Epigallocatechin 3-Gallate as an Inhibitor of Tau Phosphorylation and Aggregation: A Molecular and Structural Insight.

Polyphenols such as Epigallocatechin-3 gallate (EGCG) are currently bearer of hope to prevent or at least to slow down the deleterious effect of Tauopathies such as Alzheimer disease. One of the main effects of these neurodegenerative pathologies is the hyperphosphorylation and consequent aggregation of the Tau protein that leads to the irremediable neuronal cells death. In the present paper, we show how EGCG can play a crucial role to prevent Tau aggregation: (i) in binding Tau in its phosphorylation region with an affinity of the same order of magnitude than kinases (0.5 mM), hindering their access to the protein and (ii) in modifying the 3D-structure of Tau whose preferential conformation changes in the presence of EGCG. For this purpose, two peptides were synthesized, one of 20 residues long issued from the first Proline-rich region of Tau (171Ile-190Lys), the second of 50 residues long (171Ile-220Thr) corresponding to more than 50% of the Tau Proline rich domaine. The total attribution of all the 1H, 13C and 15N resonances of the two peptides has been achieved thanks to a "divide and conquer" strategy leading to their 3D structure preference and their affinity towards EGCG.