3GV8

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.218 

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:  

  • 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 ...

    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: Sequence  |  Structure


Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
DNA polymerase iota
B
420Homo sapiensMutation(s): 0 
Gene Names: POLI (RAD30B)
EC: 2.7.7.7
Find proteins for Q9UNA4 (Homo sapiens)
Go to Gene View: POLI
Go to UniProtKB:  Q9UNA4
Entity ID: 2
MoleculeChainsLengthOrganism
5'-D(*AP*TP*GP*GP*GP*TP*CP*CP*T)-3'T9N/A
Entity ID: 3
MoleculeChainsLengthOrganism
5'-D(*AP*GP*GP*AP*CP*CP*C)-3'P7N/A
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MG
Query on MG

Download SDF File 
Download CCD File 
B
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
DGT
Query on DGT

Download SDF File 
Download CCD File 
B
2'-DEOXYGUANOSINE-5'-TRIPHOSPHATE
C10 H16 N5 O13 P3
HAAZLUGHYHWQIW-KVQBGUIXSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.218 
  • Space Group: P 65 2 2
Unit Cell:
Length (Å)Angle (°)
a = 98.070α = 90.00
b = 98.070β = 90.00
c = 203.380γ = 120.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
REFMACrefinement
PDB_EXTRACTdata extraction
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

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