Disintegration of Amyloid fibrils using chaperones, inorganic chemicals

Abstract

Protein aggregation in the form of amyloid has been implicated in more than 50 human diseases. These diseases range from neuropathic, like Alzheimer’s and Parkinson’s, to common diseases like cataracts. The number of people getting affected by amyloid is increasing. It is estimated that by 2050, Parkinson’s will impact more than 12 million individuals, Alzheimer’s will impact more than 13 million, and 50 million affected with cataracts. This significant impact inspired us to explore how amyloid fibrils could be disintegrated and what methods could be employed. We decided to use two heavily studied model proteins for amyloid aggregation, namely ‘Insulin’ and ‘BSA.’ A wide range of biophysical and biochemical techniques like ThT fluorescence, Bradford's protein assay, light scattering, SDS-Page, FTIR, and limited protease digestion were utilized to distinguish, identify, and characterize the most significant differences caused by inorganic reagents on the amyloid fibrils. In these studies, we were able to find out that inorganic chemicals such as NaOH and KOH could dissolve amyloid fibrils. The fibrils got broken down into structures comparable to monomeric forms of the protein. The monomers produced from fibrils were structurally different from native protein monomers, as supported by the spectroscopic and biochemical data discussed here. It appears more likely that the effect induced by these inorganic solvents is primarily due to a change in the pH to highly basic that endows new charges to the amino acid side-chain groups. We also wanted to investigate amyloid disintegrating molecules closer to the physiological pH, which could be tolerated by the living cells and directed our efforts towards the chaperone system (Hsp70/Hsp40) on amyloid disassembly. Due to time constraints, we could only express the proteins, confirm their purity, and determine that they were enzymatically active. The future directions for this project would be to focus on achieving amyloid fibril disassembly by methods closer to physiological environment.