Identifying the coiled-coil triple helix structure of β-peptide nanofibers at atomic resolution

Christofferson, Andrew J, Al-Garawi, Zahraa S, Todorova, Nevena, Turner, Jack, Del Borgo, Mark Pasqualino, Serpell, Louise C, Aguilar, Marie-Isabel and Yarovsky, Irene (2018) Identifying the coiled-coil triple helix structure of β-peptide nanofibers at atomic resolution. ACS Nano, 12 (9). pp. 9101-9109. ISSN 1936-0851

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Peptide self-assembly represents a powerful bottom-up approach to the fabrication of new nanomaterials. β3-peptides are non-natural peptides composed entirely of β-amino acids, which have an extra methylene in the backbone and we reported the first fibers derived from the self-assembly of β3-peptides that adopt unique 14-helical structures. β3-peptide assemblies represent a class of stable nanomaterials that can be used to generate bio- and magneto-responsive materials with proteolytic stability. However, the three-dimensional structure of many of these materials remains unknown. In order to develop structure-based criteria for the design of new β3-peptide-based biomaterials with tailored function, we investigated the structure of a tri-β3-peptide nanoassembly by molecular dynamics simulations and X-ray fiber diffraction analysis. Diffraction data was collected from aligned fibrils formed by Ac-β3[LIA] in water and used to inform and validate the model structure. Models with threefold radial symmetry resulted in stable fibers with a triple-helical coiled-coil motif and measurable helical pitch and periodicity. The fiber models revealed a hydrophobic core and twist along the fiber axis arising from a maximization of contacts between hydrophobic groups of adjacent tripeptides on the solvent-exposed fiber surface. These atomic structures of macro-scale fibers derived from β3-peptide-based materials provide valuable insight into the effects of the geometric placement of the side-chains and the influence of solvent on the core fiber structure which is perpetuated in the superstructure morphology.

Item Type: Article
Schools and Departments: School of Life Sciences > Biochemistry
Research Centres and Groups: Dementia Research Group
Subjects: Q Science
Q Science > QD Chemistry
Depositing User: Louise Serpell
Date Deposited: 31 Aug 2018 08:35
Last Modified: 17 Oct 2018 16:25

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