Involvement of peroxiredoxin bcp2 in oxidative stress in Sulfolobus solfataricus.

Reactive oxygen species (ROS) such as superoxide and hydroxyl radicals, hydrogen peroxide, are potent oxidant capable of damaging all cellular components including DNA, proteins and membrane lipids. In order to protect against the toxicity of ROS, organisms are equipped with an array of defence mechanisms. Among these, peroxiredoxins (Prxs) (1), a family of thiol-specific antioxidant proteins, have received significant attention in the last years. Prxs exert their protective antioxidant role in cells through their peroxidase activity, whereby hydrogen peroxide, peroxynitrite and a wide range of organic hydroperoxides are reduced and detoxified. These enzymes have been identified in each domain of life: Eucarya (2), Bacteria (3)and Archaea (4). Prxs use a redox-active cysteine to reduce peroxides and can be divided into two groups, the 1-Cys and 2-Cys Prxs, based on the cysteinyl residues involved in the catalysis. [i]S.[/i] [i]solfataricus[/i], is an aerobic hyperthermophilic Archaea whose genome has been sequenced. The genome analysis shows the presence of four putative Prxs (Bcp1, Bcp2, Bcp3, Bcp4) whose physiological roles in the oxidative stress are underway. We report the involvement of [i]bcp2[/i] gene in oxidative stress, the characterization of the recombinant protein rSsBcp2, its capability to scavenge H2O2 and to protect DNA against the cleavage caused from thiol-mixed –function oxidation (MFO) system.