their ability interact with R heat-stable protein-kinase inhibitor PKI. Mutants carrying deletions domain displayed little difference kinetic properties retained capacity be inhibited by PKI. In contrast, mutation one or both phenylalanine residues C-terminal motif resulted decrease proteins. Inhibition PKI were however unaffected. Sequence-comparison analysis other kinases revealed that a-Phe-Xaa-Xaa-Phe-motif present many Ser/Thr kinases, although its location at very end polypeptide particular feature PKA family. propose this may serve identify isoforms kinases.