Figure 5.

DI pathway (orange surface). The EDO and IMD molecules bind in the DI pathway/interstitial channel that connects the protein surface to the Fe2,3,6,7 and Fe3,4,5,7 FeMo-cofactor faces (orange surface). The CO and S bind in a channel that extends from the DI pathway (purple surface). The α, β, and β′ subunits are shown in green, cyan, and yellow, respectively. Residues lining the pathway are shown in sticks and labeled. The substrates and FeMo-cofactor are displayed as spheres colored by element. The IMD and EDO molecules are superposed in the figure because the binding sites directly overlap.