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PDBsum entry 2zci
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Signaling protein, lyase
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PDB id
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2zci
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References listed in PDB file
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Key reference
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Title
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Structure of a gtp-Dependent bacterial pep-Carboxykinase from corynebacterium glutamicum.
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Authors
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S.Aich,
L.Prasad,
L.T.Delbaere.
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Ref.
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Int J Biochem Cell Biol, 2008,
40,
1597-1603.
[DOI no: ]
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PubMed id
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Abstract
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GTP-dependent phosphoenolpyruvate carboxykinase (PCK) is the key enzyme that
controls the blood glucose level during fasting in higher animals. Here we
report the first substrate-free structure of a GTP-dependent phosphoenolpyruvate
(PEP) carboxykinase from a bacterium, Corynebacterium glutamicum (CgPCK). The
protein crystallizes in space group P2(1) with four molecules per asymmetric
unit. The 2.3A resolution structure was solved by molecular replacement using
the human cytosolic PCK (hcPCK) structure (PDB ID: 1KHF) as the starting model.
The four molecules in the asymmetric unit pack as two dimers, and is an artifact
of crystal packing. However, the P-loop and the guanine binding loop of the
substrate-free CgPCK structure have different conformations from the other
published GTP-specific PCK structures, which all have bound substrates and/or
metal ions. It appears that a change in the P-loop and guanine binding loop
conformation is necessary for substrate binding in GTP-specific PCKs, as opposed
to overall domain movement in ATP-specific PCKs.
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