A fundamental feature of a living system is its integrated network of biochemical pathways that respond to endogenous stresses as well as those applied by the environment. Microbes, particularly those with a well- developed genetic system, provide a unique opportunity for the characterization of stress responses that have evolved to control reactive metabolites generated by metabolic processes. Metabolic strategies are conserved across biology, and insights obtained from microbial systems provide the means to advance our understanding of general metabolic paradigms. The long-term goal of the PI's research is to understand the robustness and redundancy of the metabolic network, and to define metabolic components and the processes they participate in. A rigorous understanding of metabolic processes is critical to efforts aimed at predicting how cells respond to environmental change, to efforts aimed at treating metabolic diseases, and to efforts targeting metabolism for rational drug design and/or production of value chemicals, to name a few. The goal of the work proposed herein is to characterize a metabolic stress that results form reactive metabolites generated during growth and to understand the family of proteins that neutralize this stress. This study focuses on the highly conserved Rid protein family, and the founding bacterial member RidA. In the current proposal we will: i) further our understanding of the mechanism used by RidA and other family members to eliminate endogeneously generated enamine/imine stress; ii) describe additional, distinct mechanisms that have evolved to deal with similar stress; and iii) explore the breadth of this stress and how different organisms handle it. The goals of this proposal will be accomplished through the combination of chemical, biochemical, biophysical, molecular, genetic and bioinformatics approaches. The work here is motivated by our desire to understand the metabolic stress generated by the production of reactive metabolites during growth, and how it can damage cellular components if it is not neutralized.

Public Health Relevance

Metabolism describes the processes required for life in all biological systems. Understanding metabolism is essential for biomedical progress including targeting metabolism for rational drug design and/ or production of small molecules. Our work contributes to this understanding by defining the biochemical function and metabolic role for a family of proteins that is conserved from bacteria to man.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Prokaryotic Cell and Molecular Biology Study Section (PCMB)
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Barski, Oleg
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University of Georgia
Schools of Arts and Sciences
United States
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Borchert, Andrew J; Downs, Diana M (2017) Endogenously generated 2-aminoacrylate inhibits motility in Salmonella enterica. Sci Rep 7:12971
Borchert, Andrew J; Downs, Diana M (2017) The Response to 2-Aminoacrylate Differs in Escherichia coli and Salmonella enterica, despite Shared Metabolic Components. J Bacteriol 199:
ElRamlawy, Kareem Gamal; Fujimura, Takashi; Baba, Koji et al. (2016) Der f 34, a Novel Major House Dust Mite Allergen Belonging to a Highly Conserved Rid/YjgF/YER057c/UK114 Family of Imine Deaminases. J Biol Chem 291:21607-21615
Ernst, Dustin C; Anderson, Mary E; Downs, Diana M (2016) L-2,3-diaminopropionate generates diverse metabolic stresses in Salmonella enterica. Mol Microbiol 101:210-23
Niehaus, Thomas D; Gerdes, Svetlana; Hodge-Hanson, Kelsey et al. (2015) Genomic and experimental evidence for multiple metabolic functions in the RidA/YjgF/YER057c/UK114 (Rid) protein family. BMC Genomics 16:382
Downs, Diana M; Ernst, Dustin C (2015) From microbiology to cancer biology: the Rid protein family prevents cellular damage caused by endogenously generated reactive nitrogen species. Mol Microbiol 96:211-9
Ernst, Dustin C; Downs, Diana M (2015) 2-Aminoacrylate Stress Induces a Context-Dependent Glycine Requirement in ridA Strains of Salmonella enterica. J Bacteriol 198:536-43
Niehaus, Thomas D; Nguyen, Thuy N D; Gidda, Satinder K et al. (2014) Arabidopsis and maize RidA proteins preempt reactive enamine/imine damage to branched-chain amino acid biosynthesis in plastids. Plant Cell 26:3010-22
Ernst, Dustin C; Lambrecht, Jennifer A; Schomer, Rebecca A et al. (2014) Endogenous synthesis of 2-aminoacrylate contributes to cysteine sensitivity in Salmonella enterica. J Bacteriol 196:3335-42
Flynn, Jeffrey M; Downs, Diana M (2013) In the absence of RidA, endogenous 2-aminoacrylate inactivates alanine racemases by modifying the pyridoxal 5'-phosphate cofactor. J Bacteriol 195:3603-9

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