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Updated: Aug 20, 2026

Computational Prediction of Amino Acid Preferences of Potentially Multispecific Peptide-Binding Domains Involved in Protein-Protein Interactions
06:50

Computational Prediction of Amino Acid Preferences of Potentially Multispecific Peptide-Binding Domains Involved in Protein-Protein Interactions

Published on: January 26, 2024

Amino acids important for ligand specificity of the human constitutive androstane receptor

Johanna Jyrkkärinne1, Björn Windshügel, Janne Mäkinen

  • 1Department of Pharmaceutics, University of Kuopio, P. O. Box 1627, FIN-70211 Kuopio, Finland.

The Journal of Biological Chemistry
|December 2, 2004
PubMed

Insights

Researchers identified key amino acids in the human constitutive androstane receptor (CAR) ligand-binding domain. These residues influence CAR

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Pharmacology

Background:

  • The human constitutive androstane receptor (CAR, NR1I3) regulates key metabolic enzymes and transporters.
  • Understanding CAR ligand specificity is crucial due to its role in drug metabolism and toxicity.
  • Lack of structural data and species differences complicate CAR ligand specificity studies.

Purpose of the Study:

  • To elucidate the molecular determinants of human CAR ligand specificity.
  • To identify specific amino acid residues within the CAR ligand-binding domain (LBD) responsible for basal activity, ligand selectivity, and species differences.

Main Methods:

  • Homology modeling of the human CAR LBD.
  • Molecular dynamics simulations with known CAR modulators.
  • Site-directed mutagenesis of 22 LBD residues.
  • Mammalian co-transfection and yeast two-hybrid assays to assess protein function.

Main Results:

  • Identified residues in helices 3, 5, 11, and 12 contributing to high basal CAR activity.
  • Discovered unique residues in helices 3, 5, and 7 controlling selectivity for CAR activators and inhibitors.
  • Pinpointed a single residue (Phe243 in helix 7) responsible for human/mouse species differences in CAR response to 17alpha-ethynyl-3,17beta-estradiol.

Conclusions:

  • Specific amino acid residues within the CAR LBD are critical for its basal activity, ligand selectivity, and interspecies differences.
  • This study provides a molecular basis for understanding CAR-ligand interactions and designing CAR modulators.
  • The identified residues offer targets for future drug development and toxicological assessments.

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