4yw9

Structure of rat cytosolic pepck in complex with 3-mercaptopicolinic acid and GTP

spinqualitylabelsall models 4yw9, resolution 1.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4yw9 is a 1 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 1PE, 1WD, GTP, MN, MOH, NA Related: 4yw8 Activity: Phosphoenolpyruvate carboxykinase (GTP), with EC number 4.1.1.32 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [PCKGC_RAT] Catalyzes the conversion of oxaloacetate (OAA) to phosphoenolpyruvate (PEP), the rate-limiting step in the metabolic pathway that produces glucose from lactate and other precursors derived from the citric acid cycle. Publication Abstract from PubMed For almost 40 years, it has been known that tryptophan metabolites and picolinic acid analogues act as inhibitors of gluconeogenesis. Early studies observed that 3-mercaptopicolinic acid (MPA) was a potent hypoglycemic agent via inhibition of glucose synthesis through the specific inhibition of phosphoenolpyruvate carboxykinase (PEPCK) in the gluconeogenesis pathway. Despite prior kinetic investigation, the mechanism of the inhibition by MPA is unclear. To clarify the mechanism of inhibition exerted by MPA on PEPCK, we have undertaken structural and kinetic studies. The kinetic data in concert with crystallographic structures of PEPCK in complex with MPA and the substrates for the reaction illustrate that PEPCK is inhibited by the binding of MPA at two discrete binding sites: one acting in a competitive fashion with PEP/OAA ( approximately 10 muM) and the other acting at a previously unidentified allosteric site (Ki approximately 150 muM). The structural studies suggest that binding of MPA to the allosteric pocket stabilizes an altered conformation of the nucleotide-binding site that in turn reduces the affinity of the enzyme for the nucleotide. Inhibition and Allosteric Regulation of Monomeric Phosphoenolpyruvate Carboxykinase by 3-Mercaptopicolinic Acid.,Balan MD, Mcleod MJ, Lotosky WR, Ghaly M, Holyoak T Biochemistry. 2015 Sep 29;54(38):5878-87. doi: 10.1021/acs.biochem.5b00822. Epub , 2015 Sep 11. PMID:26322521 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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