Control of Aggregated Bacterial Communities through Engineered Surface Displayed Proteins

Citation

Johnstone, Christopher Patrick (2019) Control of Aggregated Bacterial Communities through Engineered Surface Displayed Proteins. Senior thesis (Major), California Institute of Technology. doi:10.7907/827E-J857. https://resolver.caltech.edu/CaltechTHESIS:06102019-011804885

Abstract

Bacterial aggregation through surface display of cross-associating proteins has previously been demonstrated, but the formation of these aggregates is only controllable and reversible through the addition of chemical inducers or soluble proteins. Here, we present a design for a photoswitchable surface-display system that causes bacterial aggregation. This system should reversibly disaggregate under exposure to blue light. We created our mutant by modifying Photoactive Yellow Protein (PYP), a fluorescent protein that undergoes a large reversible conformational change when exposed to blue light. We computationally designed this mutant to drive photoswitchable sequestration of a cap domain that is designed to selectively aggregate with SynZip18. Characterization of this designed protein's photoactivity was inconclusive due to its limited solubility though the synthesized chormophore, a p-coumaric acid derivative, was capable of reconstituting native photoactive PYP. While we did not show that the designed mutant could cause disaggregation under exposure to blue light, it was capable of selectively aggregating with surface displayed SynZip18 as desired.

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