3GV5

Human DNA polymerase iota in complex with T template DNA and incoming ddADP


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.206 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural basis of error-prone replication and stalling at a thymine base by human DNA polymerase iota

Kirouac, K.N.Ling, H.

(2009) EMBO J 28: 1644-1654

  • DOI: 10.1038/emboj.2009.122
  • Primary Citation of Related Structures:  
    3GV5, 3GV7, 3GV8

  • PubMed Abstract: 
  • Human DNA polymerase iota (pol iota) is a unique member of Y-family polymerases, which preferentially misincorporates nucleotides opposite thymines (T) and halts replication at T bases. The structural basis of the high error rates remains elusive. We pre ...

    Human DNA polymerase iota (pol iota) is a unique member of Y-family polymerases, which preferentially misincorporates nucleotides opposite thymines (T) and halts replication at T bases. The structural basis of the high error rates remains elusive. We present three crystal structures of pol complexed with DNA containing a thymine base, paired with correct or incorrect incoming nucleotides. A narrowed active site supports a pyrimidine to pyrimidine mismatch and excludes Watson-Crick base pairing by pol. The template thymine remains in an anti conformation irrespective of incoming nucleotides. Incoming ddATP adopts a syn conformation with reduced base stacking, whereas incorrect dGTP and dTTP maintain anti conformations with normal base stacking. Further stabilization of dGTP by H-bonding with Gln59 of the finger domain explains the preferential T to G mismatch. A template 'U-turn' is stabilized by pol and the methyl group of the thymine template, revealing the structural basis of T stalling. Our structural and domain-swapping experiments indicate that the finger domain is responsible for pol's high error rates on pyrimidines and determines the incorporation specificity.


    Organizational Affiliation

    Department of Biochemistry, University of Western Ontario, London, Ontario, Canada.



Macromolecules

Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
DNA polymerase iota BD420Homo sapiensMutation(s): 0 
Gene Names: POLIRAD30B
EC: 2.7.7.7
Find proteins for Q9UNA4 (Homo sapiens)
Explore Q9UNA4 
Go to UniProtKB:  Q9UNA4
NIH Common Fund Data Resources
PHAROS:  Q9UNA4
Protein Feature View
Expand
  • Reference Sequence
  • Find similar nucleic acids by:  Sequence   |   Structure
  • Entity ID: 2
    MoleculeChainsLengthOrganismImage
    5'-D(*GP*TP*GP*GP*AP*TP*GP*AP*G)-3'E, P9N/A
    • Find similar nucleic acids by:  Sequence   |   Structure
    • Entity ID: 3
      MoleculeChainsLengthOrganismImage
      5'-D(P*CP*AP*TP*TP*CP*TP*CP*AP*TP*CP*CP*AP*C)-3'F, T13N/A
      Experimental Data & Validation

      Experimental Data

      • Method: X-RAY DIFFRACTION
      • Resolution: 2.00 Å
      • R-Value Free: 0.253 
      • R-Value Work: 0.205 
      • R-Value Observed: 0.206 
      • Space Group: C 1 2 1
      Unit Cell:
      Length ( Å )Angle ( ˚ )
      a = 140.16α = 90
      b = 71.75β = 112.53
      c = 127.42γ = 90
      Software Package:
      Software NamePurpose
      DENZOdata reduction
      SCALEPACKdata scaling
      REFMACrefinement
      PDB_EXTRACTdata extraction

      Structure Validation

      View Full Validation Report



      Entry History 

      Deposition Data

      Revision History 

      • Version 1.0: 2009-06-02
        Type: Initial release
      • Version 1.1: 2011-07-13
        Changes: Advisory, Version format compliance
      • Version 1.2: 2017-11-01
        Changes: Refinement description