title: Conformational dynamics of human FXR-LBD ligand interactions studied by hydrogen/deuterium exchange mass spectrometry: insights into the antagonism of the hypolipidemic agent Z-guggulsterone.
abstract: Farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily of transcription factors that plays a key role in the regulation of bile acids, lipid and glucose metabolisms. The regulative function of FXR is governed by conformational changes of the ligand binding domain (LBD) upon ligand binding. Although FXR is a highly researched potential therapeutic target, only a limited number of FXR-agonist complexes have been successfully crystallized and subsequently yielded high resolution structures. There is currently no structural information of any FXR-antagonist complexes publically available. We therefore explored the use of amide hydrogen/deuterium exchange (HDX) coupled with mass spectrometry for characterizing conformational changes in the FXR-LBD upon ligand binding. Ligand-specific deuterium incorporation profiles were obtained for three FXR ligand chemotypes: GW4064, a synthetic non-steroidal high affinity agonist; the bile acid chenodeoxycholic acid (CDCA), the endogenous low affinity agonist of FXR; and Z-guggulsterone (GG), an in vitro antagonist of the steroid chemotype. A comparison of the HDX profiles of their ligand-bound FXR-LBD complexes revealed a unique mode of interaction for GG. The conformational features of the FXR-LBD-antagonist interaction are discussed.
authors: Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA.
authors: Liping
authors: L
authors: Yang
authors: Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA.
authors: David
authors: D
authors: Broderick
authors: Department of Statistics, Oregon State University, Corvallis, OR 97331, USA.
authors: Yuan
authors: Y
authors: Jiang
authors: Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA.
authors: Victor
authors: V
authors: Hsu
authors: Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA. Electronic address: claudia.maier@oregonstate.edu.
authors: Claudia S
authors: CS
authors: Maier
mesh_terms: D000595:Amino Acid Sequence; D002635:Chenodeoxycholic Acid / Q000737:chemistry; D041961:Deuterium Exchange Measurement; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D006801:Humans; D000960:Hypolipidemic Agents / Q000737:chemistry*; D007555:Isoxazoles / Q000737:chemistry; D008024:Ligands; D013058:Mass Spectrometry / Q000379:methods; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D011282:Pregnenediones / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000819:agonists / Q000037:antagonists & inhibitors / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D000099150:Receptor, Farnesoid X-Activated
chemical_list: D002635:Chenodeoxycholic Acid; D000960:Hypolipidemic Agents; D007555:Isoxazoles; D008024:Ligands; D011282:Pregnenediones; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D000099150:Receptor, Farnesoid X-Activated; C023617:pregna-4,17-diene-3,16-dione; C412815:GW 4064
keywords: Conformational dynamics; Farnesoid X receptor; Guggulsterone; Hydrogen/deuterium exchange; Ligand interaction; Mass spectrometry