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 sensors of nitric oxide (NO). We are studying one such signaling pathway from the organism Pseudoalteromonas atlantica, in which an H-NOX protein (PATL1532) is found in the same predicted operon as a histidine kinase (PATL1533). Our findings show that the kinase is capable of autophosphorylation in vitro and H-NOX is found to have an inhibitory effect on kinase activity. Based on the inhibitory effect of various H-NOX ligated and unligated states, we find that H-NOX is a selective NO sensor. The cognate response regulator for the kinase has also been identified, and investigations are underway to elucidate the downstream pathway using gene knockout and differential proteomic strategies?

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

240th National Meeting (2010)

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