2OLQ

How Does an Enzyme Recognize CO2?

Summary for 2OLQ

• Entry DOI: 10.2210/pdb2olq/pdb
• Descriptor: Phosphoenolpyruvate carboxykinase, MANGANESE (II) ION, MAGNESIUM ION, ... (6 entities in total)
• Functional Keywords: phosphoenolpyruvate carboxykinase, co2, lyase
• Biological source: Escherichia coli
• Cellular location: Cytoplasm: P22259
• Total number of polymer chains: 1
• Total formula weight: 60339.61

Authors

Puttick, J.,Goldie, H.,Cotelesage, J.J.,Rajabi, B.,Novakovski, B.,Delbaere, L.T. (deposition date: 2007-01-19, release date: 2007-06-12, Last modification date: 2023-08-30)

Primary citation

Cotelesage, J.J.,Puttick, J.,Goldie, H.,Rajabi, B.,Novakovski, B.,Delbaere, L.T.
How does an enzyme recognize CO2?
Int.J.Biochem.Cell Biol., 39:1204-1210, 2007

PubMed Abstract: 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.

PubMed: 17475535
DOI: 10.1016/j.biocel.2007.03.015

Experimental method

X-RAY DIFFRACTION (1.94 Å)