Kinetic and Surface Properties of alpha-synuclein : Investigating the Difference between Pure Peptide and Phospholipid Including Aggregates

Abstract: Popular summary Parkinson's Disease is a disorder caused by brain that affects patients' coordination, movement as well as causing tremor. The onset of Parkinson's Disease is found to be the large fibrillar aggregates in the brain which consists mostly alpha-synuclein protein. The disease propagation has also been associated with membrane disruption. It is important to investigate the interaction of alpha-synuclein with lipid membranes since it gives an idea about how the things work in a cell. In this project, the fibrillation kinetics and surface properties of alpha-synuclein in presence or without the presence of lipids are studied in model systems using several different techniques, including fluorescence spectroscopy, quartz crystal microbalance with dissipation (QCM-D) and ellipsometry. It is found that the presence of anionic lipids makes fibrillation process faster than when protein without any additives in solution. Lipid to protein ratio is found out to be inversely proportional to the time waited before fibrillation starts. Lastly, both the binding of fluorescent probes and the surface technique studies suggest that the aggregates that contain only peptide have different surface properties compared to the ones that contain lipids.