1XLS: Crystal Structure Of The Mouse Car/rxr Lbd Heterodimer Bound To Tcpobop And 9cra And A Tif2 Peptide Containg The Third Lxxll Motifs

Constitutive androstane receptor (CAR) induces xenobiotic, bilirubin, and thyroid hormone metabolism as a heterodimer with the retinoid X receptor (RXR). Unlike ligand-dependent nuclear receptors, CAR is constitutively active. Here, we report the heterodimeric structure of the CAR and RXR ligand binding domains (LBDs), which reveals an unusually large dimerization interface and a small CAR ligand binding pocket. Constitutive CAR activity appears to be mediated by the compact nature of the CAR LBD that displays several unique features including a shortened AF2 helix and helix H10, which are linked by a two-turn helix that normally adopts an extended loop in other receptors, and an extended helix H2 that stabilizes the canonical LBD fold by packing tightly against helix H3. These structural observations provide a molecular framework for understanding the atypical transcriptional activation properties of CAR.
PDB ID: 1XLSDownload
MMDB ID: 31117
PDB Deposition Date: 2004/9/30
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 2.96  Å
Source Organism:
Rattus norvegicus
Similar Structures:
Biological Unit for 1XLS: tetrameric; determined by author and by software (PISA)
Molecular Components in 1XLS
Label Count Molecule
Proteins (4 molecules)
Retinoic Acid Receptor Rxr-alpha(Gene symbol: RXRA)
Molecule annotation
Orphan Nuclear Receptor Nr1i3(Gene symbol: Nr1i3)
Molecule annotation
Nuclear Receptor Coactivator 2(Gene symbol: Ncoa2)
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB