Paul was an invited speaker at the Gordon Conference on Photosynthesis, at Sunday River Resort, Maine. His talk was in the session, "Manipulation of Photosynthesis for Energy and Products." The talk was
"Chemoproteomics to Identify Metabolite Regulation of Photosynthesis and Carbon Fixation”
Metabolic engineering of microbes to produce compounds of interest often involves dramatic alteration of metabolite pools. An often-overlooked consequence is that accumulating metabolites may negatively affect enzyme activity through competitive or allosteric inhibition. Additionally, post-translational regulation of enzyme activity can complicate metabolic engineering, as pathway flux becomes less sensitive to artificial enzyme overexpression. Here I will describe our application of chemoproteomics methods to identify metabolite-protein interactions in the proteomes of cyanobacteria and chloroplasts. In a first study, we found widespread interaction of tested metabolites with enzymes in central carbon metabolism, but that only a fraction of these interactions affect catalysis. For example, the Calvin cycle intermediate glyceraldehyde phosphate (GAP) stimulated activity of the Calvin cycle enzyme F/SBPase in reducing conditions, representing a feed-forward activation of the cycle. In oxidizing conditions however, GAP inhibited the enzyme by promoting aggregation. Finally, I will describe efforts in mutagenizing enzymes to reduce sensitivity to metabolite regulation, by high-throughput screening of the effect of enzyme mutation on both cell growth and product synthesis rates.
Above: A graphical abstract for the presentation. The protein landscape subfigure is from Wittman et al 2019
*Rui winning fans in Singapore (blurry) *
Anna the Second taking cultures for a gas exchange
