Nanomechanical Deformation Behavior of Amyloid Fibrils

Abstract

Amyloid fibrils playing a role in disease expression have recently been found to exhibit excellent mechanical properties, which are highly correlated with the biological functions of amyloid fibrils. It has not yet fully understood how amyloid fibrils formed by aggregation of mechanically weak protein chains can exhibit remarkable mechanical properties. In this work, we study the nanomechanical deformation behavior of amyloid fibrils using steered molecular dynamics simulations. It is shown that the length scale of amyloid fibrils is a key factor in determining the nanomechanical deformation mechanisms of amyloid fibrils and their resulting nanomechanical properties. It is attributed to the competition between shear and bending deformations, which depends on the length scale of amyloid fibrils. The length-dependent elastic property of amyloid fibrils has been elucidated based on Timoshenko beam model. Our study sheds light on the importance of the length scale of amyloid fibrils for understanding their nanomechanical properties.