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Seeking Solvation: Exploring the Role of Protein Hydration in Silk Gelation

The mechanism by which arthropods (e.g., spiders and many insects) can produce silk fibres from an aqueous protein (fibroin) solution has remained elusive, despite much scientific investigation. In this work, we used several techniques to explore the role of a hydration shell bound to the fibroin in...

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Autores principales: Laity, Peter R., Holland, Chris
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8781151/
https://www.ncbi.nlm.nih.gov/pubmed/35056868
http://dx.doi.org/10.3390/molecules27020551
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author Laity, Peter R.
Holland, Chris
author_facet Laity, Peter R.
Holland, Chris
author_sort Laity, Peter R.
collection PubMed
description The mechanism by which arthropods (e.g., spiders and many insects) can produce silk fibres from an aqueous protein (fibroin) solution has remained elusive, despite much scientific investigation. In this work, we used several techniques to explore the role of a hydration shell bound to the fibroin in native silk feedstock (NSF) from Bombyx mori silkworms. Small angle X-ray and dynamic light scattering (SAXS and DLS) revealed a coil size (radius of gyration or hydrodynamic radius) around 12 nm, providing considerable scope for hydration. Aggregation in dilute aqueous solution was observed above 65 °C, matching the gelation temperature of more concentrated solutions and suggesting that the strength of interaction with the solvent (i.e., water) was the dominant factor. Infrared (IR) spectroscopy indicated decreasing hydration as the temperature was raised, with similar changes in hydration following gelation by freezing or heating. It was found that the solubility of fibroin in water or aqueous salt solutions could be described well by a relatively simple thermodynamic model for the stability of the protein hydration shell, which suggests that the affected water is enthalpically favoured but entropically penalised, due to its reduced (vibrational or translational) dynamics. Moreover, while the majority of this investigation used fibroin from B. mori, comparisons with published work on silk proteins from other silkworms and spiders, globular proteins and peptide model systems suggest that our findings may be of much wider significance.
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spelling pubmed-87811512022-01-22 Seeking Solvation: Exploring the Role of Protein Hydration in Silk Gelation Laity, Peter R. Holland, Chris Molecules Article The mechanism by which arthropods (e.g., spiders and many insects) can produce silk fibres from an aqueous protein (fibroin) solution has remained elusive, despite much scientific investigation. In this work, we used several techniques to explore the role of a hydration shell bound to the fibroin in native silk feedstock (NSF) from Bombyx mori silkworms. Small angle X-ray and dynamic light scattering (SAXS and DLS) revealed a coil size (radius of gyration or hydrodynamic radius) around 12 nm, providing considerable scope for hydration. Aggregation in dilute aqueous solution was observed above 65 °C, matching the gelation temperature of more concentrated solutions and suggesting that the strength of interaction with the solvent (i.e., water) was the dominant factor. Infrared (IR) spectroscopy indicated decreasing hydration as the temperature was raised, with similar changes in hydration following gelation by freezing or heating. It was found that the solubility of fibroin in water or aqueous salt solutions could be described well by a relatively simple thermodynamic model for the stability of the protein hydration shell, which suggests that the affected water is enthalpically favoured but entropically penalised, due to its reduced (vibrational or translational) dynamics. Moreover, while the majority of this investigation used fibroin from B. mori, comparisons with published work on silk proteins from other silkworms and spiders, globular proteins and peptide model systems suggest that our findings may be of much wider significance. MDPI 2022-01-16 /pmc/articles/PMC8781151/ /pubmed/35056868 http://dx.doi.org/10.3390/molecules27020551 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Laity, Peter R.
Holland, Chris
Seeking Solvation: Exploring the Role of Protein Hydration in Silk Gelation
title Seeking Solvation: Exploring the Role of Protein Hydration in Silk Gelation
title_full Seeking Solvation: Exploring the Role of Protein Hydration in Silk Gelation
title_fullStr Seeking Solvation: Exploring the Role of Protein Hydration in Silk Gelation
title_full_unstemmed Seeking Solvation: Exploring the Role of Protein Hydration in Silk Gelation
title_short Seeking Solvation: Exploring the Role of Protein Hydration in Silk Gelation
title_sort seeking solvation: exploring the role of protein hydration in silk gelation
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8781151/
https://www.ncbi.nlm.nih.gov/pubmed/35056868
http://dx.doi.org/10.3390/molecules27020551
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