TY - JOUR
T1 - Probing conformational changes in the estrogen receptor
T2 - Evidence for a partially unfolded intermediate facilitating ligand binding and release
AU - Gee, A. C.
AU - Katzenellenbogen, J. A.
PY - 2001
Y1 - 2001
N2 - Because the ligand bound to the ligand-binding domain (LBD) of nuclear hormone receptors is completely enveloped by protein, it is thought that the process of ligand binding or unbinding must involve a significant conformational change of this domain. We have used the intrinsic tryptophan fluorescence of the estrogen receptor-α (ERα) or estrogen receptor-β (ERβ) LBD, as well as bis-anilinonaphthalenesulfonate (bis-ANS), a probe for accessible interior regions of protein, to follow the guanidine-hydrochloride (Gua-HCl)-induced unfolding of this domain. In both cases, we find that the ER-LBD unfolding follows a two-phase process. At low Gua-HCl, the ER-LBD undergoes partial unfolding, whereas at high Gua-HCl, this domain undergoes a global unfolding, with bis-ANS binding preferentially to the partially unfolded state. The partially unfolded state of the ERα-LBD induced by denaturant does not bind ligand stably, but it may resemble an intermediate that this domain accesses transiently under native conditions that allow ligands to enter or exit the ligand-binding pocket.
AB - Because the ligand bound to the ligand-binding domain (LBD) of nuclear hormone receptors is completely enveloped by protein, it is thought that the process of ligand binding or unbinding must involve a significant conformational change of this domain. We have used the intrinsic tryptophan fluorescence of the estrogen receptor-α (ERα) or estrogen receptor-β (ERβ) LBD, as well as bis-anilinonaphthalenesulfonate (bis-ANS), a probe for accessible interior regions of protein, to follow the guanidine-hydrochloride (Gua-HCl)-induced unfolding of this domain. In both cases, we find that the ER-LBD unfolding follows a two-phase process. At low Gua-HCl, the ER-LBD undergoes partial unfolding, whereas at high Gua-HCl, this domain undergoes a global unfolding, with bis-ANS binding preferentially to the partially unfolded state. The partially unfolded state of the ERα-LBD induced by denaturant does not bind ligand stably, but it may resemble an intermediate that this domain accesses transiently under native conditions that allow ligands to enter or exit the ligand-binding pocket.
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U2 - 10.1210/mend.15.3.0602
DO - 10.1210/mend.15.3.0602
M3 - Article
C2 - 11222743
AN - SCOPUS:0035102591
SN - 0888-8809
VL - 15
SP - 421
EP - 428
JO - Molecular Endocrinology
JF - Molecular Endocrinology
IS - 3
ER -