title: Reversible mechanical unzipping of amyloid beta-fibrils.
abstract: Amyloid fibrils are self-associating filamentous structures, the deposition of which is considered to be one of the most important factors in the pathogenesis of Alzheimer's disease and various other disorders. Here we used single molecule manipulation methods to explore the mechanics and structural dynamics of amyloid fibrils. In mechanically manipulated amyloid fibrils, formed from either amyloid beta (Abeta) peptides 1-40 or 25-35, beta-sheets behave as elastic structures that can be "unzipped" from the fibril with constant forces. The unzipping forces were different for Abeta1-40 and Abeta25-35. Unzipping was fully reversible across a wide range of stretch rates provided that coupling, via the beta-sheet, between bound and dissociated states was maintained. The rapid, cooperative zipping together of beta-sheets could be an important mechanism behind the self-assembly of amyloid fibrils. The repetitive force patterns contribute to a mechanical fingerprint that could be utilized in the characterization of different amyloid fibrils.
authors.affiliation: Department of Biophysics, University of Pécs, Faculty of Medicine, Pécs H-7624, Hungary. miklos.kellermayer.jr@aok.pte.hu
authors.forename: Miklós S Z
authors.initials: MS
authors.lastname: Kellermayer
authors.forename: László
authors.initials: L
authors.lastname: Grama
authors.forename: Arpád
authors.initials: A
authors.lastname: Karsai
authors.forename: Attila
authors.initials: A
authors.lastname: Nagy
authors.forename: Amram
authors.initials: A
authors.lastname: Kahn
authors.forename: Zsolt L
authors.initials: ZL
authors.lastname: Datki
authors.forename: Botond
authors.initials: B
authors.lastname: Penke
mesh_terms: D000327:Adsorption; D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000502:physiology*; D006801:Humans; D018625:Microscopy, Atomic Force; D008962:Models, Theoretical; D010446:Peptide Fragments / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D017433:Protein Structure, Secondary; D013053:Spectrophotometry; D013997:Time Factors
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D010455:Peptides; C078592:amyloid beta-protein (1-40); C074636:amyloid beta-protein (25-35)