Asakura, T., Ogawa, T., Naito, A. et al. (1 more author) (2020) Chain-folded lamellar structure and dynamics of the crystalline fraction of Bombyx mori silk fibroin and of (Ala-Gly-Ser-Gly-Ala-Gly)n model peptides. International Journal of Biological Macromolecules, 164. pp. 3974-3983. ISSN 0141-8130
Abstract
Solid-state NMR is a powerful analytical technique to determine the composite structure of Bombyx mori silk fibroin (SF). In our previous paper, we proposed a lamellar structure for Ala-Gly copolypeptides as a model of the crystalline fraction in Silk II. In this paper, the structure and dynamics of the crystalline fraction and of a better mimic of the crystalline fraction, (Ala-Gly-Ser-Gly-Ala-Gly)n (n = 2–5, 8), and 13C selectively labeled [3-13C]Ala-(AGSGAG)5 in Silk II forms, were studied using structural and dynamical analyses of the Ala Cβ peaks in 13C cross polarization/ magic angle spinning NMR and 13C solid-state spin-lattice relaxation time (T1) measurements, respectively. Like Ala-Gly copolypeptides, these materials have lamellar structures with two kinds of Ala residues in β-sheet, A and B, plus one distorted β-turn, t, formed by repetitive folding using β-turns every eighth amino acid in an antipolar arrangement. However, because of the presence of Ser residues at every sixth residue in (AGSGAG)n, the T1 values and mobilities of B decreased significantly. We conclude that the Ser hydroxyls hydrogen bond to adjacent lamellar layers and fix them together in a similar way to Velcro®.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 Published by Elsevier B.V. This is an author produced version of a paper subsequently published in International Journal of Biological Macromolecules. Uploaded in accordance with the publisher's self-archiving policy. Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/). |
Keywords: | Bombyx mori silk fibroin; Lamellar structure; 13C CP/MAS NMR; 13C solid-state NMR relaxation time |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > School of Biosciences (Sheffield) > Department of Molecular Biology and Biotechnology (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 17 Nov 2020 12:26 |
Last Modified: | 31 Aug 2021 00:38 |
Status: | Published |
Publisher: | Elsevier BV |
Refereed: | Yes |
Identification Number: | 10.1016/j.ijbiomac.2020.08.220 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:168110 |