PNNL

Abstract

Cyanobacteria can utilize sunlight to capture CO2 and convert it into sugars. By pairing the sucrose synthesizing Synechococcus elongatus PCC7942 with a yeast cell bio-factory, there is potential for generation of carbon-neutral bioproducts, evading the traditional demand for obtaining sugars from grains and competing with food production. Traditional methods for bioproduction revolves around burning fossil fuels for the essential nitrogen fixation in yeast metabolic processes, a method that pollutes the atmosphere with excess CO2. A solution this project looks towards is microbial communities. However, assembly of effective engineered microbial community requires exhaustive understanding of the cyanobacteria metabolism including revealing intrinsic insights on activation or suppression of function of transcriptional regulators, which control metabolism by expression of most genes. This project was focused on comparative investigation of transcriptional regulators in three model cyanobacteria including S. elongatus PCC 7942, Synechococcus sp. PCC 7002, and Synechocystis sp. PCC 6803. Specifically, we examined the importance of cysteine oxidative post-translational modifications to function as redox-switches that modulate activity of transcriptional factors by inducing protein structural changes in response to oxidative stimuli. Results demonstrated several redox sensitive regulators consistent within all three organisms, though more than half of the genes in the proteomic analysis showed to be specific to its microbe. Furthermore, the overlapping transcriptional regulators mentioned earlier were recorded for our datasets, as these regulators were proving to be essential for the engineering of the intended microbial community. Additional methods in comparisons are being looked towards for a more thorough analysis with these regulators, and different methods for perturbation tests are being examined by members of the team. Better comprehension of the mechanisms governing activity of these essential regulatory factors can be used to engineer novel and more efficient biomanufacturing platforms that do not pollute the atmosphere, but rather utilize atmospheric CO2 as a resource.