Single-molecule analysis of osmolyte-mediated nanomechanical unfolding behavior of a protein domain.

The small organic molecules, known as osmolytes being ubiquitously present in different cell types, affect protein folding, stability and aggregation. However, it is unknown how the osmolytes affect the nanomechanical unfolding behavior of protein domain. Here, we show the osmolyte-dependent mechanical unfolding properties of protein titin immunoglobulin-27 (I27) domain using an atomic force microscopy (AFM)-based single-molecule force spectroscopy.

Sequence-dependent aggregation-prone conformations of islet amyloid polypeptide.

Amyloid proteins, which aggregate to form highly ordered structures, play a crucial role in various disease pathologies. Despite many previous studies on amyloid fibrils, which are an end product of protein aggregation, the structural characteristics of amyloid proteins in the early stage of aggregation and their related aggregation mechanism still remain elusive. The role of the amino acid sequence in the aggregation-prone structures of amyloid proteins at such a stage is not understood.

Ligand-binding alters the mechanical stability of muscle protein titin domains.

Communicated by Ramaswamy H. Sarma.

Nature-Inspired Construction of Two-Dimensionally Self-Assembled Peptide on Pristine Graphene.

Peptide assemblies have received significant attention because of their important role in biology and applications in bionanotechnology. Despite recent efforts to elucidate the principles of peptide self-assembly for developing novel functional devices, peptide self-assembly on two-dimensional nanomaterials has remained challenging. Here, we report nature-inspired two-dimensional peptide self-assembly on pristine graphene via optimization of peptide-peptide and peptide-graphene interactions.

Mechanical Deformation Mechanisms and Properties of Prion Fibrils Probed by Atomistic Simulations.

Prion fibrils, which are a hallmark for neurodegenerative diseases, have recently been found to exhibit the structural diversity that governs disease pathology. Despite our recent finding concerning the role of the disease-specific structure of prion fibrils in determining their elastic properties, the mechanical deformation mechanisms and fracture properties of prion fibrils depending on their structures have not been fully characterized. In this work, we have studied the tensile deformation mechanisms of prion and non-prion amyloid fibrils by using steered molecular dynamics simulations.

Mechanical deformation mechanisms and properties of amyloid fibrils.

Amyloid fibrils have recently received attention due to their remarkable mechanical properties, which are highly correlated with their biological functions. We have studied the mechanical deformation mechanisms and properties of amyloid fibrils as a function of their length scales by using atomistic simulations. It is shown that the length of amyloid fibrils plays a role in their deformation and fracture mechanisms in such a way that the competition between shear and bending deformations is highly dependent on the fibril length, and that as the fibril length increases, so does the bending strength of the fibril while its shear strength decreases.