Project description:Extremely slow growth imposed by energy limitation is a ubiquitous but poorly understood physiological state for microbes. We used oxygen limitation to impose this state on Pseudomonas aeruginosa and measured newly synthesized proteins using a time-selective proteome labeling method (BONCAT) to identify relevant regulators and metabolic pathways. We further characterized one upregulated protein that has no homology to any known protein domains. This small, acidic protein is post-transcriptionally regulated and physically interacts with RNA polymerase, binding near the secondary channel during transcription elongation, and leading to widespread effects on gene expression. For some genes, the impacts on transcript and protein levels are different, suggesting possible modulation of translation as well. These effects have phenotypic consequences, as deletion of the gene affects biofilm formation, secondary metabolite production, and fitness in fluctuating conditions. Based on these phenotypes, we have designated the protein SutA (survival under transitions).
