Animal stomachs are hostile environments, yet some bacteria can thrive there. Linked to several medical conditions, from ulcers to gastric cancers, the stomach-infecting bacterium Helicobacter pylori (pictured with its close relative, H. felis) has special adaptations for survive the stomach acids. In particular, it relies on two key enzymes, proteins which facilitate chemical reactions, to supply it with energy and keep its pH relatively neutral. Both these enzymes must bind to nickel ions to be active, so the bacteria need to accumulate large concentrations of nickel. Such high levels would be toxic without specific nickel-binding proteins, Hpn and Hpn-2, found only in gastric Helicobacter species. These proteins safely store the nickel away, organise its release when needed, and are essential for successful colonisation of the stomach. As they don’t naturally occur in humans, targeting these nickel-handling proteins is a promising avenue for treating H. pylori infections.
Written by Emmanuelle Briolat
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