Protein structure of GR LBDs. Protein structure homology models were created for midshipman GR1 and GR2 LBDs and indicated two substitutions (A/S49 and F/I204) of particular interest. (A) The overall homology model of the GR1 LBD with bound cortisol (red) indicating the position of these two substitutions. Helices are numbered H1 through H12. (B) The substitution at position 49 lengthens helix 3 in GR1 (green) relative to GR2 (blue) as well as changes the structure at this location. (C) Position 204 is found in the ligand-binding pocket, within 4 Å of the putative bound ligand. The change between isoleucine (GR1, green) and phenylalanine (GR2, blue) represents a large change to the shape of the ligand-binding pocket. Model distances between phenylalanine or isoleucine and the ligand (cortisol, red) are indicated.
Arterbery et al. BMC Evolutionary Biology 2011 11:14 doi:10.1186/1471-2148-11-14