1N39

Structural and biochemical exploration of a critical amino acid in human 8-oxoguanine glycosylase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.242 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural and biochemical exploration of a critical amino acid in human 8-oxoguanine glycosylase

Norman, D.P.Chung, S.J.Verdine, G.L.

(2003) Biochemistry 42: 1564-1572

  • DOI: 10.1021/bi026823d
  • Primary Citation of Related Structures:  1N3A, 1N3C

  • PubMed Abstract: 
  • Members of the HhH-GPD superfamily of DNA glycosylases are responsible for the recognition and removal of damaged nucleobases from DNA. The hallmark of these proteins is a motif comprising a helix-hairpin-helix followed by a Gly/Pro-rich loop and ter ...

    Members of the HhH-GPD superfamily of DNA glycosylases are responsible for the recognition and removal of damaged nucleobases from DNA. The hallmark of these proteins is a motif comprising a helix-hairpin-helix followed by a Gly/Pro-rich loop and terminating in an invariant, catalytically essential aspartic acid residue. In this study, we have probed the role of this Asp in human 8-oxoguanine DNA glycosylase (hOgg1) by mutating it to Asn (D268N), Glu (D268E), and Gln (D268Q). We show that this aspartate plays a dual role, acting both as an N-terminal alpha-helix cap and as a critical residue for catalysis of both base excision and DNA strand cleavage by hOgg1. Mutation of this residue to asparagine, another helix-capping residue, preserves stability of the protein while drastically reducing enzymatic activity. A crystal structure of this mutant is the first to reveal the active site nucleophile Lys249 in the presence of lesion-containing DNA; this structure offers a tantalizing suggestion that base excision may occur by cleavage of the glycosidic bond and then attachment of Lys249. Mutation of the aspartic acid to glutamine and glutamic acid destabilizes the protein fold to a significant extent but, surprisingly, preserves catalytic activity. Crystal structures of these mutants complexed with an unreactive abasic site in DNA reveal these residues to adopt a sterically disfavored helix-capping conformation.


    Organizational Affiliation

    Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure


Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
N-glycosylase/DNA lyase
A
317Homo sapiensGene Names: OGG1 (MMH, MUTM, OGH1)
EC: 3.2.2.-, 4.2.99.18
Find proteins for O15527 (Homo sapiens)
Go to Gene View: OGG1
Go to UniProtKB:  O15527
Entity ID: 1
MoleculeChainsLengthOrganism
DNA complement strandB15N/A
Entity ID: 2
MoleculeChainsLengthOrganism
DNA inhibitor strandC15N/A
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
C
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
3DR
Query on 3DR
C
DNA LINKINGC5 H11 O6 P

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Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.242 
  • Space Group: P 65 2 2
Unit Cell:
Length (Å)Angle (°)
a = 92.366α = 90.00
b = 92.366β = 90.00
c = 211.277γ = 120.00
Software Package:
Software NamePurpose
HKL-2000data collection
CNSphasing
CNSrefinement
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-03-04
    Type: Initial release
  • Version 1.1: 2008-04-28
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance