FIG. 2.

Structure of the active site of NDO, showing the Rieske [2Fe-2S] center and mononuclear iron in adjacent α subunits with their coordinating amino acids (shown in white ball-and-stick format). Also shown are Asp-205, an amino acid important for efficient electron transfer between the two redox centers, and the amino acids that were targets for site-directed mutagenesis in this study. RasMol (version 2.6) was used to generate the view of the active site.