Hughes, MDG orcid.org/0000-0001-5838-7939, Hanson, BS orcid.org/0000-0002-6079-4506, Cussons, S et al. (3 more authors) (2021) Control of Nanoscale In Situ Protein Unfolding Defines Network Architecture and Mechanics of Protein Hydrogels. ACS Nano, 15 (7). acsnano.1c00353. pp. 11296-11308. ISSN 1936-0851
Abstract
Hierarchical assemblies of proteins exhibit a wide-range of material properties that are exploited both in nature and by artificially by humankind. However, little is understood about the importance of protein unfolding on the network assembly, severely limiting opportunities to utilize this nanoscale transition in the development of biomimetic and bioinspired materials. Here we control the force lability of a single protein building block, bovine serum albumin (BSA), and demonstrate that protein unfolding plays a critical role in defining the architecture and mechanics of a photochemically cross-linked native protein network. The internal nanoscale structure of BSA contains “molecular reinforcement” in the form of 17 covalent disulphide “nanostaples”, preventing force-induced unfolding. Upon addition of reducing agents, these nanostaples are broken rendering the protein force labile. Employing a combination of circular dichroism (CD) spectroscopy, small-angle scattering (SAS), rheology, and modeling, we show that stapled protein forms reasonably homogeneous networks of cross-linked fractal-like clusters connected by an intercluster region of folded protein. Conversely, in situ protein unfolding results in more heterogeneous networks of denser fractal-like clusters connected by an intercluster region populated by unfolded protein. In addition, gelation-induced protein unfolding and cross-linking in the intercluster region changes the hydrogel mechanics, as measured by a 3-fold enhancement of the storage modulus, an increase in both the loss ratio and energy dissipation, and markedly different relaxation behavior. By controlling the protein’s ability to unfold through nanoscale (un)stapling, we demonstrate the importance of in situ unfolding in defining both network architecture and mechanics, providing insight into fundamental hierarchical mechanics and a route to tune biomaterials for future applications.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 The Authors. Published by American Chemical Society. This is an open access article under the terms of the Creative Commons Attribution License (CC-BY) |
Keywords: | protein hydrogels; protein unfolding; hierarchical biomechanics; biomaterials; biomimetic and bioinspired materials |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Molecular & Nanoscale Physics |
Funding Information: | Funder Grant number EPSRC (Engineering and Physical Sciences Research Council) EP/P02288X/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 29 Jul 2021 13:17 |
Last Modified: | 09 Jan 2025 08:59 |
Status: | Published |
Publisher: | American Chemical Society (ACS) |
Identification Number: | 10.1021/acsnano.1c00353 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:176526 |