6BOW

Human APE1 substrate complex with an T/T mismatch adjacent the THF


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.59 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.214 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Apurinic/apyrimidinic (AP) endonuclease 1 processing of AP sites with 5' mismatches.

Fairlamb, M.S.Whitaker, A.M.Freudenthal, B.D.

(2018) Acta Crystallogr D Struct Biol 74: 760-768

  • DOI: https://doi.org/10.1107/S2059798318003340
  • Primary Citation of Related Structures:  
    6BOQ, 6BOR, 6BOS, 6BOT, 6BOU, 6BOV, 6BOW

  • PubMed Abstract: 

    Despite the DNA duplex being central to biological functions, many intricacies of this molecule, including the dynamic nature of mismatched base pairing, are still unknown. The unique conformations adopted by DNA mismatches can provide insight into the forces at play between nucleotides. Moreover, DNA-binding proteins apply their own individualized steric and electrochemical influences on the nucleotides that they interact with, further altering base-pairing conformations. Here, seven X-ray crystallographic structures of the human nuclease apurinic/apyrimidinic (AP) endonuclease 1 (APE1) in complex with its substrate target flanked by a 5' mismatch are reported. The structures reveal how APE1 influences the conformations of a variety of different mismatched base pairs. Purine-purine mismatches containing a guanine are stabilized by a rotation of the guanine residue about the N-glycosidic bond to utilize the Hoogsteen edge for hydrogen bonding. Interestingly, no rotation of adenine, the other purine, is observed. Mismatches involving both purine and pyrimidine bases adopt wobble conformations to accommodate the mismatch. Pyrimidine-pyrimidine mismatches also wobble; however, the smaller profile of a pyrimidine base results in a gap between the Watson-Crick faces that is reduced by a C1'-C1' compression. These results advance our understanding of mismatched base pairing and the influence of a bound protein.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66016, USA.


Macromolecules

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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DNA-(apurinic or apyrimidinic site) lyase
A, B
318Homo sapiensMutation(s): 1 
Gene Names: APEX1APEAPE1APEXAPXHAP1REF1
EC: 3.1 (PDB Primary Data), 4.2.99.18 (PDB Primary Data), 3.1.21 (UniProt), 3.1.11.2 (UniProt)
UniProt & NIH Common Fund Data Resources
Find proteins for P27695 (Homo sapiens)
Explore P27695 
Go to UniProtKB:  P27695
PHAROS:  P27695
GTEx:  ENSG00000100823 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP27695
Sequence Annotations
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  • Reference Sequence

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Entity ID: 2
MoleculeChains LengthOrganismImage
21-mer DNAC [auth P]21synthetic construct
Sequence Annotations
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  • Reference Sequence

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Entity ID: 3
MoleculeChains LengthOrganismImage
21-mer DNAD [auth V]21synthetic construct
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.59 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.214 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 44.259α = 83.31
b = 61.333β = 78.28
c = 73.119γ = 86.96
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data scaling
PDB_EXTRACTdata extraction
HKL-2000data reduction

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of Environmental Health Sciences (NIH/NIEHS)United StatesES024431

Revision History  (Full details and data files)

  • Version 1.0: 2018-08-15
    Type: Initial release
  • Version 1.1: 2019-02-20
    Changes: Author supporting evidence, Data collection
  • Version 1.2: 2019-12-18
    Changes: Author supporting evidence
  • Version 1.3: 2023-10-04
    Changes: Data collection, Database references, Refinement description