Formation of Covalent Linked Oligomers of alpha‐Synuclein using Photoinduced Generation of Tyrosyl Radicals

BORSARELLI CD; OSTATNÁ V; FAUERBACH JA; FALOMIR LOCKHART LJ; PALECEK E; JARES ERIJMAN EA; JOVIN TM

Salta

Congreso; 3rd Latin American Protein Society Meeting; 2010

LatinAmerican Protein Society

Alpha‐synuclein (AS), a 140 aminoacid presynaptic protein, is the mayor component of the fibrillar aggregates observed in dopaminergic neurons of Parkinson’s disease patients. It is believed that oligomeric (dimer, trimer, ..., n-mer) AS arise asintermediates in the aggregation of aS and may constitute the major neurotoxic species. However, attempts to isolate such non‐covalent oligomers have not been very successful, presumably due to their transient nature, low concentration, and inherent instability. In this work, we prepared covalent oligomeric species of AS by action of protein tyrosyl radicals generated by blue‐light photosensitization of the metal coordination complex ruthenium (II) tris‐bipyridine (Rubpy) in the presence of ammonium persulfate (APS). The reaction is tyrosil radical mediated crosslinking. Photosensitized crosslinking of AS allows the formation of a progressive and controlled formation of stable covalent oligomeric species in a fast a simple fashion. The citotoxic effect of the individual species is currently under study .