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
http://czechabsinthe.files.wordpress.com/2007/04/molecule.jpg
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
http://1in100.files.wordpress.com/2009/06/dna_500.jpg
Research Focus

Xanthohumol
 Found in hops (Humulus lupulus)
 Prenylflavonoid
 Selective bile acid receptor modulator
(SBARM)
http://tennesseeguy.files.wordpress.com/2008/09/hops.jpg
 Ligands with ability to regulate distinct
subset of FXR-specific genes
 Widely researched for medicinal
potential
http://www.censcihk.com/big5/admin/web/UploadFile/200922016420253.bmp
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
http://www.pharmacy.arizona.edu/faculty/yanglab/images/NMRFacility/NMR.JPG
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
http://www.nassaulibrary.org/hewlett/vitamins.jpg
Acknowledgements
Dr. Victor Hsu
Dr. Kevin Ahern
Howard Hughes Medical Institute (HHMI)