3TKB

crystal structure of human uracil-DNA glycosylase D183G/K302R mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5 Å
  • R-Value Free: 0.192 
  • R-Value Work: 0.151 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Thermal unfolding studies of cold adapted uracil-DNA N-glycosylase (UNG) from Atlantic cod (Gadus morhua). A comparative study with human UNG.

Assefa, N.G.Niiranen, L.Willassen, N.P.Smalas, A.Moe, E.

(2012) Comp.Biochem.Physiol. B: Biochem.Mol.Biol. 161: 60-68

  • DOI: 10.1016/j.cbpb.2011.09.007

  • PubMed Abstract: 
  • Uracil-DNA N-glycosylase (UNG; EC 3.2.2.27) from Atlantic cod (cUNG) possesses cold adapted features like increased catalytic efficiency and reduced temperature optimum for activity compared to its warm-adapted homologue human UNG (hUNG). Here, we pr ...

    Uracil-DNA N-glycosylase (UNG; EC 3.2.2.27) from Atlantic cod (cUNG) possesses cold adapted features like increased catalytic efficiency and reduced temperature optimum for activity compared to its warm-adapted homologue human UNG (hUNG). Here, we present the first thermal stability analysis of cUNG and hUNG by differential scanning calorimetry (DSC), and the results showed that cUNG is less stable than hUNG and unfolds at a melting temperature (T(m)) 9° lower than its warm-adapted homologue. In addition, an ion-pair (D183-K302) suggested to be crucial for global stability of hUNG was investigated by biochemical characterization and DSC of four mutants (cUNG G183D and cUNG G183D-R302K, hUNG D183G and hUNG D183G-K302R). The hUNG mutants with an expected disruption of the ion-pair showed a slight increase in stability with concomitant reduction in the enzyme activity, while the apparent introduction of the ion-pair in cUNG caused a reduction in the enzyme activity but no increase in stability. Because the mutants did not behave as expected, the phenomenon was further investigated by crystal structure determination. Indeed, the crystal structure of the hUNG D183G-K302R mutant revealed that compensating interactions for the loss of the ion-pair were generated close to and in regions distant from the mutation site. In conclusion, the reduced stability of cUNG supports the suggested requirement of a flexible structure for improved activity at low temperatures. Furthermore, the lack of a direct correlation between enzyme activity and global stability of the mutants supports the significance of distributing locally flexible and/or rigid regions for modulation of enzyme activity.


    Organizational Affiliation

    The Norwegian Structural Biology Center (NorStruct), Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Uracil-DNA glycosylase
A
223Homo sapiensMutation(s): 2 
Gene Names: UNG (DGU, UNG1, UNG15)
EC: 3.2.2.27
Find proteins for P13051 (Homo sapiens)
Go to Gene View: UNG
Go to UniProtKB:  P13051
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
IMD
Query on IMD

Download SDF File 
Download CCD File 
A
IMIDAZOLE
C3 H5 N2
RAXXELZNTBOGNW-UHFFFAOYSA-O
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5 Å
  • R-Value Free: 0.192 
  • R-Value Work: 0.151 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 42.530α = 90.00
b = 39.710β = 97.91
c = 66.730γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
MOLREPphasing
REFMACrefinement
PDB_EXTRACTdata extraction
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-10-12
    Type: Initial release
  • Version 1.1: 2011-12-07
    Type: Database references