Fig. 4. Ligand-binding pocket volume doubles in the repressive conformation.

Ligand-binding pocket volumes (red surfaces) were calculated and displayed using the program CASTp. Ligands were removed from the structures for all calculations. Helix 12 was removed from the repressive conformation structure (PDB 6ONI) to assess the relative pocket volume to the active conformation structures. Calculations for the active conformation structure (PDB 6ONJ), which displays density for the Ω-loop region, were performed with and without the Ω-loop region for comparison to the repressive conformation structure, which lacks the Ω-loop region.