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Environmental Estrogens and Breast Cancer Therapeutics: Characterization of the Diverse Ligand Binding Properties of the Estrogen ReceptorEPA Grant Number: U915389
Title: Environmental Estrogens and Breast Cancer Therapeutics: Characterization of the Diverse Ligand Binding Properties of the Estrogen Receptor
Investigators: Warn, Dana
Institution: University of Colorado at Boulder
EPA Project Officer: Just, Theodore J.
Project Period: August 24, 1998 through August 1, 2001
Project Amount: $81,034
RFA: STAR Graduate Fellowships (1998) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Biology/Life Sciences , Fellowship - Biochemistry
The objective of this research project is to develop a structural understanding of how the estrogen receptor (ER) binds several environmental estrogens, estrogens, and antiestrogens. We are developing biophysical methods needed to address the following key questions:
1. How ligand dependent are the conformational changes that occur on ligand binding?
2. Do these compounds have the same ligand contacts?
3. Can the diverse responses of the ER to ligands be correlated with conformational changes that occur upon ligand binding?
4. Can this method be used to develop a reliable assay to predict the estrogenic behavior of chemicals before they are released into the environment?
In the context of the available structural data, I am using multidimensional nuclear magnetic resonance (NMR) spectroscopy studies of complexes of these compounds with the ligand binding domain (LBD) of the ER to investigate changes that occur on ligand binding. My strategy of chemical shift mapping by NMR works as follows: (1) the ER-LBD is prepared 15N isotopically labeled by expression in Escherichia coli in minimal media; (2) 15N-1H correlation spectra are taken of different ligand-ER-LBD complexes; and (3) 15N-1H chemical shift changes are monitored. Because chemical shifts are sensitive to changes in the local chemical environment and in conformation, monitoring chemical shift changes allows an assessment of the ligand dependency of conformational changes and rapid analysis of many complexes.