Structural alterations and stabilization of @entity95 uterine @entity172 receptors by natural XXXX .

@entity172 @entity95 @entity8037 @entity7224 @entity969 @entity4663 @entity11667
Estrogenic regulation of gene expression involves interaction of the hormone with its receptors, which undergo structural and conformational changes to interact with specific DNA sequences. @entity7224 , @entity11667 , and @entity8037 , are ubiquitous cellular components. We studied the effects of these @entity4663 on @entity95 uterine @entity172 receptors by @entity969 gradient centrifugation and ligand dissociation kinetics. The native 7S receptor converted to a 9S-10S form in the presence of 100 microM @entity11667 or @entity8037 . Higher concentrations caused precipitation of the receptor. This precipitation was reduced by RNase treatment of the receptor. RNase-treated receptors sedimented at 4S and 7S regions of @entity969 gradient. The dissociation rate constant (k) of the 4S receptor is 2.8 X 10(-3) min-1 in the presence of 1 mM @entity11667 , compared to a control value of 7.7 X 10(-3) min-1. Similar effects were observed with @entity7224 and @entity8037 . The dissociation of the RNase-treated 7S receptor was biphasic, with about 50% of the receptors dissociating at a faster rate (k1 = 40 X 10(-3) min-1) than the other half (k2 = 7.4 X 10(-3) min-1). @entity11667 (1 mM) caused a 2-fold reduction in k2, whereas k1 was not affected. This study shows that @entity4663 affect the structural organization and ligand dissociation kinetics of @entity172 -receptor complexes.
