Twisted Ribbon Aggregates in a Model Peptide System

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The model peptides A 8 K and A 10 K self-assemble in water into ca. 100 nm long ribbon-like aggregates. These structures can be described as β-sheets laminated into a ribbon structure with a constant elliptical cross-section of 4 by 8 nm, where the longer axis corresponds to a finite number, N ≠15, of laminated sheets, and 4 nm corresponds to a stretched peptide length. The ribbon cross-section is strikingly constant and independent of the peptide concentration. High-contrast transmission electron microscopy shows that the ribbons are twisted with a pitch λ ≠15 nm. The self-assembly is analyzed within a simple model taking into account the interfacial free energy of the hydrophobic β-sheets and a free energy penalty arising from an increased stretching of hydrogen bonds within the laminated β-sheets, arising from the twist of the ribbons. The model predicts an optimal value N, in agreement with the experimental observations.


  • Axel Rüter
  • Stefan Kuczera
  • Darrin J. Pochan
  • Ulf Olsson
Enheter & grupper
Externa organisationer
  • University of Delaware
  • Lund University

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Biokemi och molekylärbiologi
Sidor (från-till)5802-5808
Antal sidor7
StatusPublished - 2019
Peer review utfördJa