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Guiding the Morphology of Amyloid Assemblies by Electrostatic Capping: from Polymorphic Twisted Fibrils to Uniform Nanorods
Author(s) -
Zottig Ximena,
AlHalifa Soultan,
Babych Margaryta,
Quittot Noé,
Archambault Denis,
Bourgault Steve
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201901806
Subject(s) - nanorod , fibril , self assembly , electrostatics , peptide , static electricity , supramolecular chemistry , materials science , amyloid fibril , nanotechnology , amyloid (mycology) , sequence (biology) , mesoscopic physics , crystallography , biophysics , chemistry , amyloid β , biochemistry , crystal structure , biology , medicine , inorganic chemistry , disease , engineering , pathology , electrical engineering , physics , quantum mechanics
Peptides that self‐assemble into cross‐β‐sheet amyloid structures constitute promising building blocks to construct highly ordered proteinaceous materials and nanoparticles. Nevertheless, the intrinsic polymorphism of amyloids and the difficulty of controlling self‐assembly currently limit their usage. In this study, the effect of electrostatic interactions on the supramolecular organization of peptide assemblies is investigated to gain insights into the structural basis of the morphological diversities of amyloids. Different charged capping units are introduced at the N‐terminus of a potent β‐sheet‐forming sequence derived from the 20–29 segment of islet amyloid polypeptide, known to self‐assemble into polymorphic fibrils. By tuning the charge and the electrostatic strength, different mesoscopic morphologies are obtained, including nanorods, rope‐like fibrils, and twisted ribbons. Particularly, the addition of positive capping units leads to the formation of uniform rod‐like assemblies, with lengths that can be modulated by the charge number. It is proposed that electrostatic repulsions between N‐terminal positive charges hinder β‐sheet tape twisting, leading to a unique control over the size of these cytocompatible nanorods by protofilament growth frustration. This study reveals the high susceptibility of amyloid formation to subtle chemical modifications and opens to promising strategies to control the final architecture of proteinaceous assemblies from the peptide sequence.