[3P-73] ATP-dependent amyloid formation of α-synuclein under ultrasonication
Although adenosine triphosphate (ATP) is one of the most important molecules in living cells, it has been reported to play a role as hydrotrope which dissolves the hydrophobic molecules in aqueous solution. However, we recently found that polyposhosphate consisting of a large number of phosphate groups significantly accelerated the amyloid formation. Here, we examined the amyloid formation of α-synuclein (αSyn) at varying concentrations of ATP under ultrasonication. We found that amyloid formation of αSyn was remarkably promoted by several millimolar concentrations of ATP, which was comparable to the concentration of ATP in the cell. The CD spectra showed that amyloid fibrils were rich in β-sheet conformation and EM observation showed that αSyn formed rigid rod-like fibrils. In addition, αSyn formed not only the amyloid fibrils but also the amorphous aggregates depending on pH of the solution. Amyloid fibrils were formed by the preferential hydration of ATP at the neutral pH, but amorphous aggregates were formed by the charge-charge interaction at the acidic conditions. Thus, ATP will have several faces; one is the property as hydrotrope and another is the property as kosmotropic salt in Hofmeister series.