3crl
Crystal structure of the PDHK2-L2 complex.
Structural highlights
FunctionPDK2_RAT Serine/threonine kinase that plays a key role in the regulation of glucose and fatty acid metabolism and homeostasis via phosphorylation of the pyruvate dehydrogenase subunits PDHA1 and PDHA2. This inhibits pyruvate dehydrogenase activity, and thereby regulates metabolite flux through the tricarboxylic acid cycle, down-regulates aerobic respiration and inhibits the formation of acetyl-coenzyme A from pyruvate. Inhibition of pyruvate dehydrogenase decreases glucose utilization and increases fat metabolism. Mediates cellular responses to insulin. Plays an important role in maintaining normal blood glucose levels and in metabolic adaptation to nutrient availability. Via its regulation of pyruvate dehydrogenase activity, plays an important role in maintaining normal blood pH and in preventing the accumulation of ketone bodies under starvation. Plays a role in the regulation of cell proliferation and in resistance to apoptosis under oxidative stress. Plays a role in p53/TP53-mediated apoptosis.[1] [2] [3] [4] [5] 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 PubMedPDHK2 is a mitochondrial protein kinase that phosphorylates pyruvate dehydrogenase complex, thereby down-regulating the oxidation of pyruvate. Here, we present the crystal structure of PDHK2 bound to the inner lipoyl-bearing domain of dihydrolipoamide transacetylase (L2) determined with or without bound adenylyl imidodiphosphate. Both structures reveal a PDHK2 dimer complexed with two L2 domains. Comparison with apo-PDHK2 shows that L2 binding causes rearrangements in PDHK2 structure that affect the L2- and E1-binding sites. Significant differences are found between PDHK2 and PDHK3 with respect to the structure of their lipoyllysine-binding cavities, providing the first structural support to a number of studies showing that these isozymes are markedly different with respect to their affinity for the L2 domain. Both structures display a novel type II potassium-binding site located on the PDHK2 interface with the L2 domain. Binding of potassium ion at this site rigidifies the interface and appears to be critical in determining the strength of L2 binding. Evidence is also presented that potassium ions are indispensable for the cross-talk between the nucleotide- and L2-binding sites of PDHK2. The latter is believed to be essential for the movement of PDHK2 along the surface of the transacetylase scaffold. Structural and functional insights into the molecular mechanisms responsible for the regulation of pyruvate dehydrogenase kinase 2.,Green T, Grigorian A, Klyuyeva A, Tuganova A, Luo M, Popov KM J Biol Chem. 2008 Jun 6;283(23):15789-98. Epub 2008 Apr 3. PMID:18387944[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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