Crystal structure of the heterodimeric complex of LXRalpha and RXRbeta ligand-binding domains in a fully agonistic conformation

EMBO J. 2003 Sep 15;22(18):4625-33. doi: 10.1093/emboj/cdg456.


The nuclear receptor heterodimers of liver X receptor (LXR) and retinoid X receptor (RXR) are key transcriptional regulators of genes involved in lipid homeostasis and inflammation. We report the crystal structure of the ligand-binding domains (LBDs) of LXRalpha and RXRbeta complexed to the synthetic LXR agonist T-0901317 and the RXR agonist methoprene acid (Protein Data Base entry 1UHL). Both LBDs are in agonist conformation with GRIP-1 peptides bound at the coactivator binding sites. T-0901317 occupies the center of the LXR ligand-binding pocket and its hydroxyl head group interacts with H421 and W443, residues identified by mutational analysis as critical for ligand-induced transcriptional activation by T-0901317 and various endogenous oxysterols. The topography of the pocket suggests a common anchoring of these oxysterols via their 22-, 24- or 27-hydroxyl group to H421 and W443. Polyunsaturated fatty acids act as LXR antagonists and an E267A mutation was found to enhance their transcriptional inhibition. The present structure provides a powerful tool for the design of novel modulators that can be used to characterize further the physiological functions of the LXR-RXR heterodimer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Binding Sites
  • Cloning, Molecular
  • Crystallography, X-Ray
  • DNA Primers
  • DNA-Binding Proteins / chemistry*
  • Dimerization
  • Escherichia coli / genetics
  • Ligands
  • Liver X Receptors
  • Models, Molecular
  • Orphan Nuclear Receptors
  • Peptide Fragments / chemistry
  • Polymerase Chain Reaction
  • Protein Conformation
  • Receptors, Cytoplasmic and Nuclear / chemistry*
  • Recombinant Proteins / chemistry


  • DNA Primers
  • DNA-Binding Proteins
  • Ligands
  • Liver X Receptors
  • Orphan Nuclear Receptors
  • Peptide Fragments
  • Receptors, Cytoplasmic and Nuclear
  • Recombinant Proteins

Associated data

  • PDB/1UHL