Jiang Wu
Graduate student

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Rhodobacter capsulatus, a purple nonsulfur photosynthetic bacterium is among the most metablically diverse organisms known. Being able to grow via photosynthesis, respiration, fementation, as well as fix nitrogen, synthesize tetrapyrroles, chlorophylls, heme, and vitamin B12, Rhodobacter capsulatus has become one model organism for the study of phtosynthesis and general physiology of purple photosynthetic bacteria.

Many physiological processes in purple photosynthetic bacteria are highly regulated by environmental oxygen tension (redox). Studies from our lab have shown that RegB/RegA, a global two-component signal transduction system, is responsible for the redox regulation of many energy generating and energy utilizing metabolic processes including photosynthesis, electron transfer, respiration, carbon fixation, nitrogen fixation et al. RegB, the sensor kinase of RegB/RegA system, undergoes autophosphorylation in response to low oxygen tensions. The phosphrylated RegB is capable of transphosphrylating its cognate response regulator, RegA. Once phosphorylated, RegA can bind DNA and act as repressor or activator of genes involved in many metabolic processes.

My research interest is to unravel the redox-sensing mechanism of RegB. Recent work has identified ubiquinone as the direct redox signal for RegB, as well as a ubiquinone-binding site located in the periplasmic loop between transmembrane helices 3 and 4. I will focus on investigating how the ubiquinone signal interacts with some critical residues and modulate the kinase activity of RegB using genetic, biochemical and biophysical methods.