Utilizing Natural and Engineered Peroxiredoxins As Intracellular Peroxide Reporters

It is increasingly apparent that nature evolved peroxiredoxins not only as H₂O₂ scavengers but also as highly sensitive H₂O₂ sensors and signal transducers. Here we ask whether the H₂O₂ sensing role of Prx can be exploited to develop probes that allow to monitor intracellular H₂O₂ levels with unprecedented sensitivity. Indeed, simple gel shift assays visualizing the oxidation of endogenous 2-Cys peroxiredoxins have already been used to detect subtle changes in intracellular H₂O₂ concentration. The challenge however is to create a genetically encoded probe that offers real-time measurements of H₂O₂ levels in intact cells via the Prx oxidation state. We discuss potential design strategies for Prx-based probes based on either the redox-sensitive fluorophore roGFP or the conformation-sensitive fluorophore cpYFP. Furthermore, we outline the structural and chemical complexities which need to be addressed when using Prx as a sensing moiety for H₂O₂ probes. We suggest experimental strategies to investigate the influence of these complexities on probe behavior. In doing so, we hope to stimulate the development of Prx-based probes which may spearhead the further study of cellular H₂O₂ homeostasis and Prx signaling.