Iron‐containing metalloenzymes are found throughout the natural world and are vital catalysts in many crucial metabolic and biosynthetic biological pathways. In nature, the major classes of metallo‐heme‐proteins are the monooxygenases, containing a protoporphyrin IX center, the catalases and the peroxidases. The cytochromes P450 (P450s) are a superfamily of heme‐containing, structurally and functionally diverse enzymes that are ubiquitous to most biochemical systems; as such they have attracted interest of many researchers. The huge array of often evolutionarily unrelated proteins that fall into this super class of enzymes means that it is more useful to subdivide nonheme iron enzymes into classes based on the ligands that coordinate their iron cores. The largest of these classes belongs to a group of nonheme iron dioxygenases which have a structural motif that coordinates the iron through two histidine and one aspartate amino acid creating a facial 2‐His‐1‐Asp ligand system.