3idb

Crystal structure of (108-268)RIIb:C holoenzyme of cAMP-dependent protein kinaseCrystal structure of (108-268)RIIb:C holoenzyme of cAMP-dependent protein kinase

Structural highlights 3idb is a 2 chain structure with sequence from Mus musculus and Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: , NonStd Res: , Related: 3idc, 1cx4, 1rgs, 2qcs, 2qvs Gene: Pkaca, Prkaca (Mus musculus), Prkar2b (Rattus norvegicus) Activity: cAMP-dependent protein kinase, with EC number 2.7.11.11 Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The cAMP-dependent protein kinase catalytic (C) subunit is inhibited by two classes of functionally nonredundant regulatory (R) subunits, RI and RII. Unlike RI subunits, RII subunits are both substrates and inhibitors. Because RIIbeta knockout mice have important disease phenotypes, the RIIbeta holoenzyme is a target for developing isoform-specific agonists and/or antagonists. We also know little about the linker region that connects the inhibitor site to the N-terminal dimerization domain, although this linker determines the unique globular architecture of the RIIbeta holoenzyme. To understand how RIIbeta functions as both an inhibitor and a substrate and to elucidate the structural role of the linker, we engineered different RIIbeta constructs. In the absence of nucleotide, RIIbeta(108-268), which contains a single cyclic nucleotide binding domain, bound C subunit poorly, whereas with AMP-PNP, a non-hydrolyzable ATP analog, the affinity was 11 nM. The RIIbeta(108-268) holoenzyme structure (1.62 A) with AMP-PNP/Mn(2+) showed that we trapped the RIIbeta subunit in an enzyme:substrate complex with the C subunit in a closed conformation. The enhanced affinity afforded by AMP-PNP/Mn(2+) may be a useful strategy for increasing affinity and trapping other protein substrates with their cognate protein kinase. Because mutagenesis predicted that the region N-terminal to the inhibitor site might dock differently to RI and RII, we also engineered RIIbeta(102-265), which contained six additional linker residues. The additional linker residues in RIIbeta(102-265) increased the affinity to 1.6 nM, suggesting that docking to this surface may also enhance catalytic efficiency. In the corresponding holoenzyme structure, this linker docks as an extended strand onto the surface of the large lobe. This hydrophobic pocket, formed by the alphaF-alphaG loop and conserved in many protein kinases, also provides a docking site for the amphipathic helix of PKI. This novel orientation of the linker peptide provides the first clues as to how this region contributes to the unique organization of the RIIbeta holoenzyme. Novel isoform-specific interfaces revealed by PKA RIIbeta holoenzyme structures.,Brown SH, Wu J, Kim C, Alberto K, Taylor SS J Mol Biol. 2009 Nov 13;393(5):1070-82. Epub 2009 Sep 11. PMID:19748511 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also CAMP-dependent protein kinase

spinqualitylabelsall models 3idb, resolution 1.62Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image