Hydrophobic surfaces help reduce harmful protein fibril formation

Linear arrays of proteins called amyloid fibrils are associated with many diseases, including Alzheimer’s, Parkinson’s disease and type-II diabetes. David Cheung investigated how a hydrophobic surface may affect the formation of these fibrils by studying a protein commonly found damaging the membrane of pancreatic cells in patients with type-II diabetes.

Previous research had suggested that hydrophobic surfaces can slow down fibril formation, so Cheung used replica exchange molecular dynamics simulations to study the formation of human islet amyloid polypeptide (hIAPP) on surfaces with various levels of hydrophobicity.

He found that hIAPP adopts structures on the hydrophobic surface, which are helical and less likely to conform to fibrils. Comparatively, the protein developed structures that were more accommodating to fibril formation on a hydrophilic surface.

“This explains why for this protein fibril formation was inhibited on hydrophobic surfaces despite there being a higher protein concentration on these,” said Cheung.

This research can also be applied to the study of biofilm-forming bacteria. Cheung explained that based on his research, surfaces can be designed to prevent harmful bacteria absorption.

The author hopes to expand this research by examining the attachment of protein aggregates on surfaces and to compare how different proteins react to the same surfaces.

“An interesting comparison would be between pathogenic proteins, like islet amyloid polypeptide or amyloid beta, which is involved in Alzheimer’s, and proteins that form functional fibrils,” said Cheung.

Source: “Effect of surface chemistry on islet amyloid polypeptide conformation,” by David L. Cheung, Biointerphases (2020). The article can be accessed at https://doi.org/10.1116/6.0000417 .