Mechanism of flavonoid myricetin modulated aggregation in α-Synuclein and its familial mutants E46K and A30P.

Inhibiting the aggregation of α-Synuclein (α-Syn) and its familial mutants E46K and A30P has emerged as one of the effective therapeutic strategies against Parkinson's disease (PD). The inhibition and modulation of α-Syn/E46K/A30P fibrillation as well as disaggregation of their pre-formed fibrils by a natural flavonoid myricetin (Myr) is studied. The binding of Myr with α-Syn and its mutants with the affinity ranging 104-105 M-1. The isothermal titration calorimetry (ITC) results indicate the involvement of hydrogen binding/ionic and hydrophobic interactions in the binding process. The aggregation kinetics studies demonstrate that Myr inhibits aggregation of α-Syn/E46K/A30P in a concentration dependent manner. Seeding experiments demonstrate that the protein aggregates formed in the presence of Myr do not further instigates aggregation in healthy proteins. Myr also modulates the aggregation process of protein when added after the onset of aggregation. Circular dichroism (CD) show that Myr delays the structural transition of native α-Syn/E46K/A30P into β-sheets rich fibrillar structures. Myr also disassemble the pre-formed fibrillar structures of α-Syn its mutants. These outcomes offer profound insight into the modulatory mechanism of aggregation of α-Syn, E46K and A30P by Myr, thereby suggesting its potential role in designing combination therapies against protein fibrillation related disorders.