Crystal structure of the human liver X receptor beta ligand-binding domain in complex with a synthetic agonist

J Mol Biol. 2003 Dec 12;334(5):853-61. doi: 10.1016/j.jmb.2003.10.033.

Abstract

LXRbeta belongs to the nuclear hormone receptor superfamily of ligand-activated transcription factors. Its natural ligands are supposed to be oxidised derivatives of cholesterol. Stimulation of LXRbeta by agonists activates a number of genes that are involved in the regulation of lipid metabolism and cholesterol efflux from cells. Therefore, LXRbeta may represent a novel therapeutic target for the treatment of dyslipidemia and atherosclerosis.Here, we report the X-ray crystal structure of the LXRbeta ligand-binding domain in complex with a synthetic agonist, T-0901317. This compound occupies the ligand-binding pocket of the receptor, forms numerous lipophilic contacts with the protein and one crucial hydrogen bond to His435 and stabilises the agonist conformation of the receptor ligand-binding domain. The recruitment of the AF2-region of the protein is not achieved via direct polar interactions of the ligand with protein side-chains of this helical segment, but rather via few hydrophobic contacts and probably more importantly via indirect effects involving the pre-orientation of side-chains that surround the ligand-binding pocket and form the interface to the AF2-helix. On the basis of these results we propose a binding mode and a mechanism of action for the putative natural ligands, oxidised derivatives of cholesterol.

MeSH terms

  • Amino Acid Sequence
  • Anticholesteremic Agents / pharmacology
  • Cholesterol / metabolism
  • Crystallography, X-Ray
  • DNA-Binding Proteins
  • Humans
  • Hydrocarbons, Fluorinated
  • Ligands
  • Liver X Receptors
  • Models, Molecular
  • Molecular Sequence Data
  • Orphan Nuclear Receptors
  • Protein Conformation
  • Receptors, Cytoplasmic and Nuclear / agonists
  • Receptors, Cytoplasmic and Nuclear / chemistry*
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Sulfonamides

Substances

  • Anticholesteremic Agents
  • DNA-Binding Proteins
  • Hydrocarbons, Fluorinated
  • Ligands
  • Liver X Receptors
  • Orphan Nuclear Receptors
  • Receptors, Cytoplasmic and Nuclear
  • Sulfonamides
  • TO-901317
  • Cholesterol

Associated data

  • PDB/1UPV
  • PDB/1UPW