2qzy

From Proteopedia

The structure of chicken mitochondrial PEPCK in complex with PEP

PDB ID 2qzy

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Structural highlights

2qzy is a 2 chain structure with sequence from Gallus gallus. This structure supersedes the now removed PDB entry 2fag. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.9Å
Ligands:	, , , , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

PCKGM_CHICK 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. Facilitates the recycling of lactate carbon in the liver.

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

Phosphoenolpyruvate carboxykinase catalyzes the reversible decarboxylation of oxaloacetic acid with the concomitant transfer of the gamma-phosphate of GTP to form PEP and GDP as the first committed step of gluconeogenesis and glyceroneogenesis. The three structures of the mitochondrial isoform of PEPCK reported are complexed with Mn2+, Mn2+-PEP, or Mn2+-malonate-Mn2+ GDP and provide the first observations of the structure of the mitochondrial isoform and insight into the mechanism of catalysis mediated by this enzyme. The structures show the involvement of the hyper-reactive cysteine (C307) in the coordination of the active site Mn2+. Upon formation of the PEPCK-Mn2+-PEP or PEPCK-Mn2+-malonate-Mn2+ GDP complexes, C307 coordination is lost as the P-loop in which it resides adopts a different conformation. The structures suggest that stabilization of the cysteine-coordinated metal geometry holds the enzyme as a catalytically incompetent metal complex and may represent a previously unappreciated mechanism of regulation. A third conformation of the mobile P-loop in the PEPCK-Mn2+-malonate-Mn2+ GDP complex demonstrates the participation of a previously unrecognized, conserved serine residue (S305) in mediating phosphoryl transfer. The ordering of the mobile active site lid in the PEPCK-Mn2+-malonate-Mn2+ GDP complex yields the first observation of this structural feature and provides additional insight into the mechanism of phosphoryl transfer.

Structural insights into the mechanism of PEPCK catalysis.,Holyoak T, Sullivan SM, Nowak T Biochemistry. 2006 Jul 11;45(27):8254-63. PMID:16819824^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Holyoak T, Sullivan SM, Nowak T. Structural insights into the mechanism of PEPCK catalysis. Biochemistry. 2006 Jul 11;45(27):8254-63. PMID:16819824 doi:10.1021/bi060269g