%0 Thesis
%A van Maarschalkerweerd, Andreas
%T Structural and biophysical characterization of α-synuclein and itsinteraction with lipid membranes
%I University of Copenhagen
%V Dr.
%M PUBDB-2015-00716
%P -
%D 2014
%Z Post referee full text in progress.
%Z University of Copenhagen, Diss., 2014
%X Parkinson's disease (PD) is a pervasive neurodegenerative disorder affecting millions of lives worldwide. There is currently no cure for PD and the pharmacological treatment is hence only symptomatic. Despite immense scientific efforts, there is still a lack of basic understanding of the pathogenesis of PD. Such understanding might be the key to optimized drug discovery strategies. Due to the outspoken similarities between PD and a number of other neurodegenerative and amyloid diseases, an enhanced understanding of PD is potentially also of general interest.PD is hallmarked by the presence of lipid-rich protein inclusions in the brain called Lewy Bodies (LB). LB are characterized by a high content of the α-synuclein (αSN) protein. A number of familiar point mutations within αSN have been shown to cause early-onset genetic PD. The native structure of αSN is generally believed to be intrinsically disordered. However, within LB αSN is found as elongated aggregates (amyloid fibrils) characterized by cross-β structure. The fibrillated αSN found in LB is believed to be an inert reservoir. The cytotoxic effect of αSN is allegedly associated with the occurrence of transient oligomer structures that form prior to the formation of amyloid fibrils. Several studies have sought to elucidate on the molecular mechanism of αSN interaction with lipid membranes in relation to the apparent cytotoxicity of oligomeric αSN.This thesis presents experimental work addressing the structure of αSN, aspects of αSN-membrane interaction and process behind αSN mutant fibrillation. The primary experimental methods are small-angle X-ray scattering (SAXS) and fluorescence spectroscopy with emphasis on the environmental sensitive dye Laurdan.During purification of αSN we observed an unexpected chromatographic feature. This feature was revealed to be a consequence of the formation of partly compacted covalent αSN dimers as shown by e.g. SAXS and mass spectroscopy. Two projects were performed on the interactions of αSN and lipid membranes. Here we showed that αSN is able to dehydrate anionic membranes and to induce lysis of liposomes associated with the formation of α-helical rich αSN-lipid co-aggregates. Additionally we showed that cholesterol could modulate the interaction between αSN oligomers and otherwise inert neutral lipid membranes. Finally a SAXS based study was conducted on the fibrillation of αSN E46K mutant proving that the fibrillation of E46K is significantly different from that of wild-type αSN under the applied conditions.
%K Dissertation (GND)
%F PUB:(DE-HGF)11
%9 Dissertation / PhD Thesis
%U https://bib-pubdb1.desy.de/record/206202