Experimental Data Snapshot

  • Resolution: 3.00 Å
  • R-Value Observed: 0.181 

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Crystal structures of human DNA polymerase beta complexed with DNA: implications for catalytic mechanism, processivity, and fidelity

Pelletier, H.Sawaya, M.R.Wolfle, W.Wilson, S.H.Kraut, J.

(1996) Biochemistry 35: 12742-12761

  • DOI: 10.1021/bi952955d
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • Mammalian DNA polymerase beta (pol beta) is a small (39 kDa) DNA gap-filling enzyme that comprises an amino-terminal 8-kDa domain and a carboxy-terminal 31-kDa domain. In the work reported here, crystal structures of human pol beta complexed with blu ...

    Mammalian DNA polymerase beta (pol beta) is a small (39 kDa) DNA gap-filling enzyme that comprises an amino-terminal 8-kDa domain and a carboxy-terminal 31-kDa domain. In the work reported here, crystal structures of human pol beta complexed with blunt-ended segments of DNA show that, although the crystals belong to a different space group, the DNA is nevertheless bound in the pol beta binding channel in the same way as the DNA in previously reported structures of rat pol beta complexed with a template-primer and ddCTP [Pelletier, H., Sawaya, M. R., Kumar, A., Wilson, S. H., & Kraut, J. (1994) Science 264, 1891-1903]. The 8-kDa domain is in one of three previously observed positions relative to the 31-kDa domain, suggesting that the 8-kDa domain may assume only a small number of stable conformations. The thumb subdomain is in a more open position in the human pol beta-DNA binary complex than it is in the rat pol beta-DNA-ddCTP ternary complex, and a closing thumb upon nucleotide binding could represent the rate-limiting conformational change that has been observed in pre-steady-state kinetic studies. Intermolecular contacts between the DNA and the 8-kDa domain of a symmetry-related pol beta molecule reveal a plausible binding site on the 8-kDa domain for the downstream oligonucleotide of a gapped-DNA substrate; in addition to a lysine-rich binding pocket that accommodates a 5'-PO4 end group, the 8-kDa domain also contains a newly discovered helix-hairpin-helix (HhH) motif that binds to DNA in the same way as does a structurally and sequentially homologous HhH motif in the 31-kDa domain. DNA binding by both HhH motifs is facilitated by a metal ion. In that HhH motifs have been identified in other DNA repair enzymes and DNA polymerases, the HhH-DNA interactions observed in pol beta may be applicable to a broad range of DNA binding proteins. The sequence similarity between the HhH motif of endonuclease III from Escherichia coli and the HhH motif of the 8-kDa domain of pol beta is particularly striking in that all of the conserved residues are clustered in one short sequence segment, LPGVGXK, where LPGV corresponds to a type II beta-turn (the hairpin turn), and GXK corresponds to a part of the HhH motif that is proposed to be critical for DNA binding and catalysis for both enzymes. These results suggest that endonuclease III and the 8-kDa domain of pol beta may employ a similar mode of DNA binding and may have similar catalytic mechanisms for their respective DNA lyase activities. A model for productive binding of pol beta to a gapped-DNA substrate requires a 90 degrees bend in the single-stranded template, which could enhance nucleotide selectivity during DNA repair or replication.

    Related Citations: 
    • A Structural Basis for Metal Ion Mutagenicity and Nucleotide Selectivity in Human DNA Polymerase Beta
      Pelletier, H., Sawaya, M.R., Wolfle, W., Wilson, S.H., Kraut, J.
      (1996) Biochemistry 35: 12762
    • Crystal Structures of Human DNA Polymerase Beta Complexed with Nicked and Gapped DNA Substrates
      Sawaya, M.R., Rawson, T., Wilson, S.H., Kraut, J., Pelletier, H.
      () To be published --: --
    • The Role of Thumb Movement and Template Bending in Polymerase Fidelity
      Pelletier, H.
      () To be published --: --
    • Characterization of the Metal Ion-Binding HHH Motifs in Human DNA Polymerase Beta by X-Ray Structural Analysis
      Pelletier, H., Sawaya, M.R.
      (1996) Biochemistry 35: 12778
    • Polymerase Structures and Mechanism
      Pelletier, H.
      (1994) Science 266: 2025
    • Structures of Ternary Complexes of Rat DNA Polymerase Beta, a DNA Template- Primer, and ddCTP
      Pelletier, H., Sawaya, M.R., Kumar, A., Wilson, S.H., Kraut, J.
      (1994) Science 264: 1891
    • Crystal Structure of Rat DNA Polymerase Beta: Evidence for a Common Polymerase Mechanism
      Sawaya, M.R., Pelletier, H., Kumar, A., Wilson, S.H., Kraut, J.
      (1994) Science 264: 1930

    Organizational Affiliation

    Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla 92093-0506, USA.


Find similar proteins by: Sequence  |  Structure

Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
PROTEIN (DNA POLYMERASE BETA (E.C. sapiensMutation(s): 0 
Gene Names: POLB
EC: (UniProt), 4.2.99 (UniProt)
Find proteins for P06746 (Homo sapiens)
Explore P06746 
Go to UniProtKB:  P06746
NIH Common Fund Data Resources
PHAROS  P06746
Protein Feature View
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  • Reference Sequence
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Entity ID: 1
DNA (5'-D(*CP*AP*TP*TP*AP*GP*A)-3')T7N/A
  • Find similar nucleic acids by: Sequence   |   Structure
Entity ID: 2
DNA (5'-D(*TP*CP*TP*AP*AP*TP*G)-3')P7N/A
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
Query on SO4

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O4 S
 Ligand Interaction
Query on NA

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 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Resolution: 3.00 Å
  • R-Value Observed: 0.181 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 180.827α = 90
b = 57.645β = 90
c = 48.167γ = 90
Software Package:
Software NamePurpose
SDMSdata reduction
SDMSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1996-11-15
    Type: Initial release
  • Version 1.1: 2008-05-22
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance