Rational Design and Refinement of an Intracellular Derived Peptide: Deriving Potent Antagonists of Alpha-Synuclein Aggregation
: (Alternative format thesis)

Student thesis: Doctoral ThesisPhD

Abstract

Parkinson’s disease (PD) is the second most prevalent neurodegenerative disease and is characterised by Lewy body deposits in the brains of suffers, which have been shown to consist of the protein alpha synuclein (aS), and membrane lipids. Previous research utilised an intracellular peptide screen of the residues 45-54 of S, as this is where most early onset mutations reside, and selected a peptide, 4554W (KDGIVNGVKA). This peptide was shown to decrease aS aggregation, and rescue PC-12 cells from aS mediated toxicity.

Experiments were performed herein to deduce where along the aS aggregation pathway the 4554W peptide acted. It was found that the peptide inhibited primary nucleation of aS but exhibited no inhibitory effect on fibril elongation or secondary nucleation. An alanine scan was performed of 4554W to deduce the key mechanisms important for the interaction. It was found that the 4554W(K1A) and 4554W(N6A) substitutions exhibited increased. Following this truncation experiments of the C- and N-terminus were performed to determine their importance and the residue in position 1 was not required for the peptide’s function. The final peptide optimised for this thesis is termed 4654W(N6A) (DGIVAGVKA). This represents a step forward to producing a novel peptide therapeutic targeted against PD and related synucleinopathies.

In addition to the peptide optimisation, a novel aggregate of aS was observed in the presence of lipid vesicles. These structures were much larger than any previously reported aS aggregates and may represent a novel therapeutically relevant conformation.
Date of Award2 Dec 2020
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorJody Mason (Supervisor) & Robert Williams (Supervisor)

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