4EOT

Crystal structure of the MafA homodimer bound to the consensus MARE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.855 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.221 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

A Novel DNA Binding Mechanism for maf Basic Region-Leucine Zipper Factors Inferred from a MafA-DNA Complex Structure and Binding Specificities.

Lu, X.Guanga, G.P.Wan, C.Rose, R.B.

(2012) Biochemistry 51: 9706-9717

  • DOI: 10.1021/bi301248j

  • PubMed Abstract: 
  • MafA is a proto-oncoprotein and is critical for insulin gene expression in pancreatic β-cells. Maf proteins belong to the AP1 superfamily of basic region-leucine zipper (bZIP) transcription factors. Residues in the basic helix and an ancillary N-term ...

    MafA is a proto-oncoprotein and is critical for insulin gene expression in pancreatic β-cells. Maf proteins belong to the AP1 superfamily of basic region-leucine zipper (bZIP) transcription factors. Residues in the basic helix and an ancillary N-terminal domain, the Extended Homology Region (EHR), endow maf proteins with unique DNA binding properties: binding a 13 bp consensus site consisting of a core AP1 site (TGACTCA) flanked by TGC sequences and binding DNA stably as monomers. To further characterize maf DNA binding, we determined the structure of a MafA-DNA complex. MafA forms base-specific hydrogen bonds with the flanking G(-5)C(-4) and central C(0)/G(0) bases, but not with the core-TGA bases. However, in vitro binding studies utilizing a pulse-chase electrophoretic mobility shift assay protocol revealed that mutating either the core-TGA or flanking-TGC bases dramatically increases the binding off rate. Comparing the known maf structures, we propose that DNA binding specificity results from positioning the basic helix through unique phosphate contacts. The EHR does not contact DNA directly but stabilizes DNA binding by contacting the basic helix. Collectively, these results suggest a novel multistep DNA binding process involving a conformational change from contacting the core-TGA to contacting the flanking-TGC bases.


    Organizational Affiliation

    Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure


Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Transcription factor MafA
A, B
95Homo sapiensMutation(s): 0 
Gene Names: MAFA
Find proteins for Q8NHW3 (Homo sapiens)
Go to Gene View: MAFA
Go to UniProtKB:  Q8NHW3
Entity ID: 2
MoleculeChainsLengthOrganism
5'-D(*CP*CP*GP*GP*TP*GP*CP*TP*GP*AP*GP*TP*CP*AP*GP*CP*AP*GP*G)-3'C19N/A
Entity ID: 3
MoleculeChainsLengthOrganism
5'-D(*CP*CP*CP*TP*GP*CP*TP*GP*AP*CP*TP*CP*AP*GP*CP*AP*CP*CP*G)-3'D19N/A
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.855 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.221 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 116.100α = 90.00
b = 116.100β = 90.00
c = 85.080γ = 120.00
Software Package:
Software NamePurpose
XDSdata scaling
PHENIXrefinement
XDSdata reduction
PHASERphasing
XSCALEdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-11-28
    Type: Initial release
  • Version 1.1: 2012-12-26
    Type: Database references