Investigating a Parkinson’s Associated Protein Alpha-Synuclein: A Study of Fibril Restructuring via Lipid Binding

Abstract

Alpha-synuclein (α-syn) is a small presynaptic protein that is believed to play an important role in the pathogenesis of Parkinson's disease (PD). α-syn has been shown to cluster to presynaptic mitochondria in response to cardiolipin (CL) exposure from the inner to outer mitochondrial membrane, facilitating the restructuring of α-syn fibrils toward their non-toxic membrane-bound monomer form. We utilize solid-state Nuclear Magnetic Resonance (ssNMR) to site-specifically characterize this lipid-mediated restructuring of the fibril form. We begin with chemical shift assignments of the mobile C-terminal tail for the monomeric membrane-bound form with extension to the fibril form, then report partial assignments of the rigid fibril core. Results suggest that lipid induced restructuring is not CL specific, with similar changes to the fibril form via another anionic lipid, DOPA. Only partial transition to α-helical structure is observed while much of the original β-sheet fibril structure persists, suggesting only partial N-terminal binding.