Figure 1: Canonical domain structure of a steroid receptor. A) SRs contain an amino-terminal domain (NTD), DNA-binding domain (DBD), hinge region and ligand binding domain (LBD). B) The LBD (light blue) is comprised of 12 helices, layered to form two functional sites: the ligand binding pocket, a hydrophobic cavity where the steroid ligand (orange) binds; and AF-2, the surface for coregulator (shown in green) interactions. The NTD contains a ligand-independent activation function 1 domain. (Crystal structure adapted from PDB 5UFS).