2ZCI image
Entry Detail
PDB ID:
2ZCI
Title:
Structure of a GTP-dependent bacterial PEP-carboxykinase from Corynebacterium glutamicum
Biological Source:
PDB Version:
Deposition Date:
2007-11-09
Release Date:
2008-04-15
Method Details:
Experimental Method:
Resolution:
2.30 Å
R-Value Free:
0.27
R-Value Work:
0.18
R-Value Observed:
0.19
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Phosphoenolpyruvate carboxykinase [GTP]
Chain IDs:A, B, C, D
Chain Length:610
Number of Molecules:4
Biological Source:Corynebacterium glutamicum
Primary Citation
Structure of a GTP-dependent bacterial PEP-carboxykinase from Corynebacterium glutamicum.
Int.J.Biochem.Cell Biol. 40 1597 1603 (2008)
PMID: 18234538 DOI: 10.1016/j.biocel.2007.12.002

Abstact

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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