Wang, Shih-Ting, Lin, Yiyang, Todorova, Nevena, Xu, Yingqi, Mazo, Manuel, Rana, Subinoy, Leonardo, Vincent, Amdursky, Nadav, Spicer, Christopher D., Alexander, Bruce D., Edwards, Alison A., Matthews, Steve J., Yarovsky, Irene and Stevens, Molly M. (2017) Facet-dependent interactions of islet amyloid polypeptide with gold nanoparticles: Implications for fibril formation and peptide-induced lipid membrane disruption. Chemistry of Materials, 29 (4). pp. 1550-1560. ISSN 0897-4756 (Print), 1520-5002 (Online) (doi:https://doi.org/10.1021/acs.chemmater.6b04144)

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Abstract

A comprehensive understanding of the mechanisms of interaction between proteins or peptides and nanomaterials is crucial for the development of nanomaterial-based diagnostics and therapeutics. In this work, we systematically explored the interactions between citrate-capped gold nanoparticles (AuNPs) and islet amyloid polypeptide (IAPP), a 37-amino acid peptide hormone co-secreted with insulin from the pancreatic islet. We utilized diffusion-ordered spectroscopy, isothermal titration calorimetry, localized surface plasmon resonance spectroscopy, gel electrophoresis, atomic force microscopy, transmission electron microscopy (TEM), and molecular dynamics (MD) simulations to systematically elucidate the underlying mechanism of the IAPP–AuNP interactions. Because of the presence of a metal-binding sequence motif in the hydrophilic peptide domain, IAPP strongly interacts with the Au surface in both the monomeric and fibrillar states. Circular dichroism showed that AuNPs triggered the IAPP conformational transition from random coil to ordered structures (α-helix and β-sheet), and TEM imaging suggested the acceleration of IAPP fibrillation in the presence of AuNPs. MD simulations revealed that the IAPP–AuNP interactions were initiated by the N-terminal domain (IAPP residues 1–19), which subsequently induced a facet-dependent conformational change in IAPP. On a Au(111) surface, IAPP was unfolded and adsorbed directly onto the Au surface, while for the Au(100) surface, it interacted predominantly with the citrate adlayer and retained some helical conformation. The observed affinity of AuNPs for IAPP was further applied to reduce the level of peptide-induced lipid membrane disruption.

Item Type:	Article
Additional Information:	ACS AuthorChoice - 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.
Uncontrolled Keywords:	Nanoparticles; Gold; Circular dichroism; Peptides
Subjects:	Q Science > QD Chemistry
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science Faculty of Engineering & Science > School of Science (SCI)
Last Modified:	19 Jun 2020 12:14
URI:	http://gala.gre.ac.uk/id/eprint/16491

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