Examples of heme proteins with multiple apo structures. (A) RMSD distribution of apo structure of three heme protein chains, 1KBIA, 1N45A, and 1N5UA. The 28 apo structures of 1N5UA form two clusters (red ovals). (B) Structure of 1N5UA with one heme and five myristic acid molecules (MYR, red spacefill). (C) Structure of 1AO6A with no ligands. (D) Structure of 3CX9A with five myristic acid molecules (MYR, red spacefill) and one LPX ligand (orange spacefill).