Nitration inhibits fibrillation of human α‐synuclein in vitro by formation of soluble oligomers

Abstract
The aggregation of α‐synuclein in dopaminergic neurons is a critical factor in the etiology of Parkinson's disease (PD). Oxidative and nitrative stress is also implicated in PD. We examined the effect of nitration on the propensity of α‐synuclein to fibrillate in vitro. Fibril formation of α‐synuclein was completely inhibited by nitration, due to the formation of stable soluble oligomers (apparently octamers). More importantly the presence of sub‐stoichiometric concentrations of nitrated α‐synuclein led to inhibition of fibrillation of non‐modified α‐synuclein. These observations suggest that nitration of soluble α‐synuclein may be a protective factor in PD, rather than a causative one.