Study of Selective Tyrosine Oxidation and Nitration Dependence on Alpha-Synuclein Conformational Changes

ANDRÉS MARTÍN TOSCANI; BETINA CORSICO; EZEQUIEL GIMÉNEZ; GIAN FRANCO CAVAZZUTI; MARÍA ALEJANDRA CARRERO RIVEROS; LISANDRO J. FALOMIR LOCKHART

Buenos Aires

Congreso; II FALAN Congress Buenos Aires 2016; 2016

FALAN-SAN

Oxidative stress is considered one of the most relevant factors that trigger protein aggregation and toxicity during the development of Parkinson´s disease, promoting post translational modifications on proteins, lipids and nucleic acids. New data suggest that selective oxidative variants of the protein alpha-Synuclein (aSyn), the main component of the characteristic amyloid aggregates of this disease, could be participating in activation of inflammatory response, enhancing its cytotoxicity, as well as modulating its aggregation.In this project, we focus on the formation of diTyrosine covalent crosslinked and Tyrosine-nitrated residues on aSyn, evaluating the distinctive accessibility of each Tyr residue due to protein conformational changes associated with binding to membranes or aggregation. To be able to selectively oxidize aSyn, we employed a tunable photoinduced system based in the photosensitizer trisbipyridine-Ru(II) in the presence of ammonium persulfate. We also optimized a variation of this method to selectively nitrate Tyr residues. We previously evaluated the effects of wild type aSyn oxidation and formation of crosslinked oligomers comparing aSyn free form in solution with the one associated to phospholipid membranes. Now we have extended these studies to include clinical mutants and nitrated forms of aSyn, in order to produce and purify each variant for biophysical characterization and cytotoxic assays in culture model of neurons.