Moonlighting by different stressors: crystal structure of the chaperone species of a 2-Cys peroxiredoxin
Saccoccia F, Di Micco P, Boumis G, Brunori M, Koutris I, Miele AE, Morea V, Sriratana P, Williams DL, Bellelli A, Angelucci F
Structure (2012) 20(3): 429-39.
2-Cys peroxiredoxins (Prxs) play two different roles depending on the physiological status of the cell. They are thioredoxin-dependent peroxidases under low oxidative stress and ATP-independent chaper- ones upon exposure to high peroxide concentra- tions. These alternative functions have been associ- ated with changes in the oligomerization state from low-(LMW) to high-molecular-weight (HMW) species.
Here we present the structures of Schistosoma mansoni PrxI in both states: the LMW decamer and the HMW 20-mer formed by two stacked decamers. The latter is the structure of a 2-Cys Prx chaperonic form. Comparison of the structures sheds light on the mechanism by which chemical stressors, such as high H2O2 concentration and acidic pH, are sensed and translated into a functional switch in this protein family.
We also propose a model to account for the in vivo formation of long filaments of stacked Prx rings.