Bacterial protein structure tied to NO resistance

In a paper published Thursday in Nature Communications, researchers identified a mechanism by which some bacterial pathogens regulate gene expression to survive the toxic effects of nitric oxide produced during a host's immune response to infection.

A team at the University of East Anglia and Institut de Biologie Structurale identified the crystal structure of bacterial transcriptional repressor NsrR. The protein contains an iron-sulfur cluster that reacts with nitric oxide, thereby initiating the NO response pathway. By determining the structure of NsrR both bound to the iron-sulfur cluster and unbound, the researchers identified the mechanism by which the cluster is released from NsrR when the protein senses NO. Once the cluster is lost, the protein can no longer bind to DNA and act as a repressor, and genes that encode NO-detoxifying enzymes are switched on. ...