New research shows how a protein is consumed and then reconstituted during the production of lipoic acid, a compound required by our bodies to convert energy from food into a form that can be used by our cells. The lipoyl synthase enzyme (LipA) removes two hydrogen atoms from an inert carbon chain and replaces them with sulfur atoms from one of its own iron-sulfur clusters to create lipoic acid, rendering itself inactive in the process. The new research from Penn State University, which will be published in the journal Science on October 20, 2017, shows that another protein, an iron-sulfur cluster carrier called NfuA, replaces the destroyed iron-sulfur cluster in LipA, allowing it to continue producing lipoic acid. The results also could help scientists to understand why humans with defects in the iron-sulfur carrier gene—a fatal condition—have deficiencies of lipoic acid.