From Fibers to Micelles Using Point-Mutated Amphiphilic Peptides

Schuster, T. B. and Ouboter, D. D. and Palivan, C. G. and Meier, W.. (2011) From Fibers to Micelles Using Point-Mutated Amphiphilic Peptides. Langmuir, 27 (8). pp. 4578-4584.

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Official URL: http://edoc.unibas.ch/dok/A6001625

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Biocompatible, self-assembled nanostructures are attracting ever more attention, in particular in aqueous media for biomedical applications. Here, we present the successful, solid-phase peptide synthesis (SPPS) and characterization of short amino acid sequences with amphiphilic character with the aim of gaining insight into their self-assembled, supramolecular structures. The peptide design includes three parts: (a) a charged lysine part (b) an acetylated lysine part, and (c) a constant hydrophobic rodlike helix, based on gramicidin A (gA). By stepwise replacement of free lysine (K) with acetylated lysine (X) we generated a library of a total of 10 peptides, Ac-Xg-gA and K(m)X(8-m)-gA (m ranging from 0 to 8). By using point mutations, we adjusted the degree of acetylation (DA) and thus the overall amphiphilicity of the peptides, which led to a change in the secondary structure in the aqueous environment from a beta-sheet to an a-helix. This transition generated a significant change in the morphology of the self-assembled structures from fibers to micelles. Two different regions were observed for the conformation of the hydrophilic part of the peptide: one region, a beta-sheet-like secondary structure, inducing fiber formation (high DA), the other an a-helical-like secondary structure, generating micelle formation (moderate and low DA). The micellar structures depended on the degree of acetylation, which influenced their critical micelle concentration (cmc). These morphology regions were determined by a combination of circular dichroism, dynamic light scattering, surface tension, and transmission electron microscopy, which allowed us to correlate the generated supramolecular architectures with the fine changes obtained by means of the point mutation strategy.
Faculties and Departments:05 Faculty of Science > Departement Chemie
05 Faculty of Science > Departement Chemie > Chemie > Makromolekulare Chemie (Meier)
UniBasel Contributors:Meier, Wolfgang P. and Palivan, Cornelia G
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Chemical Society
Note:Publication type according to Uni Basel Research Database: Journal article
Identification Number:
Last Modified:04 Jun 2018 11:47
Deposited On:08 Nov 2012 16:10

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