NMR Studies of FXR-Prenylflavonoid Complexes

HHMI Summer 2009

Ryan A. MooreDr. Victor HsuAugust 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

http://tennesseeguy.files.wordpress.com/2008/09/hops.jpg

http://www.censcihk.com/big5/admin/web/UploadFile/200922016420253.bmp

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

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

http://www.nassaulibrary.org/hewlett/vitamins.jpg

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)