1R0O: Crystal Structure Of The Heterodimeric Ecdysone Receptor Dna-Binding Complex

Ecdysteroids initiate molting and metamorphosis in insects via a heterodimeric receptor consisting of the ecdysone receptor (EcR) and ultraspiracle (USP). The EcR-USP heterodimer preferentially mediates transcription through highly degenerate pseudo-palindromic response elements, resembling inverted repeats of 5'-AGGTCA-3' separated by 1 bp (IR-1). The requirement for a heterodimeric arrangement of EcR-USP subunits to bind to a symmetric DNA is unusual within the nuclear receptor superfamily. We describe the 2.24 A structure of the EcR-USP DNA-binding domain (DBD) heterodimer bound to an idealized IR-1 element. EcR and USP use similar surfaces, and rely on the deformed minor groove of the DNA to establish protein-protein contacts. As retinoid X receptor (RXR) is the mammalian homolog of USP, we also solved the 2.60 A crystal structure of the EcR-RXR DBD heterodimer on IR-1 and found the dimerization and DNA-binding interfaces to be the same as in the EcR-USP complex. Sequence alignments indicate that the EcR-RXR heterodimer is an important model for understanding how the FXR-RXR heterodimer binds to IR-1 sites.
PDB ID: 1R0ODownload
MMDB ID: 51076
PDB Deposition Date: 2003/9/22
Updated in MMDB: 2012/12
Experimental Method:
x-ray diffraction
Resolution: 2.24  Å
Source Organism:
synthetic construct
Similar Structures:
Biological Unit for 1R0O: tetrameric; determined by author
Molecular Components in 1R0O
Label Count Molecule
Proteins (2 molecules)
Ultraspiracle Protein(Gene symbol: usp)
Molecule annotation
Ecdysone Receptor(Gene symbol: EcR)
Molecule annotation
Nucleotides(2 molecules)
Ecdysone Response Element
Molecule annotation
Ecdysone Response Element
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB