phosphopyruvate carboxykinase (adenosine triphosphate)
ATP:oxaloacetate carboxy-lyase (transphosphorylating)
There are several types of Phosphoenolpyruvate carboxykinases; E.C. 4.1.1.49 (ATP-dependent and found in plants and microorganisms), E.C. 4.1.1.32 (GTP-dependent and found in higher organism), and E.C. 4.1.1.38 (diphosphate-dependent). This enzyme belongs to the ATP-dependent one. Interestingly, lysine residue is coordinated to the divalent metal ion, as it is deprotonated (see [13] & [14]). This enzyme binds a magnesium ion, which is bound to beta- and gamma-phosphate groups of ATP, and a second divalent metal, which is bound between ATP and another substrate. Both the metal ions are involved in catalysis. According to the literature [3], [5], [6], [7], [11], [20] & [22], this enzyme catalyzes two successive reactions, (A) decarboxylation and (B) phophoryl transfer as follows; (A) Decarboxylation; Eliminative double-bond formation. (A1) A divalent metal ion such as manganese and calcium facilitates the bond cleavage between the mehtylene carbon and carboxylate (probably through a water). On the other hand, the leaving carboxylate group is stabilized by Tyr207 (of 2aq2). (A2) Bond cleavage occurs via E1-like mechanism, forming an enolpyruvate intermediate. (B) Transfer of phosphoryl group from ATP to enolepyruvate intermediate (see [6], [20] & [22]). (B1) In the initial stage, a divalent metal is bound to gamma-phosphate and two water, along with Asp269/His232/Lys213 (in the case of manganese). The oxygen of the enolate intermediate is away from the divalent metal ion (in the case of manganese). (B2) The magnesium ion, bound to the beta- and gamma-phosphate oxygens, stabilizes the negative charge developed on the leaving phosphate and transferred phosphate together with the sidechain of Lys254 and the mainchain amide of Gly251, and polarizes the P-O bond in the gamma-phosphoryl group by making the gamma-phosphate more electrophilic. (B3) (In the case of manganese ion as the second metal ion, the enol oxygen displaces a water molecule bound to the divalent metal, in order to be in line with the gamma-phosphate group.) (B4) The second metal ion neutralizes the electrostatic repulsion between the enol oxygen and phosphate group, along with Arg333. (B5) The enol oxygen makes a nucleophilic attack on the gamma-phosphorus atom. The transfer reaction occurs via SN-2-like mechanism.
Phosphoenolpyruvate Carboxykinase; domain 2
Phosphoenolpyruvate Carboxykinase; domain 1
Phosphoenolpyruvate Carboxykinase; domain 3
Carbon fixation in photosynthetic organisms
Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase: revised amino acid sequence, site-directed mutagenesis, and microenvironment characteristics of cysteines 365 and 458.
Gene- and activation-specific mechanisms for insulin inhibition of basal and glucocorticoid-induced insulin-like growth factor binding protein-1 and phosphoenolpyruvate carboxykinase transcription. Roles of forkhead and insulin response sequences.
The phosphoryl-transfer mechanism of Escherichia coli phosphoenolpyruvate carboxykinase from the use of AlF(3).
Crystal structure of the dimeric phosphoenolpyruvate carboxykinase (PEPCK) from Trypanosoma cruzi at 2 A resolution.
Lysine 213 and histidine 233 participate in Mn(II) binding and catalysis in Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase.
Evolutionary relationship between the bacterial HPr kinase and the ubiquitous PEP-carboxykinase: expanding the P-loop nucleotidyl transferase superfamily.
Urea-induced unfolding studies of free- and ligand-bound tetrameric ATP-dependent Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase. Influence of quaternary structure on protein conformational stability.
Crystal structure of human cytosolic phosphoenolpyruvate carboxykinase reveals a new GTP-binding site.
The effect of active site mutations in the oxaloacetate decarboxylase and pyruvate kinase-like activities of Anaerobiospirillum succiniciproducens phosphoenolpyruvate carboxykinase.
X-ray structure of a bifunctional protein kinase in complex with its protein substrate HPr.
Crystal structure of Escherichia coli phosphoenolpyruvate carboxykinase: a new structural family with the P-loop nucleoside triphosphate hydrolase fold.
Mechanisms of activation of phosphoenolpyruvate carboxykinase from Escherichia coli by Ca2+ and of desensitization by trypsin.
Structure/function studies of phosphoryl transfer by phosphoenolpyruvate carboxykinase.
Structure of PEP carboxykinase from the succinate-producing Actinobacillus succinogenes: a new conserved active-site motif.
Snapshot of an enzyme reaction intermediate in the structure of the ATP-Mg2+-oxalate ternary complex of Escherichia coli PEP carboxykinase.
Mg(2+)-Mn2+ clusters in enzyme-catalyzed phosphoryl-transfer reactions.
The strongly conserved lysine 256 of Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase is essential for phosphoryl transfer.
Mutation Arg336 to Lys in Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase originates an enzyme with increased oxaloacetate decarboxylase activity.
Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase: theoretical and experimental study of the effect of glutamic acid 284 on the protonation state of lysine 213.
Thermal stability of phosphoenolpyruvate carboxykinases from Escherichia coli, Trypanosoma brucei, and Saccharomyces cerevisiae.
Crystal structure of Anaerobiospirillum succiniciproducens PEP carboxykinase reveals an important active site loop.
Identification of reactive conserved histidines in phosphoenolpyruvate carboxykinases from Escherichia coli and Saccharomyces cerevisiae.
Structure and mechanism of phosphoenolpyruvate carboxykinase.
Characterization of the oxaloacetate decarboxylase and pyruvate kinase-like activities of Saccharomyces cerevisiae and Anaerobiospirillum succiniciproducens phosphoenolpyruvate carboxykinases.
HIS 232;ASP 269(2nd metal binding);THR 255(Magnesium binding)
HIS 216;ASP 253(2nd metal binding);THR 239(Magnesium binding)
HIS 205;ASP 242(2nd metal binding);THR 228(Magnesium binding)
HIS 225;ASP 263(2nd metal binding);THR 249(Magnesium binding)
HIS 1225;ASP 1263(2nd metal binding);THR 1249(Magnesium binding)