2gfc
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cAMP-dependent protein kinase PKA catalytic subunit with PKI-5-24
OverviewOverview
Controlling aberrant kinase-mediated cellular signaling is a major, strategy in cancer therapy; successful protein kinase inhibitors such as, Tarceva and Gleevec verify this approach. Specificity of inhibitors for, the targeted kinase(s), however, is a crucial factor for therapeutic, success. Based on homology modeling, we previously identified four amino, acids in the active site of Rho-kinase that likely determine inhibitor, specificities observed for Rho-kinase relative to protein kinase A (PKA), (in PKA numbering: T183A, L49I, V123M, and E127D), and a fifth (Q181K), that played a surprising role in PKA-PKB hybrid proteins. We have, systematically mutated these residues in PKA to their counterparts in, Rho-kinase, individually and in combination. Using four, Rho-kinase-specific, one PKA-specific, and one pan-kinase-specific, inhibitor, we measured the inhibitor-binding properties of the mutated, proteins and identify the roles of individual residues as specificity, determinants. Two combined mutant proteins, containing the combination of, mutations T183A and L49I, closely mimic Rho-kinase. Kinetic results, corroborate the hypothesis that side-chain identities form the major, determinants of selectivity. An unexpected result of the analysis is the, consistent contribution of the individual mutations by simple factors., Crystal structures of the surrogate kinase inhibitor complexes provide a, detailed basis for an understanding of these selectivity determinant, residues. The ability to obtain kinetic and structural data from these PKA, mutants, combined with their Rho-kinase-like selectivity profiles, make, them valuable for use as surrogate kinases for structure-based inhibitor, design.
About this StructureAbout this Structure
2GFC is a Protein complex structure of sequences from Bos taurus with OCT as ligand. Active as Non-specific serine/threonine protein kinase, with EC number 2.7.11.1 Full crystallographic information is available from OCA.
ReferenceReference
Structural analysis of protein kinase A mutants with Rho-kinase inhibitor specificity., Bonn S, Herrero S, Breitenlechner CB, Erlbruch A, Lehmann W, Engh RA, Gassel M, Bossemeyer D, J Biol Chem. 2006 Aug 25;281(34):24818-30. Epub 2006 May 12. PMID:16699172
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