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Twisted Ribbon Aggregates in a Model Peptide System.
- Source :
-
Langmuir : the ACS journal of surfaces and colloids [Langmuir] 2019 Apr 30; Vol. 35 (17), pp. 5802-5808. Date of Electronic Publication: 2019 Apr 18. - Publication Year :
- 2019
-
Abstract
- The model peptides A <subscript>8</subscript> K and A <subscript>10</subscript> 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.
Details
- Language :
- English
- ISSN :
- 1520-5827
- Volume :
- 35
- Issue :
- 17
- Database :
- MEDLINE
- Journal :
- Langmuir : the ACS journal of surfaces and colloids
- Publication Type :
- Academic Journal
- Accession number :
- 30955339
- Full Text :
- https://doi.org/10.1021/acs.langmuir.8b03886