Thioredoxins and Glutaredoxins. Functions and Metal Ion Interactions
Thioredoxins and glutaredoxins represent the major cellular systems for the reduction of protein disulfides and protein de-glutathionylation, respectively. These two systems are involved in many aspects of human health, for instance as electron donors of metabolic enzymes and by controlling and maintaining the cellular redox state. The members of this protein family are characterized by a common structural motif, the thioredoxin fold. This basic architecture consists of a central four-stranded β-sheet surrounded by three α-helices. During the past few years accumulating evidence suggests a close relationship between these redoxins, most of all the glutaredoxins, and the cellular iron pool. Today we know that the thioredoxin fold cannot only be utilized for specific protein-protein interactions but also for interactions with metals, for instance iron-sulfur centers. Within this chapter, we summarize these recent findings and discuss the potential physiological implications of these metal interactions.