Title : Understanding the Aggregation Properties of Amyloid Beta Through Solid State NMR and Designed Mutations

Abstract :

Zn+2 can alter the aggregation properties and toxicity of Amyloid beta (Aβ) by selectively precipitating out the soluble oligomers. What does it change? Using Solid State NMR on fibrils Aβ40 grown in the presence of Zn+2, we show that the turn region of the peptide is affected.  We have found that the fibrils of Aβ40 grown in the presence of equal concentration of Zn+2 has a similar hairpin shape but they differs in the turn region. However what we actually need to look at are the biologically active metastable oligomers, (not the fibrils) and focus on the turn region. Using a technique recently developed in the lab for looking at metastable structures, we find that the oligomers are different only in the turn and the terminal regions. This suggests that the conformational change starts at the two hydrophobic arms of the peptide. We are now trying to selectively disturb the stereospecific interaction in the nucleation centre by selective alternation of some amino acids in to their  "dextro" forms, which leaves chemical property of the peptide unchanged.