4FS1

Base pairing mechanism of N2,3-ethenoguanine with dTTP by human polymerase iota


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.215 
  • R-Value Observed: 0.218 

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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Basis of Miscoding of the DNA Adduct N2,3-Ethenoguanine by Human Y-family DNA Polymerases.

Zhao, L.Pence, M.G.Christov, P.P.Wawrzak, Z.Choi, J.Y.Rizzo, C.J.Egli, M.Guengerich, F.P.

(2012) J Biol Chem 287: 35516-35526

  • DOI: 10.1074/jbc.M112.403253
  • Primary Citation of Related Structures:  
    4FS1, 4FS2

  • PubMed Abstract: 
  • N(2),3-Ethenoguanine (N(2),3-εG) is one of the exocyclic DNA adducts produced by endogenous processes (e.g. lipid peroxidation) and exposure to bioactivated vinyl monomers such as vinyl chloride, which is a known human carcinogen. Existing studies exploring the miscoding potential of this lesion are quite indirect because of the lability of the glycosidic bond ...

    N(2),3-Ethenoguanine (N(2),3-εG) is one of the exocyclic DNA adducts produced by endogenous processes (e.g. lipid peroxidation) and exposure to bioactivated vinyl monomers such as vinyl chloride, which is a known human carcinogen. Existing studies exploring the miscoding potential of this lesion are quite indirect because of the lability of the glycosidic bond. We utilized a 2'-fluoro isostere approach to stabilize this lesion and synthesized oligonucleotides containing 2'-fluoro-N(2),3-ε-2'-deoxyarabinoguanosine to investigate the miscoding potential of N(2),3-εG by Y-family human DNA polymerases (pols). In primer extension assays, pol η and pol κ replicated through N(2),3-εG, whereas pol ι and REV1 yielded only 1-base incorporation. Steady-state kinetics revealed that dCTP incorporation is preferred opposite N(2),3-εG with relative efficiencies in the order of pol κ > REV1 > pol η ≈ pol ι, and dTTP misincorporation is the major miscoding event by all four Y-family human DNA pols. Pol ι had the highest dTTP misincorporation frequency (0.71) followed by pol η (0.63). REV1 misincorporated dTTP and dGTP with much lower frequencies. Crystal structures of pol ι with N(2),3-εG paired to dCTP and dTTP revealed Hoogsteen-like base pairing mechanisms. Two hydrogen bonds were observed in the N(2),3-εG:dCTP base pair, whereas only one appears to be present in the case of the N(2),3-εG:dTTP pair. Base pairing mechanisms derived from the crystal structures explain the slightly favored dCTP insertion for pol ι in steady-state kinetic analysis. Taken together, these results provide a basis for the mutagenic potential of N(2),3-εG.


    Organizational Affiliation

    Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA.



Macromolecules

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
DNA polymerase iotaC [auth A]420Homo sapiensMutation(s): 0 
Gene Names: POLIRAD30B
EC: 2.7.7.7
UniProt & NIH Common Fund Data Resources
Find proteins for Q9UNA4 (Homo sapiens)
Explore Q9UNA4 
Go to UniProtKB:  Q9UNA4
PHAROS:  Q9UNA4
Protein Feature View
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  • Reference Sequence

Find similar nucleic acids by:  Sequence   |   3D Structure  

Entity ID: 1
MoleculeChainsLengthOrganismImage
DNA 5'-D(*TP*CP*TP*(EFG)P*GP*GP*GP*TP*CP*CP*TP*AP*GP*GP*AP*CP*CP*(DOC))-3'A [auth B], B [auth C]18synthetic construct
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
TTP (Subject of Investigation/LOI)
Query on TTP

Download Ideal Coordinates CCD File 
H [auth A]THYMIDINE-5'-TRIPHOSPHATE
C10 H17 N2 O14 P3
NHVNXKFIZYSCEB-XLPZGREQSA-N
 Ligand Interaction
MG
Query on MG

Download Ideal Coordinates CCD File 
D [auth A], E [auth A], F [auth A]MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
NA
Query on NA

Download Ideal Coordinates CCD File 
G [auth A]SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.215 
  • R-Value Observed: 0.218 
  • Space Group: P 65 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 97.47α = 90
b = 97.47β = 90
c = 203.541γ = 120
Software Package:
Software NamePurpose
EMBLdata collection
MOLREPphasing
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment  



Entry History 

Deposition Data

  • Deposited Date: 2012-06-26 
  • Released Date: 2012-08-29 
  • Deposition Author(s): Zhao, L.

Revision History  (Full details and data files)

  • Version 1.0: 2012-08-29
    Type: Initial release
  • Version 1.1: 2012-09-12
    Changes: Database references
  • Version 1.2: 2012-10-31
    Changes: Database references