4GXI

R283K DNA polymerase beta binary complex with a templating 8OG


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.208 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

DNA polymerase minor groove interactions modulate mutagenic bypass of a templating 8-oxoguanine lesion.

Freudenthal, B.D.Beard, W.A.Wilson, S.H.

(2013) Nucleic Acids Res 41: 1848-1858

  • DOI: https://doi.org/10.1093/nar/gks1276
  • Primary Citation of Related Structures:  
    4GXI, 4GXJ, 4GXK

  • PubMed Abstract: 

    A major base lesion resulting from oxidative stress is 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxoG) that has ambiguous coding potential. Error-free DNA synthesis involves 8-oxoG adopting an anti-conformation to base pair with cytosine whereas mutagenic bypass involves 8-oxoG adopting a syn-conformation to base pair with adenine. Left unrepaired the syn-8-oxoG/dAMP base pair results in a G-C to T-A transversion. During base excision repair of this mispair, DNA polymerase (pol) β is confronted with gap filling opposite 8-oxoG. To determine how pol β discriminates between anti- and syn-8-oxoG, we introduced a point mutation (R283K) to alter insertion specificity. Kinetic studies demonstrate that this substitution results in an increased fidelity opposite 8-oxoG. Structural studies with R283K pol β show that the binary DNA complex has 8-oxoG in equilibrium between anti- and syn-forms. Ternary complexes with incoming dCTP resemble the wild-type enzyme, with templating anti-8-oxoG base pairing with incoming cytosine. In contrast to wild-type pol β, the ternary complex of the R283K mutant with an incoming dATP-analogue and templating 8-oxoG resembles a G-A mismatched structure with 8-oxoG adopting an anti-conformation. These results demonstrate that the incoming nucleotide is unable to induce a syn-8-oxoG conformation without minor groove DNA polymerase interactions that influence templating (anti-/syn-equilibrium) of 8-oxoG while modulating fidelity.


  • Organizational Affiliation

    Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, PO Box 12233, Research Triangle Park, NC 27709-2233, USA.


Macromolecules

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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DNA polymerase beta335Homo sapiensMutation(s): 1 
Gene Names: POLB
EC: 2.7.7.7 (PDB Primary Data), 4.2.99 (PDB Primary Data), 4.2.99.18 (UniProt)
UniProt & NIH Common Fund Data Resources
Find proteins for P06746 (Homo sapiens)
Explore P06746 
Go to UniProtKB:  P06746
PHAROS:  P06746
GTEx:  ENSG00000070501 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP06746
Sequence Annotations
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  • Reference Sequence

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Entity ID: 2
MoleculeChains LengthOrganismImage
DNA (5'-D(*CP*CP*GP*AP*CP*(8OG)P*TP*CP*GP*CP*AP*TP*CP*AP*GP*C)-3')B [auth T]16synthetic construct
Sequence Annotations
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  • Reference Sequence

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Entity ID: 3
MoleculeChains LengthOrganismImage
DNA (5'-D(*GP*CP*TP*GP*AP*TP*GP*CP*GP*A)-3')C [auth P]10synthetic construct
Sequence Annotations
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  • Reference Sequence

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Entity ID: 4
MoleculeChains LengthOrganismImage
DNA (5'-D(P*GP*TP*CP*GP*G)-3')5synthetic construct
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.208 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 54.797α = 90
b = 79.258β = 105.62
c = 54.365γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
CNSrefinement
StructureStudiodata collection
HKL-2000data reduction
HKL-2000data scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-01-16
    Type: Initial release
  • Version 1.1: 2013-02-27
    Changes: Database references
  • Version 1.2: 2019-07-17
    Changes: Data collection, Derived calculations, Refinement description
  • Version 1.3: 2023-09-13
    Changes: Data collection, Database references, Derived calculations, Refinement description