Date of Award

Spring 2018

Document Type


Terms of Use

© 2018 Elijah N. Kissman. All rights reserved. This work is freely available courtesy of the author. It may only be used for non-commercial, educational, and research purposes. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Chemistry & Biochemistry Department

First Advisor

Stephen T. Miller


Quorum sensing is a process by which bacteria coordinate community behaviors through the exchange of signal molecules. Both Gram-negative and Gram-positive bacteria use quorum sensing to regulate cell density-dependent activities such as bioluminescence, biofilm formation, and the secretion of virulence factors. Interspecies quorum sensing is mediated by a signal molecule known as autoinducer-2 (AI-2) which is synthesized and recognized by a diverse range of bacterial phyla. The uptake and degradation of AI -2 is accomplished by proteins encoded by the lsr operon, which is regulated by AI-2. Previous research has suggested that dihydroxyacetone phosphate (DHAP), a metabolic product of AI-2 degradation, interacts directly with LsrR to repress lsr. In this study, we report the purification protocol for LsrR from Escherichia coli and an N-terminal truncation of LsrR from Salmonella enterica ser. Typhimurium. We attempt thermodynamic and kinetic studies of DHAP binding using isothermal titration calorimetry and fluorometry. Our study also reports an initial attempt to assay the effect of DHAP on transcriptional repression by LsrR using an electrophoretic mobility shift assay. These approaches did not supply reliable data that support a conclusion regarding the role of DHAP in regulating lsr. Future studies will optimize the reported protocols and incorporate additional options to obtain conclusive results.

Included in

Chemistry Commons