Structure of a GTP-dependent Bacterial PEP-carboxykinase from Corynebacterium glutamicum

Journal Article · Mon Jun 23 04:00:00 EDT 2008 · Int. J. Biochem. Cell B.

DOI:https://doi.org/10.1016/j.biocel.2007.12.002· OSTI ID:1006606

Aich, Sanjukta; Prasad, Lata; Delbaere, Louis T.J. ^[1]

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1. Saskatchewan

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{sub 1} with four molecules per asymmetric unit. The 2.3 {angstrom} 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.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1006606
• Journal Information: Int. J. Biochem. Cell B., Journal Name: Int. J. Biochem. Cell B. Journal Issue: (8) ; 2008 Vol. 40
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
ANIMALS
BLOOD
CRYSTALS
DIMERS
ENZYMES
FASTING
GLUCOSE
GUANINE
HUMAN POPULATIONS
IONS
LEVELS
METALS
MOLECULES
PHOSPHOENOLPYRUVATE
PROTEINS
RESOLUTION
SPACE GROUPS
STOWING
SUBSTRATES
UNITS