Nucleotidyl Transfer Mechanism of Mismatched dNTP Incorporation by DNA Polymerase b by Structural and Kinetic Analyses

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.217 

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Mismatched Dntp Incorporation by DNA Polymerase Beta Does not Proceed Via Globally Different Conformational Pathways.

Tang, K.Niebuhr, M.Tung, C.Chan, H.Chou, C.Tsai, M.

(2008) Nucleic Acids Res 36: 2948

  • DOI: https://doi.org/10.1093/nar/gkn138
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Understanding how DNA polymerases control fidelity requires elucidation of the mechanisms of matched and mismatched dNTP incorporations. Little is known about the latter because mismatched complexes do not crystallize readily. In this report, we employed small-angle X-ray scattering (SAXS) and structural modeling to probe the conformations of different intermediate states of mammalian DNA polymerase beta (Pol beta) in its wild-type and an error-prone variant, I260Q. Our structural results indicate that the mismatched ternary complex lies in-between the open and the closed forms, but more closely resembles the open form for WT and the closed form for I260Q. On the basis of molecular modeling, this over-stabilization of mismatched ternary complex of I260Q is likely caused by formation of a hydrogen bonding network between the side chains of Gln(260), Tyr(296), Glu(295) and Arg(258), freeing up Asp(192) to coordinate MgdNTP. These results argue against recent reports suggesting that mismatched dNTP incorporations follow a conformational path distinctly different from that of matched dNTP incorporation, or that its conformational closing is a major contributor to fidelity.

  • Organizational Affiliation

    Departments of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DNA POLYMERSE BETA245Rattus norvegicusMutation(s): 1 
EC: (PDB Primary Data), 4.2.99 (PDB Primary Data)
Find proteins for P06766 (Rattus norvegicus)
Explore P06766 
Go to UniProtKB:  P06766
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP06766
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.217 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 62.862α = 90
b = 119.43β = 90
c = 38.013γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-04-15
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description