Nitric oxide regulated two-component signaling in Pseudoalteromonas atlantica

Bacterial Haemoprotein Sensors of NO

“…Based on homology to sGC and genomic association with signalling proteins, it was hypothesized that bacterial H-NOX proteins would also serve as sensors of NO (or possibly O 2 in the case of obligate aerobic organisms), regulating signal transduction of the associated signalling proteins. Many subsequent studies have confirmed the role of the interaction of H-NOX with NO in modulating the activities of these proteins (Arora & Boon, 2012; Henares, Higgins, & Boon, 2012; Henares, Xu, & Boon, 2013; Liu et al, 2012; Muralidharan & Boon, 2012); these studies will be described later in this review (see Section 6).…”

“…Many bacterial H-NOX domains have now been cloned, expressed, purified, and spectroscopically characterized (Arora & Boon, 2012; Boon et al, 2006; Dai, Farquhar, Arora, & Boon, 2012; Henares et al, 2012; Karow et al, 2004; Liu et al, 2012; Ma, Sayed, Beuve, & van den Akker, 2007; Mukhopadyay, Sudasinghe, Schaub, & Yukl, 2016; Price, Chao, & Marletta, 2007; Tsai, Berka, Martin, & Olson, 2012; Tsai et al, 2010; Wang et al, 2010; Wu, Liu, Berka, & Tsai, 2015). UV/vis spectroscopy, paired with resonance Raman (rR) spectroscopy, has demonstrated that ferrous H-NOX domains from facultative aerobes form high-spin 5-coordinate Fe(II)-unligated complexes (Boon et al, 2006; Karow et al, 2004).…”

Nitric Oxide Regulation of H-NOX Signaling Pathways in Bacteria

“…29 In the absence of Pa H-NOX, purified Pa HaHK displays autophosphorylation activity in an ATP- and time-dependent manner. Further, Pa HaHK activity is inhibited by all forms of Pa H-NOX [Fe(III), Fe(II), Fe(II)-NO and Fe(II)-CO].…”

“…Furthermore, the inhibition of Pa HahK activity by NO bound Pa H-NOX was shown to be dose-dependent. 29 Additionally, a cognate response regulator (homologous to the HD-GYP domain in the S. oneidensis H-NOX/HaHK pathway) was identified via a bioinformatics screen. By homology, the P. atlantica H-NOX signaling pathway also contains the EAL and HTH-domain containing response regulators, 55 but only the HD-GYP protein has been biochemically characterized in this system.…”

“…33 The most common arrangement is for hnoX to be in the same putative operon as an orphan two-component signaling histidine kinase (without a cognate response regulator in the same operon). 29 The histidine kinase and diguanylate cyclase proteins found adjacent to H-NOX domains typically do not contain a sensory domain. Consequently, it is hypothesized that H-NOX functions as a NO sensor and regulates the downstream signaling activities of these proteins in trans .…”