(709f) Quantitative Dissection of Bacterial Nitric Oxide Stress Networks

Nitric oxide (NO) is an important antimicrobial produced by the immune system to neutralize pathogens. Many pathogens, such as Mycobacterium tuberculosis, Neisseria meningitides, Pseudomonas aeruginosa, and pathogenic Escherichia coli, harbor NO detoxification and repair systems that have been linked to their virulence, and thus represent attractive targets toward which novel anti-infective therapies could be identified. Unfortunately, the few compounds that have been found to inhibit bacterial NO detoxification systems suffer from poor transport or toxicity, which warrants searches for other compounds or strategies to impair those processes. To complicate matters, the broad reactivity of NO and its reaction products give rise to an expansive and interconnected biochemical reaction network whose experimental measurables are difficult to interpret. To facilitate quantitative analyses of bacterial NO stress networks, we constructed and experimentally validated a kinetic model of the E. coli NO biochemical network, including relevant processes such as enzymatic NO detoxification, iron-sulfur cluster damage and repair, DNA deamination and repair, transcriptional regulation, and NO autoxidation. Here, I will discuss how we have used this computational tool in an iterative workflow with experimentation to mechanistically investigate how a variety of chemical, genetic, and environmental perturbations alter the E. coli NO stress response, as well as how this tool could facilitate the development of next-generation antibiotics that inhibit bacterial NO defenses.