X-Ray Crystal Structure of the Ancestral 3-Ketosteroid Receptor–Progesterone–Mifepristone Complex Shows Mifepristone Bound at the Coactivator Binding Interface
Figure 6
Global alignment of progesterone-bound steroid receptors.
A cartoon representation of the ancSR2–progesterone–mifepristone (slate blue), ancSR2–progesterone (orange, PDB accession code: 4FN9), and progesterone receptor–progesterone (purple, PDB accession code 1A28) complexes overlay with high overall structural similarity. B. Ligand adopts an identical position and conformation in two progesterone-bound receptor structures. The ancSR2–progesterone–mifepristone (ligand – slate blue, receptor – light blue) and progesterone receptor–progesterone (ligand – magenta, receptor – light pink, PDB accession code 1A28) structures show identical positioning and conformation of the ligand within the ligand binding pocket. Progesterone makes hydrogen bonds with Arg82 and Thr210 in both structures (dashed red lines).