In facultative anaerobic bacteria, the heme nitric oxide/oxygen binding proteins (H-NOX) sense nitric oxide (NO) and regulate various communal behaviors including biofilm formation, motility, virulence, and quorum sensing. Rupture of the proximal heme iron-histidine bond during the formation of a 5-coordinate low-spin ferrous nitrosyl (5cLS Fe(II)-NO) heme is thought to be required for H-NOX activation, allowing them to interact with downstream signaling partners such as histidine kinases (HK)1. Some H-NOX homologues also contain a conserved cysteine-ligated zinc binding site, which can respond to oxidative stress, at least in vitro2. Although classified as an obligate aerobe, Caulobacter crescentus encodes an apparent NO-sensing hnox gene adjacent to a that of a HK, hnok. Cc H-NOX protein exhibits spectroscopic characteristics similar to other H-NOX homologues, including the formation of a predominantly 5cLS Fe(II)-NO heme. Surprisingly, this form is completely non-inhibitory to HnoK autophosphorylation, in contrast to what has been observed for every other related system to date. Rather, oxidation of the zinc ligand cysteine residues activates Cc H-NOX, and X-ray absorption fine-structure (EXAFS) data reveals a change in zinc coordination upon oxidation. We also generated a hnox deletion strain and investigated its impact on growth and biofilm formation as well as the total and phosphoproteome. The results show that even in the absence of NO, Cc H-NOX facilitates progression through the C. crescentus cell cycle as well as alterations of surface layer proteins, metabolic enzymes, and intracellular pyruvate levels. Phosphoproteome analysis identified the alpha subunit of E1 pyruvate dehydrogenase (PDH) as hyperphosphorylated in the hnox deletion strain. Intriguingly, Cc PDH shares significant sequence similarity to human PDH, including the phosphorylated serine residue on the E1-α subunit shown to inhibit human PDH activity. Finally, preliminary data shows that HnoK can phosphorylate PDH E1-α directly. Taken together, this data provides a mechanism by which Cc H-NOX regulates pyruvate metabolism, and ultimately surface adherence and biofilm formation, likely in response to oxidative stress. This work illustrates the breadth of H-NOX signaling mechanisms and expands our understanding of signaling pathways in which this widespread protein participates.