His laboratory’s work focuses on characterizing the structure and function of the terminal steps of heme biosynthesis in both eucaryotes and procaryotes. This work has involved the functional characterization of the terminal three enzymes and the identification of bacterial-specific enzymes at the penultimate and antepenultimate steps. This has included the identification of unique [2Fe-2S] clusters in bacterial ferrochelatase, one of which is similar to the [2Fe-2S] cluster of animal ferrochelatases. He has also characterized the molecular basis of some human porphyrias including the creation of a knockin mouse to recreate the molecular basis of South African variegate porphyria, an inherited human disease for which he first identified the causative mutation.