Peptide substrates of cyclic nucleotide-dependent protein kinases

摘要: This chapter focuses primarily on new developments in understanding of the similarities and differences recognition peptide substrates by PKA PKG identification important residues enzyme substrate recognition. The cyclic nucleotide-dependent protein kinases cAMP cGMP-dependent (PKA PKG) are closely related enzymes, with approximately 50 percent sequence identity. These two have similar specificities; particular, both show a strong preference for Arg at positions (-3) (-2) substrates. crystal structure revealed multiple contacts between these side chains enzyme. There specificity enzymes particularly (+1) site, having higher hydrophobic residues. However, site only found 40 substrates, possibly because phosphorylation sites must be hydrophilic enough to located surface protein. Although is more stringent its requirement (-1), (+2) (+3) than PKA, there substantial overlap specificity, expected share some as case cystic fibrosis transmembrane conductance regulator.