Stabilization of Insulin by Adsorption on a Hydrophobic Silane Self-Assembled Monolayer



Mauri, Sergio, Volk, Martin ORCID: 0000-0003-3555-8584, Byard, Stephen, Berchtold, Harald and Arnolds, Heike ORCID: 0000-0002-5723-9309
(2015) Stabilization of Insulin by Adsorption on a Hydrophobic Silane Self-Assembled Monolayer. Langmuir, 31 (32). pp. 8892-8900.

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Abstract

The interaction between many proteins and hydrophobic functionalized surfaces is known to induce β-sheet and amyloid fibril formation. In particular, insulin has served as a model peptide to understand such fibrillation, but the early stages of insulin misfolding and the influence of the surface have not been followed in detail under the acidic conditions relevant to the synthesis and purification of insulin. Here we compare the adsorption of human insulin on a hydrophobic (−CH3-terminated) silane self-assembled monolayer to a hydrophilic (−NH3+-terminated) layer. We monitor the secondary structure of insulin with Fourier transform infrared attenuated total reflection and side-chain orientation with sum frequency spectroscopy. Adsorbed insulin retains a close-to-native secondary structure on both hydrophobic and hydrophilic surfaces for extended periods at room temperature and converts to a β-sheet-rich structure only at elevated temperature. We propose that the known acid stabilization of human insulin and the protection of the aggregation-prone hydrophobic domains on the insulin monomer by adsorption on the hydrophobic surface work together to inhibit fibril formation at room temperature.

Item Type: Article
Uncontrolled Keywords: Silanes, Insulin, Proteins, Temperature, Adsorption, Surface Properties, Models, Molecular, Hydrophobic and Hydrophilic Interactions
Subjects: ?? QD ??
Depositing User: Symplectic Admin
Date Deposited: 08 Oct 2015 14:36
Last Modified: 16 Dec 2022 16:00
DOI: 10.1021/acs.langmuir.5b01477
Publisher's Statement : © 2015 American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited (see http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html ).
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URI: https://livrepository.liverpool.ac.uk/id/eprint/2030239