4EBD

Conformationally Restrained North-methanocarba-2'-deoxyadenosine Corrects the Error-Prone Nature of Human DNA Polymerase Iota


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.57 Å
  • R-Value Free: 
    0.263 (Depositor), 0.260 (DCC) 
  • R-Value Work: 
    0.206 (Depositor), 0.200 (DCC) 
  • R-Value Observed: 
    0.212 (Depositor) 

Starting Model: experimental
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Ligand Structure Quality Assessment 

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This is version 1.3 of the entry. See complete history


Literature

A Nucleotide-Analogue-Induced Gain of Function Corrects the Error-Prone Nature of Human DNA Polymerase iota.

Ketkar, A.Zafar, M.K.Banerjee, S.Marquez, V.E.Egli, M.Eoff, R.L.

(2012) J Am Chem Soc 134: 10698-10705

  • DOI: https://doi.org/10.1021/ja304176q
  • Primary Citation of Related Structures:  
    4EBC, 4EBD, 4EBE

  • PubMed Abstract: 

    Y-family DNA polymerases participate in replication stress and DNA damage tolerance mechanisms. The properties that allow these enzymes to copy past bulky adducts or distorted template DNA can result in a greater propensity for them to make mistakes. Of the four human Y-family members, human DNA polymerase iota (hpol ι) is the most error-prone. In the current study, we elucidate the molecular basis for improving the fidelity of hpol ι through use of the fixed-conformation nucleotide North-methanocarba-2'-deoxyadenosine triphosphate (N-MC-dATP). Three crystal structures were solved of hpol ι in complex with DNA containing a template 2'-deoxythymidine (dT) paired with an incoming dNTP or modified nucleotide triphosphate. The ternary complex of hpol ι inserting N-MC-dATP opposite dT reveals that the adenine ring is stabilized in the anti orientation about the pseudo-glycosyl torsion angle, which mimics precisely the mutagenic arrangement of dGTP:dT normally preferred by hpol ι. The stabilized anti conformation occurs without notable contacts from the protein but likely results from constraints imposed by the bicyclo[3.1.0]hexane scaffold of the modified nucleotide. Unmodified dATP and South-MC-dATP each adopt syn glycosyl orientations to form Hoogsteen base pairs with dT. The Hoogsteen orientation exhibits weaker base-stacking interactions and is less catalytically favorable than anti N-MC-dATP. Thus, N-MC-dATP corrects the error-prone nature of hpol ι by preventing the Hoogsteen base-pairing mode normally observed for hpol ι-catalyzed insertion of dATP opposite dT. These results provide a previously unrecognized means of altering the efficiency and the fidelity of a human translesion DNA polymerase.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7199, USA.


Macromolecules

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DNA polymerase iota420Homo 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
GTEx:  ENSG00000101751 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9UNA4
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.57 Å
  • R-Value Free:  0.263 (Depositor), 0.260 (DCC) 
  • R-Value Work:  0.206 (Depositor), 0.200 (DCC) 
  • R-Value Observed: 0.212 (Depositor) 
Space Group: P 65 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 97.776α = 90
b = 97.776β = 90
c = 202.739γ = 120
Software Package:
Software NamePurpose
HKL-2000data collection
PHENIXmodel building
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHENIXphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 

Created with Raphaël 2.3.0Worse 01 BetterLigand structure goodness of fit to experimental dataBest fitted 0OJClick on this verticalbar to view details

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-06-13
    Type: Initial release
  • Version 1.1: 2012-07-11
    Changes: Database references
  • Version 1.2: 2017-11-15
    Changes: Advisory, Refinement description
  • Version 1.3: 2023-09-13
    Changes: Advisory, Data collection, Database references, Derived calculations, Refinement description