2olr: Difference between revisions

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Crystal structure of Escherichia coli phosphoenolpyruvate carboxykinase complexed with carbon dioxide, Mg2+, ATP

OverviewOverview

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.

About this StructureAbout this Structure

2OLR is a Single protein structure of sequence from Escherichia coli with , , and as ligands. Active as Phosphoenolpyruvate carboxykinase (ATP), with EC number 4.1.1.49 Full crystallographic information is available from OCA.

ReferenceReference

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

Page seeded by OCA on Thu Feb 21 18:19:52 2008

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 ==Overview==
-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.
+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.
 ==About this Structure==
@@ Line 10: / Line 10: @@
 ==Reference==
-How does an enzyme recognize CO(2)?, 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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17475535 17475535]
+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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17475535 17475535]
 [[Category: Escherichia coli]]
 [[Category: Phosphoenolpyruvate carboxykinase (ATP)]]
 [[Category: Single protein]]
-[[Category: Cotelesage, J.J.]]
+[[Category: Cotelesage, J J.]]
-[[Category: Delbaere, L.T.]]
+[[Category: Delbaere, L T.]]
 [[Category: Goldie, H.]]
 [[Category: Novakovski, B.]]
@@ Line 27: / Line 27: @@
 [[Category: carboxykinase]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 14:55:27 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:19:52 2008''