The Cu(II) Reductase RclA Protects against the Combination of Hypochlorous Acid and Intracellular Copper.

Enterobacteria, including , bloom to high levels in the gut during inflammation and strongly contribute to the pathology of inflammatory bowel diseases. To survive in the inflamed gut, must tolerate high levels of antimicrobial compounds produced by the immune system, including toxic metals like copper and reactive chlorine oxidants such as hypochlorous acid (HOCl). Here, we show that extracellular copper is a potent detoxifier of HOCl and that the widely conserved bacterial HOCl resistance enzyme RclA, which catalyzes the reduction of copper(II) to copper(I), specifically protects against damage caused by the combination of HOCl and intracellular copper.