4U6P

Structural mechanism of error-free bypass of major benzo[a]pyrene adduct by human polymerase kappa


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.593 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.200 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Structure and mechanism of error-free replication past the major benzo[a]pyrene adduct by human DNA polymerase kappa.

Jha, V.Bian, C.Xing, G.Ling, H.

(2016) Nucleic Acids Res. 44: 4957-4967

  • DOI: 10.1093/nar/gkw204
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Benzo[a]pyrene (BP) is a well-known and frequently encountered carcinogen which generates a bulky DNA adduct (+)-trans-10S-BP-N(2)-dG (BP-dG) in cells. DNA polymerase kappa (polκ) is the only known Y-family polymerase that bypasses BP-dG accurately a ...

    Benzo[a]pyrene (BP) is a well-known and frequently encountered carcinogen which generates a bulky DNA adduct (+)-trans-10S-BP-N(2)-dG (BP-dG) in cells. DNA polymerase kappa (polκ) is the only known Y-family polymerase that bypasses BP-dG accurately and thus protects cells from genotoxic BP. Here, we report the structures of human polκ in complex with DNA containing either a normal guanine (G) base or a BP-dG adduct at the active site and a correct deoxycytidine. The structures and supporting biochemical data reveal a unique mechanism for accurate replication by translesion synthesis past the major bulky adduct. The active site of polκ opens at the minor groove side of the DNA substrate to accommodate the bulky BP-dG that is attached there. More importantly, polκ stabilizes the lesion DNA substrate in the same active conformation as for regular B-form DNA substrates and the bulky BPDE ring in a 5' end pointing conformation. The BP-dG adducted DNA substrate maintains a Watson-Crick (BP-dG:dC) base pair within the active site, governing correct nucleotide insertion opposite the bulky adduct. In addition, polκ's unique N-clasp domain supports the open conformation of the enzyme and the extended conformation of the single-stranded template to allow bypass of the bulky lesion. This work illustrates the first molecular mechanism for how a bulky major adduct is replicated accurately without strand misalignment and mis-insertion.


    Organizational Affiliation

    Department of Biochemistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, N6A 5C1, Canada.




Macromolecules

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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
DNA polymerase kappa
A, B
526Homo sapiensMutation(s): 0 
Gene Names: POLK (DINB1)
EC: 2.7.7.7
Find proteins for Q9UBT6 (Homo sapiens)
Go to Gene View: POLK
Go to UniProtKB:  Q9UBT6
Entity ID: 2
MoleculeChainsLengthOrganism
DNA (5'-D(P*GP*CP*GP*GP*AP*TP*CP*AP*C)-3')C,P9unidentified
Entity ID: 3
MoleculeChainsLengthOrganism
DNA (5'-D(*TP*AP*TP*GP*GP*TP*GP*AP*TP*CP*CP*GP*C)-3')D,T13unidentified
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
DCT
Query on DCT

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Download CCD File 
A, B
2',3'-DIDEOXYCYTIDINE 5'-TRIPHOSPHATE
C9 H16 N3 O12 P3
ARLKCWCREKRROD-POYBYMJQSA-N
 Ligand Interaction
MG
Query on MG

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Download CCD File 
A, B
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
PGE
Query on PGE

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Download CCD File 
B
TRIETHYLENE GLYCOL
C6 H14 O4
ZIBGPFATKBEMQZ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.593 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.200 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 66.150α = 90.00
b = 129.286β = 90.00
c = 167.713γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
PHENIXrefinement
SCALAdata scaling
PHENIXphasing

Structure Validation

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Entry History 

Deposition Data

  • Deposited Date: 2014-07-29 
  • Released Date: 2016-01-27 
  • Deposition Author(s): Jha, V.K., Ling, H.

Revision History 

  • Version 1.0: 2016-01-27
    Type: Initial release
  • Version 1.1: 2016-03-23
    Type: Derived calculations
  • Version 1.2: 2016-04-13
    Type: Database references
  • Version 1.3: 2016-06-15
    Type: Database references