PROTEIN STRUCTURE, STABILITY AND DYNAMICS IN CELLS AND CELL-LIKE ENVIRONMENTS Public Deposited

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  • March 19, 2019
Creator
  • Smith, Austin
    • Affiliation: College of Arts and Sciences, Department of Chemistry
Abstract
  • The intracellular milieu is filled with small molecules, nucleic acids, lipids and proteins. Theories have attempted to explain how macromolecules react to this environment for over 30 years. Recent experiment-based studies have shown that protein stability and dynamics are altered in this environment. I used the loop of chymotrypsin inhibitor 2 and two unfolded proteins (α-synuclein and FlgM) to show that the crowded cellular matrix does not necessarily cause structuring of these dynamic regions. Most importantly, I have shown the thermodynamic and mechanistic basis for how protein stability is changed in the cellular environment. To do this I use a marginally stable globular protein (an isolated SH3 domain) to measure stability, dynamics, and folding rates in cells and cell-like environments. Proteins are enthalpically destabilized in cells. The destabilization arises from charge-charge interactions of the cellular environment with the unfolded ensemble of the protein. These interactions also slow folding of the protein. This work will allow creation of a more complete picture of protein thermodynamics inside the cell. Furthermore, the SH3 domain is amenable to studying in vitro protein stability over a broad range of pH values, and allows acquisition of folding and unfolding rates with a variety of crowders. Future efforts will facilitate a better understanding of surface charge interactions and will allow elucidation of a crowder’s interaction with the transition state.
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  • In Copyright
Advisor
  • Thompson, Nancy
  • Berkowitz, Max
  • Pielak, Gary J.
  • Lee, Andrew
  • Spremulli, Linda
Degree
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2015
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Place of publication
  • Chapel Hill, NC
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