Investigating the Biochemical Properties and Functional Oligomerization of the Human i-AAA Protease YME1L

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Chen, Ching
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University of Guelph

Human i-AAA YME1L, is an ATP-dependent protease tethered to the mitochondrial inner membrane. Its functions include removing oxidized and misfolded proteins to maintain mitochondria proteostasis. To date, in vitro experiments and progress in electron cryomicroscopy (cryo-EM) have led to better understanding of the mechanisms by which YME1L processes and translocates substrates. YME1L is active as a hexamer, however, its oligomerization behavior under various nucleotide states remains to be fully understood. In this thesis, YME1L and its mutants were expressed as soluble protein constructs, followed by characterization using biochemical assays. Next, the oligomerization and thermostability of YME1L were investigated with size exclusion chromatography and dynamic light scattering. Additionally, solution nuclear magnetic resonance (NMR) spectroscopy experiments were performed to study the AAA+ domain of YME1L. The findings from this thesis provide novel insights into the oligomerization and enzymatic properties of YME1L which pave the way for further biochemical and biophysical studies.

Mitochondrial proteostasis, AAA+ enzymes, Membrane proteins, solution NMR, Methyl TROSY, Dynamic light scattering