Targeting protein misfolding disease: synthesis, X-ray analysis and biological evaluation of new small molecules stabilizing the native quaternary structure of TTR

Transthyretin (TTR) is a 54-kDa homotetrameric protein that transports thyroxine and retinol, through its association with retinol binding protein, in plasma and cerebrospinal fluid. Under unknown conditions it aggregates to form fibrils that are responsible of TTR amyloidosis. Biophysical studies reveal that TTR tetramer dissociation is the rate limiting step for starting fibril formation process. A diffuse strategy for the prevention and treatment of TTR amyloidosis consists in stabilization of tetrameric structure of TTR to prevent amyloid fibril formation. In my phd work, a library of new ligands with a single (aryl or fluorenyl) or double aromatic portion were synthesized. The synthesized compounds were tested by the turbidimetric assay to evaluate their ability to stabilize TTR in the native tetrameric form. The most active compounds have been co-crystallized with WT-TTR and high resolution crystal structures were obtained using a new crystallization method that does not denature the WT-TTR but efficiently solubilizes the ligands. These crystal structures provide valuable information relating to the binding orientation of the compounds, the conformation and the interactions with binding site residues.