Distinct thermodynamic signatures of oligomer generation in the aggregation of the amyloid-β peptide

Research output: Contribution to journalArticle

Abstract

Mapping free-energy landscapes has proved to be a powerful tool for studying reaction mechanisms. Many complex biomolecular assembly processes, however, have remained challenging to access using this approach, including the aggregation of peptides and proteins into amyloid fibrils implicated in a range of disorders. Here, we generalize the strategy used to probe free-energy landscapes in protein folding to determine the activation energies and entropies that characterize each of the molecular steps in the aggregation of the amyloid-β peptide (Aβ42), which is associated with Alzheimer's disease. Our results reveal that interactions between monomeric Aβ42 and amyloid fibrils during fibril-dependent secondary nucleation fundamentally reverse the thermodynamic signature of this process relative to primary nucleation, even though both processes generate aggregates from soluble peptides. By mapping the energetic and entropic contributions along the reaction trajectories, we show that the catalytic efficiency of Aβ42 fibril surfaces results from the enthalpic stabilization of adsorbing peptides in conformations amenable to nucleation, resulting in a dramatic lowering of the activation energy for nucleation.

Details

Authors
  • Samuel I.A. Cohen
  • Risto Cukalevski
  • Thomas C.T. Michaels
  • A. Šarić
  • Mattias Törnquist
  • Michele Vendruscolo
  • Christopher M. Dobson
  • Alexander K. Buell
  • Tuomas P.J. Knowles
  • Sara Linse
Organisations
External organisations
  • University of Cambridge
  • Harvard University
  • University College London
  • Heinrich Heine University Düsseldorf
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biochemistry and Molecular Biology
Original languageEnglish
Pages (from-to)523-531
Number of pages9
JournalNature Chemistry
Volume10
Issue number5
Publication statusPublished - 2018 May 1
Publication categoryResearch
Peer-reviewedYes