Crystal Structure of 3-methyladenine DNA glycosylase I (TAG)

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.163 

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DNA damage recognition and repair by 3-methyladenine DNA glycosylase I (TAG).

Metz, A.H.Hollis, T.Eichman, B.F.

(2007) EMBO J 26: 2411-2420

  • DOI: https://doi.org/10.1038/sj.emboj.7601649
  • Primary Citation of Related Structures:  
    2OFI, 2OFK

  • PubMed Abstract: 

    DNA glycosylases help maintain the genome by excising chemically modified bases from DNA. Escherichia coli 3-methyladenine DNA glycosylase I (TAG) specifically catalyzes the removal of the cytotoxic lesion 3-methyladenine (3mA). The molecular basis for the enzymatic recognition and removal of 3mA from DNA is currently a matter of speculation, in part owing to the lack of a structure of a 3mA-specific glycosylase bound to damaged DNA. Here, high-resolution crystal structures of Salmonella typhi TAG in the unliganded form and in a ternary product complex with abasic DNA and 3mA nucleobase are presented. Despite its structural similarity to the helix-hairpin-helix superfamily of DNA glycosylases, TAG has evolved a modified strategy for engaging damaged DNA. In contrast to other glycosylase-DNA structures, the abasic ribose is not flipped into the TAG active site. This is the first structural demonstration that conformational relaxation must occur in the DNA upon base hydrolysis. Together with mutational studies of TAG enzymatic activity, these data provide a model for the specific recognition and hydrolysis of 3mA from DNA.

  • Organizational Affiliation

    Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
3-methyladenine DNA glycosylase I, constitutive
A, B
183Salmonella enterica subsp. enterica serovar TyphiMutation(s): 0 
Gene Names: 
Find proteins for Q8Z2A5 (Salmonella typhi)
Explore Q8Z2A5 
Go to UniProtKB:  Q8Z2A5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8Z2A5
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on PGE

Download Ideal Coordinates CCD File 
D [auth A]
E [auth A]
F [auth A]
G [auth A]
I [auth B]
D [auth A],
E [auth A],
F [auth A],
G [auth A],
I [auth B],
J [auth B],
K [auth B],
L [auth B]
C6 H14 O4
Query on ZN

Download Ideal Coordinates CCD File 
C [auth A],
H [auth B]
Experimental Data & Validation

Experimental Data

  • Resolution: 1.50 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.163 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.455α = 90
b = 63.681β = 106.94
c = 62.127γ = 90
Software Package:
Software NamePurpose
SERGUIdata collection
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-05-15
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance