Investigation of the Cu(II)-Binding Properties of Alpha-Synuclein

Abstract

Parkinson's disease is a chronic, progressive, and often fatal neurodegenerative disorder that affects 1 in 100 individuals over the age of 60. The hallmark of Parkinson's disease is modified dopaminergic neurons termed Lewy Bodies, of which the protein Alpha synuclein is the primary fibular component. Epidemiological studies correlated long-term metal exposure (such as in an industrial setting) with an increased incidence of fatal Parkinson's disease. Fibril assays indicated that certain metals, notably Cu(II), Fe(III) and Al(III) increase the rate of in vitro alpha synuclein fibril formation. Our work seeks to elucidate the stoichiometry, affinities, chelating residues and binding motifs of Cu(II) to alpha synuclein. Using EPR spectroscopy to analyze recombinant alpha synuclein, mutants and synthetic peptides we have determined a heretofore unknown Cu(II) binding motif. This motif may provide insight into a possible explanation for the increase in the rate of alpha synuclein fibril formation.