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Control of Aggregated Bacterial Communities through Engineered Surface Displayed Proteins


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.


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.

Item Type:Thesis (Senior thesis (Major))
Subject Keywords:Bacterial aggregation;photoswitch;computational protein design;photoactive yellow protein;autodisplay;synzip
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemical Engineering
Minor Option:Computer Science
Awards:Frederic W. Hinrichs, Jr., Memorial Award, 2019. Donald S. Clark Memorial Award, 2018.
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Tirrell, David A.
Thesis Committee:
  • None, None
Defense Date:12 June 2019
Record Number:CaltechTHESIS:06102019-011804885
Persistent URL:
Johnstone, Christopher Patrick0000-0002-7255-0218
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11731
Deposited By: Christopher Johnstone
Deposited On:13 Jun 2019 21:15
Last Modified:08 Nov 2023 00:37

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