2olq

How Does an Enzyme Recognize CO2?

spinqualitylabelsall models 2olq, resolution 1.94Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2olq is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ATP, CO2, MG, MN Gene: pckA (Escherichia coli) Activity: Phosphoenolpyruvate carboxykinase (ATP), with EC number 4.1.1.49 Resources: FirstGlance, OCA, RCSB, PDBsum 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 (PCK) reversibly catalyzes the carboxylation of phosphoenolpyruvate to oxaloacetate. Carbon dioxide, and not bicarbonate ion, is the substrate utilized. Assays of the carboxylation reaction show that initial velocities are 7.6-fold higher when CO(2) is used instead of HCO(3)(-). Two Escherichia coli PCK-CO(2) crystal structures are presented here. The location of CO(2) is the same for both structures; however the orientation of CO(2) is significantly different, likely from the presence of a manganese ion in one of the structures. PCK and the other three known protein-CO(2) crystal structure complexes have been compared; all have CO(2) hydrogen bonding with a basic amino acid side chain (Arg65 or Lys213 in PCK), likely to polarize CO(2) to make the central carbon atom more electrophilic and thus more reactive. Kinetic studies found that the PCK mutant Arg65Gln increased the K(M) for substrates PEP and oxaloacetate but not for CO(2). The unchanged K(M) for CO(2) can be explained since the Arg65Gln mutant likely maintains a hydrogen bond to one of the oxygen atoms of carbon dioxide. How does an enzyme recognize CO2?,Cotelesage JJ, Puttick J, Goldie H, Rajabi B, Novakovski B, Delbaere LT Int J Biochem Cell Biol. 2007;39(6):1204-10. Epub 2007 Mar 30. PMID:17475535 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phosphoenolpyruvate carboxykinase

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