The transmissible agent of prion disease consists of prion protein (PrP) in β-sheet-rich state (PrP(Sc)) that can replicate its conformation according to a template-assisted mechanism. This mechanism postulates that the folding pattern of a newly recruited polypeptide accurately reproduces that of the PrP(Sc) template. Here, three conformationally distinct amyloid states were prepared in vitro ...

The beta-amyloid peptide (A beta), the major component of the senile plaques found in the brains of Alzheimer's disease patients, is derived from proteolytic processing of a transmembrane glycoprotein known as the amyloid precursor protein (APP). Human APP exists in various isoforms, of which the major ones contain 695, 751, and 770 amino acids. Proteolytic cleavage of APP by alpha- or beta-sec...

The 40–42 residue amyloid -protein (A ) plays a central role in the pathogenesis of Alzheimer’s disease (AD). Of the two main alloforms, A 40 and A 42, the longer A 42 is linked particularly strongly to AD. Despite the relatively small two amino acid length difference in primary structure, in vitro studies demonstrate that A 40 and A 42 oligomerize through distinct pathways. Recently, a discret...

Pathological folding and aggregation of the amyloid -protein (A ) are widely perceived as central to understanding Alzheimer’s disease (AD) at the molecular level. Experimental approaches to study A self-assembly are limited, because most relevant aggregates are quasi-stable and inhomogeneous. In contrast, simulations can provide significant insights into the problem, including specific sites i...

Experimental findings suggest that oligomeric forms of the amyloid protein (A ) play a critical role in Alzheimer’s disease. Thus, elucidating their structure and the mechanisms of their formation is critical for developing therapeutic agents. We use discrete molecular dynamics simulations and a four-bead protein model to study oligomerization of two predominant alloforms, A 40 and A 42, at the...

This review is intended to reflect the recent progress in single-molecule studies of individual peptides and peptide assemblies on surfaces. The structures and the mechanism of peptide assembly are discussed in detail. The contents include the following topics: structural analysis of single peptide molecules, adsorption and assembly of peptides on surfaces, folding structures of the amyloid pep...

amyloidoma or amyloid tumor is a tumor-like localized deposit of amyloid encountered occasionally in association with multiple myeloma, various chronic inflammatory diseases and primary amyloidosis. amyloid tumors unassociated with plasmacytoma or other disease are extremely rare in soft tissues and few cases in various situations have been reported. histologic examination discloses amorphous e...