TABLE 1.

Estrogen binding activity of wild-type and mutant receptors^a

Receptor	Kd (nM)
Wild-type mERα	0.33
I362A-L376A-V380A	0.28
I362D	0.49
L376D	0.86
V380D	0.90
K366L	0.31
K366D	0.33

^aExtracts prepared from transiently transfected COS-1 cells were analyzed for ligand binding activity. The dissociation constant (K_d) for ligand binding for each mutant was determined by Scatchard analysis.