NMR Studies of FXR-Prenylflavonoid Complexes HHMI Summer 2009 Ryan A. Moore Dr. Victor Hsu August 25, 2009
Nuclear Receptors Family of protein receptors activated by presence of steroids and hormones Work in conjunction with other receptors to regulate cell development and metabolism maintain homeostasis In presence of ligand, have ability to bind to DNA to regulate expression
Research Focus The farnesoid X receptor (FXR) Expressed at high levels in liver and intestine Bile acid-activated nuclear receptor Contributes to bile acid synthesis and lipid metabolism Important regulator of metabolic homeostasis
tennesseeguy.files.wordpress.com/2008/09/hops.jpg Research Focus Xanthohumol Found in hops (Humulus lupulus) Prenylflavonoid Selective bile acid receptor modulator (SBARM) Ligands with ability to regulate distinct subset of FXR-specific genes Widely researched for medicinal potential
Hypothesis Binding prenylflavonoid-type ligands to FXR results in unique structural dynamics which will yield new complexes that regulate activation of FXR target genes.
Project Overview Primary approach: Fluorescent spectroscopy to observe binding Buffer solution containing protein is titrated with natural ligand Compare to same solution titrated with xanthohumol
Continuing Research Next step: Label receptor with nitrogen isotope Use nuclear magnetic resonance (NMR) spectroscopy & hydrogen/deuterium exchange mass spectroscopy
Continuing Research From this: Determine structure of binding site Model how FXR binds with xanthohumol and other prenylflavonoids Observe amide nitrogen and proton chemical shifts and determine if resulting structures are ligand specific
Potential Future Applications Prenylflavonoids have not been extensively studied as specific targets for FXR receptors Pharmaceuticals containing prenylflavonoids New treatment options for metabolic diseases Heart disease Type-2 diabetes Atherosclerosis Dietary supplements
Acknowledgements Dr. Victor Hsu Dr. Kevin Ahern Howard Hughes Medical Institute (HHMI)