Yang Liping, Broderick David, Jiang Yuan, Hsu Victor, Maier Claudia S
Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA.
Department of Statistics, Oregon State University, Corvallis, OR 97331, USA.
Biochim Biophys Acta. 2014 Sep;1844(9):1684-93. doi: 10.1016/j.bbapap.2014.06.007. Epub 2014 Jun 18.
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.
法尼酯X受体（FXR）是转录因子核受体超家族的成员，在胆汁酸、脂质和葡萄糖代谢的调节中起关键作用。FXR的调节功能由配体结合后配体结合域（LBD）的构象变化所控制。尽管FXR是一个经过大量研究的潜在治疗靶点，但只有有限数量的FXR激动剂复合物成功结晶并随后获得了高分辨率结构。目前尚无任何FXR拮抗剂复合物的结构信息公开。因此，我们探索了使用酰胺氢/氘交换（HDX）结合质谱来表征配体结合后FXR-LBD中的构象变化。获得了三种FXR配体化学类型的配体特异性氘掺入谱：GW4064，一种合成的非甾体高亲和力激动剂；胆汁酸鹅去氧胆酸（CDCA），FXR的内源性低亲和力激动剂；以及Z-古甾酮（GG），一种甾体化学类型的体外拮抗剂。对其配体结合的FXR-LBD复合物HDX谱的比较揭示了GG独特的相互作用模式。讨论了FXR-LBD-拮抗剂相互作用构象特征。
