Alpha helical surfactant-like peptides self-assemble into pH-dependent nanostructures
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2021-03-21
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en
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9
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Soft Matter, Volume 17, issue 11, pp. 3096-3104
Abstract
A designed surfactant-like peptide is shown, using a combination of cryogenic-transmission electron microscopy and small-angle X-ray scattering, to have remarkable pH-dependent self-assembly properties. Peptide Arg3-Leu12(R3L12) forms a network of peptide nanotubes at pH 9 and below. These are associated with α-helical conformation in a “cross-α” nanotube structure, in which peptide dimers lie perpendicular to the nanotube axis, with arginine coated inner and outer nanotube walls. In contrast, this peptide forms decorated vesicular aggregates at higher pH values, close to the pKaof the arginine residues. These structures are associated with a loss of α-helical order as detected through X-ray scattering, circular dichroism and FTIR spectroscopy, the latter technique also revealing a loss of ordering of leucine side chains. This suggests a proposed model for the decorated or patchy vesicular structures that comprises disordered peptide as the matrix of the membrane, with small domains of ordered peptide dimers forming the minority domains. We ascribe this to a lipid-raft like phase separation process, due to conformational disordering of the leucine hydrophobic chains. The observation of the self-assembly of a simple surfactant-like peptide into these types of nanostructure is remarkable, and peptide R3L12shows unique pH-dependent morphological and conformational behaviour, with the potential for a range of future applications.Description
Funding Information: The work of IWH and VC was supported by EPSRC Platform grant EP/L020599/1. We thank the ESRF for the award of beamtime for SAXS on ID02 (ref. SC-4981) and Thomas Zinn and Theyencheri Narayanan for performing the measurements. Publisher Copyright: © The Royal Society of Chemistry 2021. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.
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Castelletto, V, Seitsonen, J, Ruokolainen, J & Hamley, I W 2021, ' Alpha helical surfactant-like peptides self-assemble into pH-dependent nanostructures ', Soft Matter, vol. 17, no. 11, pp. 3096-3104 . https://doi.org/10.1039/d0sm02095h