4X9E

DEOXYGUANOSINETRIPHOSPHATE TRIPHOSPHOHYDROLASE from Escherichia coli with two DNA effector molecules


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.10 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.167 
  • R-Value Observed: 0.170 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structure of Escherichia coli dGTP Triphosphohydrolase: A HEXAMERIC ENZYME WITH DNA EFFECTOR MOLECULES.

Singh, D.Gawel, D.Itsko, M.Hochkoeppler, A.Krahn, J.M.London, R.E.Schaaper, R.M.

(2015) J Biol Chem 290: 10418-10429

  • DOI: 10.1074/jbc.M115.636936
  • Primary Citation of Related Structures:  
    4X9E, 4XDS

  • PubMed Abstract: 
  • The Escherichia coli dgt gene encodes a dGTP triphosphohydrolase whose detailed role still remains to be determined. Deletion of dgt creates a mutator phenotype, indicating that the dGTPase has a fidelity role, possibly by affecting the cellular dNTP ...

    The Escherichia coli dgt gene encodes a dGTP triphosphohydrolase whose detailed role still remains to be determined. Deletion of dgt creates a mutator phenotype, indicating that the dGTPase has a fidelity role, possibly by affecting the cellular dNTP pool. In the present study, we have investigated the structure of the Dgt protein at 3.1-Å resolution. One of the obtained structures revealed a protein hexamer that contained two molecules of single-stranded DNA. The presence of DNA caused significant conformational changes in the enzyme, including in the catalytic site of the enzyme. Dgt preparations lacking DNA were able to bind single-stranded DNA with high affinity (Kd ∼ 50 nM). DNA binding positively affected the activity of the enzyme: dGTPase activity displayed sigmoidal (cooperative) behavior without DNA but hyperbolic (Michaelis-Menten) kinetics in its presence, consistent with a specific lowering of the apparent Km for dGTP. A mutant Dgt enzyme was also created containing residue changes in the DNA binding cleft. This mutant enzyme, whereas still active, was incapable of DNA binding and could no longer be stimulated by addition of DNA. We also created an E. coli strain containing the mutant dgt gene on the chromosome replacing the wild-type gene. The mutant also displayed a mutator phenotype. Our results provide insight into the allosteric regulation of the enzyme and support a physiologically important role of DNA binding.


    Organizational Affiliation

    From the Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, schaaper@niehs.nih.gov.



Macromolecules

Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Deoxyguanosinetriphosphate triphosphohydrolaseABCDEF505Escherichia coli K-12Mutation(s): 0 
Gene Names: dgtb0160JW0156
EC: 3.1.5.1
Find proteins for P15723 (Escherichia coli (strain K12))
Explore P15723 
Go to UniProtKB:  P15723
Protein Feature View
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  • Reference Sequence
  • Find similar nucleic acids by:  Sequence   |   Structure
  • Entity ID: 2
    MoleculeChainsLengthOrganismImage
    RNA (5'-R(P*CP*CP*C)-3')G, H3Escherichia coli
    Small Molecules
    Ligands 1 Unique
    IDChainsName / Formula / InChI Key2D Diagram3D Interactions
    MG
    Query on MG

    Download CCD File 
    A, B
    MAGNESIUM ION
    Mg
    JLVVSXFLKOJNIY-UHFFFAOYSA-N
     Ligand Interaction
    Experimental Data & Validation

    Experimental Data

    • Method: X-RAY DIFFRACTION
    • Resolution: 3.10 Å
    • R-Value Free: 0.223 
    • R-Value Work: 0.167 
    • R-Value Observed: 0.170 
    • Space Group: P 21 21 21
    Unit Cell:
    Length ( Å )Angle ( ˚ )
    a = 136.8α = 90
    b = 159.8β = 90
    c = 190γ = 90
    Software Package:
    Software NamePurpose
    PHENIXrefinement
    HKL-2000data reduction
    HKL-2000data scaling
    MOLREPphasing

    Structure Validation

    View Full Validation Report



    Entry History 

    Deposition Data

    Revision History 

    • Version 1.0: 2015-02-25
      Type: Initial release
    • Version 1.1: 2015-03-04
      Changes: Database references
    • Version 1.2: 2015-04-29
      Changes: Database references