Figure 4.

Metal–metal distances of six QM/MM models (QM region: 181 atoms) calculated using the BS7-235 solution compared to the X-ray structure. The green and blue ellipsoids highlight the Fe₂–Fe₃ and Fe₆–Fe₇ distances that are strongly affected by the redox state. The red ellipsoid highlights the change in the Fe₄–Fe₅ distance with the bridging XO₃ ligand. The metal–metal distances of the crystal structure are the average of the two cofactors found in the 5N6Y crystal structure. All distances are in angstroms.