Multidomain Assembly of Nuclear Estrogen Receptors: Structural Insights into ER-Positive Breast Cancer Therapeutics

Abstract

Abstract : The major goal of this project is to determine and compare the overall dynamic architectures of both ERs bound to different known DNA response elements (EREs). This study combines small-angle X-ray solution scattering (SAXS) data and computational modeling to address the multimeric assembly of ER DBD-hinge-LBD complexes. To date, we have successfully modeled ER CDE bound to its cognate DNA binding site and generated homogenous ER DBD-hinge-LDB protein samples (ER CDEF) needed for SAXS studies. We have also collected SAXS data on ER CDEF, but not ER CDE. We will continue to generate and compare the ER CDE and CDEF fragments for small angle x-ray scattering (SAXS) analyses of ER multidomain fragments EREs and various peptides to obtain solution structure information. Having worked out the conditions for the expression and purification of ER CDEF, we do not expect difficulties in the expression and purification of ER CDE domain. By integrating SAXS analyses and computational biology, we expect to better understand ER multi-domain assembly mechanisms. It is anticipated that this information will help explain how domain interfaces in ER/ERE complexes modulate ligand-dependent transcriptional activity in response to various SERMs, providing novel structural insights that will facilitate improved targeting of ER-positive breast cancers, especially those that are refractory to current adjuvant therapies.