Hydrogen peroxide sensing in Bacillus subtilis: it is all about the (metallo)regulator

P>Microorganisms have evolved an impressive array of mechanisms to adapt to stress induced by reactive oxygen species (ROS) of virtually any kind. One such regulator is Bacillus subtilis PerR, a member of the ubiquitous Fur (Ferric uptake regulator) family of metalloregulatory repressors, which senses hydrogen peroxide. In this issue of Molecular Microbiology, Duarte, Latour and colleagues report the structure of the Mn(II)-bound form of PerR, a first for the Fe/Mn-selective members of the Fur family. The structure reveals how a regulatory metal drives a quaternary structural switch that allosterically activates the PerR dimer to bind its DNA operator, while also providing detailed insight into the mechanism of metal-catalysed ligand oxidation and transcriptional derepression that uniquely characterizes PerR.