An examination of coexistence of the minor component in the re-refined reduced form by Fo-Fc map calculation. The Fo-Fc maps for the re-refined fully reduced form in the the following regions including residues 48 to 55 (A), residues 380 to 385 (B), and the hydroxyfarnesyl ethyl group of heme a (C), each giving positive (green) and negative (red) residual densities and the oxidized (magenta)- and reduced (cyan)-type structures. Electron density cages of the Fo-Fc maps were drawn at 3.0 σ. In panel B, representative positive density cages on the oxidized-type model are indicated by green arrows, and representative negative density cages on the reduced-type model are indicated by red arrows. However, panel A does not show any representative electron density cage, and panel C provides two representative positive cages indicated by green arrows. This figure represents the results for monomer A.