3tnq

Structure and Allostery of the PKA RIIb Tetrameric Holoenzyme

spinqualitylabelsall models 3tnq, resolution 3.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3tnq 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: ADP, MG NonStd Res: SEP, TPO Related: 3tnp, 3tnr Gene: Prkaca, rCG_51506 (Rattus norvegicus), Prkar2b (Mus musculus) Resources: FirstGlance, OCA, RCSB, PDBsum Function [KAP3_MOUSE] Regulatory subunit of the cAMP-dependent protein kinases involved in cAMP signaling in cells. Type II regulatory chains mediate membrane association by binding to anchoring proteins, including the MAP2 kinase. Publication Abstract from PubMed In its physiological state, cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) is a tetramer that contains a regulatory (R) subunit dimer and two catalytic (C) subunits. We describe here the 2.3 angstrom structure of full-length tetrameric RIIbeta(2):C(2) holoenzyme. This structure showing a dimer of dimers provides a mechanistic understanding of allosteric activation by cAMP. The heterodimers are anchored together by an interface created by the beta4-beta5 loop in the RIIbeta subunit, which docks onto the carboxyl-terminal tail of the adjacent C subunit, thereby forcing the C subunit into a fully closed conformation in the absence of nucleotide. Diffusion of magnesium adenosine triphosphate (ATP) into these crystals trapped not ATP, but the reaction products, adenosine diphosphate and the phosphorylated RIIbeta subunit. This complex has implications for the dissociation-reassociation cycling of PKA. The quaternary structure of the RIIbeta tetramer differs appreciably from our model of the RIalpha tetramer, confirming the small-angle x-ray scattering prediction that the structures of each PKA tetramer are different. Structure and allostery of the PKA RIIbeta tetrameric holoenzyme.,Zhang P, Smith-Nguyen EV, Keshwani MM, Deal MS, Kornev AP, Taylor SS Science. 2012 Feb 10;335(6069):712-6. PMID:22323819 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also CAMP-dependent protein kinase

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