An integrated network analysis identifies how ArcAB enables metabolic oscillations in the nitric oxide detoxification network of Escherichia coli. Issue 8 (24th May 2017)

• Record Type: Journal Article
• Authors: Sacco, Sarah A.; Adolfsen, Kristin J.; Brynildsen, Mark P.
• Is Part Of: Biotechnology journal. Volume 12:Issue 8(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-05-24
• Subjects: cydAB -- Hmp -- Microaerobic -- Nitric oxide dioxygenase -- Two component system; Biotechnology -- Periodicals; 660.605
• DOI: 10.1002/biot.201600570
• Languages: English
• ISSNs: 1860-6768

Abstract

Abstract: The virulences of many pathogens depend on their abilities to detoxify the immune antimicrobial nitric oxide (NO). The functions of bacterial NO detoxification machinery depend on oxygen (O2 ), with O2 inhibiting some enzymes, whereas others use it as a substrate. Previously, Escherichia coli NO detoxification was found to be highly attenuated under microaerobic conditions and metabolic oscillations were observed. The oscillations in [NO] and [O2 ] were found to result from the inhibitory action of NO on aerobic respiration, the catalytic inactivation of NO by Hmp (an NO dioxygenase), and an imbalanced competition for O2 between Hmp and cytochrome terminal oxidase activity. Here the authors investigated the role of the ArcAB two component system (TCS) in microaerobic NO detoxification. The authors observed that wild‐type, Δ arcA, and Δ arcB had comparable initial NO clearance times; however, the mutant cultures failed to exhibit [NO] and [O2 ] oscillations. Using an approach that employed experimentation and computational modeling, the authors found that the loss of oscillations in Δ arcA was due to insufficient induction of cytochrome bd ‐I expression. Collectively, these results establish ArcAB as a TCS that influences NO detoxification in E. coli within the physiologically‐relevant microaerobic regime. Abstract : The virulences of many pathogens depend on their abilities to detoxify nitric oxide (NO). In low O2 environments, Escherichia coli NO detoxification is highly attenuated and metabolic oscillations have been observed. We investigated the role of the ArcAB two component system in microaerobic NO detoxification and found it to be essential for NO and O2 oscillations through its induction of CydAB. CyoABCD was also found to influence oscillations, but it was not required for them.