Protein-protein interactions within peroxiredoxin systems.

Peroxiredoxin systems in plants were demonstrated involved in crucial roles related to reactive oxygenated species (ROS) metabolism and the linked cell signalling to ROS. Peroxiredoxins function as peroxidasic systems that combine at least a reactivating reductant agent like thioredoxins, and sometimes glutaredoxins and glutathion. In the past three years a number of peroxiredoxin structures were solved by crystallography in different experimental crystallisation conditions. The structures have revealed a significant propensity of peroxiredoxins for oligomerism that was confirmed by biophysical studies in solution using NMR and other methods as analytical ultra-centrifugation. These studies showed that quaternary structures of peroxiredoxins involve specific protein-protein interaction interfaces that rely upon the peroxiredoxin types and/or their redox conditions. The protein-protein interactions with the reactivating redoxins essentially lead to transient unstable complexes. We review herein the different protein-protein interactions characterized or deduced from those reports.