2HVH

ddCTP:O6MeG pair in the polymerase active site (0 position)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.49 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.201 

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This is version 2.0 of the entry. See complete history


Literature

The structural basis for the mutagenicity of O6-methyl-guanine lesions.

Warren, J.J.Forsberg, L.J.Beese, L.S.

(2006) Proc Natl Acad Sci U S A 103: 19701-19706

  • DOI: 10.1073/pnas.0609580103
  • Primary Citation of Related Structures:  
    2HHQ, 2HHX, 2HHW, 2HHV, 2HHU, 2HHT, 2HHS, 2HW3, 2HVI, 2HVH

  • PubMed Abstract: 
  • Methylating agents are widespread environmental carcinogens that generate a broad spectrum of DNA damage. Methylation at the guanine O(6) position confers the greatest mutagenic and carcinogenic potential. DNA polymerases insert cytosine and thymine with similar efficiency opposite O(6)-methyl-guanine (O6MeG) ...

    Methylating agents are widespread environmental carcinogens that generate a broad spectrum of DNA damage. Methylation at the guanine O(6) position confers the greatest mutagenic and carcinogenic potential. DNA polymerases insert cytosine and thymine with similar efficiency opposite O(6)-methyl-guanine (O6MeG). We combined pre-steady-state kinetic analysis and a series of nine x-ray crystal structures to contrast the reaction pathways of accurate and mutagenic replication of O6MeG in a high-fidelity DNA polymerase from Bacillus stearothermophilus. Polymerases achieve substrate specificity by selecting for nucleotides with shape and hydrogen-bonding patterns that complement a canonical DNA template. Our structures reveal that both thymine and cytosine O6MeG base pairs evade proofreading by mimicking the essential molecular features of canonical substrates. The steric mimicry depends on stabilization of a rare cytosine tautomer in C.O6MeG-polymerase complexes. An unusual electrostatic interaction between O-methyl protons and a thymine carbonyl oxygen helps stabilize T.O6MeG pairs bound to DNA polymerase. Because DNA methylators constitute an important class of chemotherapeutic agents, the molecular mechanisms of replication of these DNA lesions are important for our understanding of both the genesis and treatment of cancer.


    Organizational Affiliation

    Department of Biochemistry, Duke University Medical Center, Box 3711, Durham, NC 27710, USA.



Macromolecules

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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
DNA Polymerase IE [auth A], F [auth D]580Geobacillus stearothermophilusMutation(s): 0 
Gene Names: polA
EC: 2.7.7.7
UniProt
Find proteins for Q45458 (Geobacillus stearothermophilus)
Explore Q45458 
Go to UniProtKB:  Q45458
Protein Feature View
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  • Reference Sequence
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  • Entity ID: 1
    MoleculeChainsLengthOrganismImage
    5'-D(*CP*CP*TP*GP*AP*CP*TP*CP*(DDG))-3'A [auth B], C [auth E]9N/A
    Protein Feature View
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    • Reference Sequence
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    • Entity ID: 2
      MoleculeChainsLengthOrganismImage
      5'-D(*CP*A*TP*(6OG)P*CP*GP*AP*GP*TP*CP*AP*GP*G)-3'B [auth C], D [auth F]13N/A
      Protein Feature View
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      • Reference Sequence
      Oligosaccharides

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      Entity ID: 4
      MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
      beta-D-fructofuranose-(2-1)-alpha-D-glucopyranoseG, H, I2N/A Oligosaccharides Interaction
      Glycosylation Resources
      GlyTouCan:  G05551OP
      GlyCosmos:  G05551OP
      Small Molecules
      External Ligand Annotations 
      IDBinding Affinity (Sequence Identity %)
      DCTKd :  17900   nM  PDBBind
      Biologically Interesting Molecules (External Reference) 1 Unique
      Entity ID: 4
      IDChainsNameType/Class2D Diagram3D Interactions
      PRD_900003
      Query on PRD_900003
      G, H, IsucroseOligosaccharide /  Nutrient Ligand Interaction
      Experimental Data & Validation

      Experimental Data

      • Method: X-RAY DIFFRACTION
      • Resolution: 2.49 Å
      • R-Value Free: 0.262 
      • R-Value Work: 0.201 
      • Space Group: P 21 21 21
      Unit Cell:
      Length ( Å )Angle ( ˚ )
      a = 94.06α = 90
      b = 109.39β = 90
      c = 151.31γ = 90
      Software Package:
      Software NamePurpose
      SCALAdata scaling
      REFMACrefinement
      PDB_EXTRACTdata extraction
      MAR345data collection
      XDSdata reduction
      CCP4data scaling

      Structure Validation

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      Entry History 

      Deposition Data

      Revision History  (Full details and data files)

      • Version 1.0: 2006-12-12
        Type: Initial release
      • Version 1.1: 2008-05-01
        Changes: Version format compliance
      • Version 1.2: 2011-07-13
        Changes: Version format compliance
      • Version 1.3: 2017-10-18
        Changes: Refinement description
      • Version 2.0: 2020-07-29
        Type: Remediation
        Reason: Carbohydrate remediation
        Changes: Atomic model, Data collection, Derived calculations, Non-polymer description, Structure summary