1M08

Crystal structure of the unbound nuclease domain of ColE7


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.187 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The Crystal Structure of the Nuclease Domain of Colicin E7 Suggests a Mechanism for Binding to Double-stranded DNA by the H-N-H Endonucleases

Cheng, Y.S.Hsia, K.C.Doudeva, L.G.Chak, K.F.Yuan, H.S.

(2002) J.mol.biol. 324: 227-236


  • PubMed Abstract: 
  • The bacterial toxin ColE7 contains an H-N-H endonuclease domain (nuclease ColE7) that digests cellular DNA or RNA non-specifically in target cells, leading to cell death. In the host cell, protein Im7 forms a complex with ColE7 to inhibit its nucleas ...

    The bacterial toxin ColE7 contains an H-N-H endonuclease domain (nuclease ColE7) that digests cellular DNA or RNA non-specifically in target cells, leading to cell death. In the host cell, protein Im7 forms a complex with ColE7 to inhibit its nuclease activity. Here, we present the crystal structure of the unbound nuclease ColE7 at a resolution of 2.1A. Structural comparison between the unbound and bound nuclease ColE7 in complex with Im7, suggests that Im7 is not an allosteric inhibitor that induces backbone conformational changes in nuclease ColE7, but rather one that inhibits by blocking the substrate-binding site. There were two nuclease ColE7 molecules in the P1 unit cell in crystals and they appeared as a dimer related to each other by a non-crystallographic dyad symmetry. Gel-filtration and cross-linking experiments confirmed that nuclease ColE7 indeed formed dimers in solution and that the dimeric conformation was more favored in the presence of double-stranded DNA. Structural comparison of nuclease ColE7 with the His-Cys box homing endonuclease I-PpoI further demonstrated that H-N-H motifs in dimeric nuclease ColE7 were oriented in a manner very similar to that of the betabetaalpha-fold of the active sites found in dimeric I-PpoI. A mechanism for the binding of double-stranded DNA by dimeric H-N-H nuclease ColE7 is suggested.


    Related Citations: 
    • The crystal structure of the DNase domain of colicin E7 in complex with its inhibitor Im7 protein
      Ko, T.P.,Liao, C.C.,Ku, W.Y.,Chak, K.F.,Yuan, H.S.
      (1999) Structure 7: 91


    Organizational Affiliation

    Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, ROC.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Colicin E7
A, B
131Escherichia coliMutation(s): 0 
Gene Names: colE7 (cea)
EC: 3.1.-.-
Find proteins for Q47112 (Escherichia coli)
Go to UniProtKB:  Q47112
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PO4
Query on PO4

Download SDF File 
Download CCD File 
A, B
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
ZN
Query on ZN

Download SDF File 
Download CCD File 
A, B
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.187 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 37.700α = 96.80
b = 39.200β = 103.90
c = 53.200γ = 91.40
Software Package:
Software NamePurpose
SCALEPACKdata scaling
CNSrefinement
CNSphasing
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-12-11
    Type: Initial release
  • Version 1.1: 2008-04-28
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Source and taxonomy, Version format compliance