1JK2

Zif268 D20A mutant bound to the GCT DNA site


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.230 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Rearrangement of side-chains in a Zif268 mutant highlights the complexities of zinc finger-DNA recognition.

Miller, J.C.Pabo, C.O.

(2001) J.Mol.Biol. 313: 309-315

  • DOI: 10.1006/jmbi.2001.4975
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Structural and biochemical studies of Cys(2)His(2) zinc finger proteins initially led several groups to propose a "recognition code" involving a simple set of rules relating key amino acid residues in the zinc finger protein to bases in its DNA site. ...

    Structural and biochemical studies of Cys(2)His(2) zinc finger proteins initially led several groups to propose a "recognition code" involving a simple set of rules relating key amino acid residues in the zinc finger protein to bases in its DNA site. One recent study from our group, involving geometric analysis of protein-DNA interactions, has discussed limitations of this idea and has shown how the spatial relationship between the polypeptide backbone and the DNA helps to determine what contacts are possible at any given position in a protein-DNA complex. Here we report a study of a zinc finger variant that highlights yet another source of complexity inherent in protein-DNA recognition. In particular, we find that mutations can cause key side-chains to rearrange at the protein-DNA interface without fundamental changes in the spatial relationship between the polypeptide backbone and the DNA. This is clear from a simple analysis of the binding site preferences and co-crystal structures for the Asp20-->Ala point mutant of Zif268. This point mutation in finger one changes the specificity of the protein from GCG TGG GCG to GCG TGG GC(G/T), and we have solved crystal structures of the D20A mutant bound to both types of sites. The structure of the D20A mutant bound to the GCG site reveals that contacts from key residues in the recognition helix are coupled in complex ways. The structure of the complex with the GCT site also shows an important new water molecule at the protein-DNA interface. These side-chain/side-chain interactions, and resultant changes in hydration at the interface, affect binding specificity in ways that cannot be predicted either from a simple recognition code or from analysis of spatial relationships at the protein-DNA interface. Accurate computer modeling of protein-DNA interfaces remains a challenging problem and will require systematic strategies for modeling side-chain rearrangements and change in hydration.


    Related Citations: 
    • Zif268 Protein-DNA Complex Refined at 1.6 A: A Model System for Understanding Zinc Finger-DNA Interactions
      Elrod-Erickson, M.,Rould, M.A.,Nekludova, L.,Pabo, C.O.
      (1996) Structure 4: 1171
    • Binding Studies with Mutants of Zif268. Contribution of Individual Side Chains to Binding Affinity and Specificity in the Zif268 Zinc Finger-DNA Complex
      Elrod-Erickson, M.,Pabo, C.O.
      (1999) J.Biol.Chem. 274: 19281


    Organizational Affiliation

    Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure


Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
ZIF268
A
90Mus musculusMutation(s): 1 
Gene Names: Egr1 (Egr-1, Krox-24)
Find proteins for P08046 (Mus musculus)
Go to UniProtKB:  P08046
Entity ID: 1
MoleculeChainsLengthOrganism
5'-D(*AP*GP*CP*GP*TP*GP*GP*GP*CP*TP*G)-3'B11N/A
Entity ID: 2
MoleculeChainsLengthOrganism
5'-D(*TP*CP*AP*GP*CP*CP*CP*AP*CP*GP*C)-3'C11N/A
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.230 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 43.600α = 90.00
b = 56.050β = 90.00
c = 131.560γ = 90.00
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORphasing
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-10-19
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance