Prokaryotes employ two-component signaling pathways to detect and respond to environmental stimuli. Recently, in some prokaryotes, H-NOX (Heme-Nitric oxide/OXygen binding domain) proteins have been implicated in two-component signaling as nitric oxide sensors. We are studying one such pathway from Pseudoalteromonas atlantica, in which an H-NOX gene is found in the same operon as a histidine kinase. We show that the kinase is capable of autophosphorylation in vitro and H-NOX is found to inhibit kinase activity. Based on this we also find that H-NOX is a selective NO sensor. The cognate response regulator has also been identified and phosphotransfer established. Additionally, we have used H-NOX in a reporter system to show that H-NOX/NO can affect the activity of EnvZ kinase, which it does not associate with in its natural environment. This is indicative of the role of H-NOX as an NO sensing module in bacteria, with potential applications in synthetic biology.

Characterization of an H-NOX regulated two-component signaling pathway in<i> Pseudoalteromonas atlantica</i>

243rd National Meeting (2012)

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Characterization of an H-NOX regulated two-component signaling pathway in Pseudoalteromonas atlantica