4M9N

DNA Polymerase Beta E295K Soaked with dATP


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.275 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.192 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The E295K Cancer Variant of Human Polymerase beta Favors the Mismatch Conformational Pathway during Nucleotide Selection.

Eckenroth, B.E.Towle-Weicksel, J.B.Sweasy, J.B.Doublie, S.

(2013) J.Biol.Chem. 288: 34850-34860

  • DOI: 10.1074/jbc.M113.510891
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • DNA polymerase β (pol β) is responsible for gap filling synthesis during repair of damaged DNA as part of the base excision repair pathway. Human pol β mutations were recently identified in a high percentage (∼30%) of tumors. Characterization of spec ...

    DNA polymerase β (pol β) is responsible for gap filling synthesis during repair of damaged DNA as part of the base excision repair pathway. Human pol β mutations were recently identified in a high percentage (∼30%) of tumors. Characterization of specific cancer variants is particularly useful to further the understanding of the general mechanism of pol β while providing context to disease contribution. We showed that expression of the carcinoma variant E295K induces cellular transformation. The poor polymerase activity exhibited by the variant was hypothesized to be caused by the destabilization of proper active site assembly by the glutamate to lysine mutation. Here, we show that this variant exhibits an unusual preference for binding dCTP opposite a templating adenine over the cognate dTTP. Biochemical studies indicate that the noncognate competes with the cognate nucleotide for binding to the polymerase active site with the noncognate incorporation a function of higher affinity and not increased activity. In the crystal structure of the variant bound to dA:dCTP, the fingers domain closes around the mismatched base pair. Nucleotide incorporation is hindered because key residues in the polymerase active site are not properly positioned for nucleotidyl transfer. In contrast to the noncognate dCTP, neither the cognate dTTP nor its nonhydrolyzable analog induced fingers closure, as isomorphous difference Fourier maps show that the cognate nucleotides are bound to the open state of the polymerase. Comparison with published structures provides insight into the structural rearrangements within pol β that occur during the process of nucleotide discrimination.


    Organizational Affiliation

    From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405 and.




Macromolecules

Find similar proteins by: Sequence  |  Structure


Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
DNA polymerase beta
A
335Homo sapiensMutation(s): 1 
Gene Names: POLB
EC: 2.7.7.7, 4.2.99.-
Find proteins for P06746 (Homo sapiens)
Go to Gene View: POLB
Go to UniProtKB:  P06746
Entity ID: 2
MoleculeChainsLengthOrganism
DNA Template StrandT16N/A
Entity ID: 3
MoleculeChainsLengthOrganism
DNA Primer StrandP10N/A
Entity ID: 4
MoleculeChainsLengthOrganism
DNA Downstream StrandD5N/A
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
DTP
Query on DTP

Download SDF File 
Download CCD File 
A
2'-DEOXYADENOSINE 5'-TRIPHOSPHATE
C10 H16 N5 O12 P3
SUYVUBYJARFZHO-RRKCRQDMSA-N
 Ligand Interaction
NA
Query on NA

Download SDF File 
Download CCD File 
A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
MG
Query on MG

Download SDF File 
Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.275 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.192 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 54.523α = 90.00
b = 79.215β = 106.24
c = 54.685γ = 90.00
Software Package:
Software NamePurpose
PHENIXrefinement
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-10-16
    Type: Initial release
  • Version 1.1: 2013-10-30
    Type: Database references
  • Version 1.2: 2013-12-18
    Type: Database references