Development of Peptide Based E3 Ligase Reporter Public Deposited

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  • March 21, 2019
  • Woss, Gregery
    • Affiliation: College of Arts and Sciences, Department of Chemistry
  • This dissertation describes the development of a new analytical tool capable of analyzing E3 ligase activity, a critical element in the ubiquitin proteasome system. This was accomplished through the development of a novel class of peptide-based fluorescent E3 ligase reporters which are intended to be analyzed by capillary electrophoresis (CE). These E3 ligase reporters incorporate a degradation signal, or degron, which is recognized and ubiquitinated by an E3 ligase, as well as a fluorescent tag to facilitate detection by laser induced fluorescence (LIF). In order to identify potent degrons, a library of E3 ligase reporters incorporating degrons from various sources was synthesized. These reporters were characterized in cell lysates, then optimized to produce substrates that would be efficiently ubiquitinated in cells. In addition to working with minimal degron sequences, an expanded sub-library of reporters based around the degron isolated from p53 was characterized in order to identify a compact degron element and investigate its ubiquitination kinetics and specificity. In order to circumvent peptidase-mediated degradation, a traditional weakness of peptide reporters, investigations were also carried out to develop novel degradation-resistant E3 ligase reporters incorporating β-hairpin secondary structures. Serendipitously, a β-hairpin that was both peptidase-resistant and functioned as an E3 ligase reporter was identified. Finally, electrophoretic separation conditions for the analysis of E3 ligase peptide reporters were identified, and ubiquitination of E3 ligase reporters in cell lysates was observed by CE-LIF. This dissertation lays the groundwork for future development of next generation peptide-based E3 ligase reporters.
Date of publication
Resource type
Rights statement
  • In Copyright
  • Wightman, R. Mark
  • Jorgenson, James
  • Allbritton, Nancy
  • Waters, Marcey
  • Lockett, Matthew
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2017

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