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Title: Interactions of natural and synthetic self-assembling peptides with phospholipid monolayers
Author: Protopapa, Elisabeth
ISNI:       0000 0004 2681 5304
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2008
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Rationally designed self-assembling f3-sheet fonning peptides have been previously shown to undergo nucleated one-dimensional self-assembly above a critical concentration in solution, from monomeric random coil into a hierarchy of well-defined f3-sheet . . nanotapes, ribbons and fibrils. The interest in the application of self-assembling peptides in m~dicine e.g. tissue engineering, and in bios~nsors dictates the need to correlate peptide molecular structure with membrane nanotoxicity. Here a series of parameters are examined that could affect the peptide interactions with phospholipid monolayersusing electrochemical techniques on a model DOPC-Hg supported system. These parameters are namely peptide aggregation state, polarity, net charge, applied voltage and amphiphilicity. For this study a total of 16 systematically altered self-assembling tape-forming peptides have been employed. It is ,shown _ that in the absence of applied voltage, amphiphilic peptides, with aromatic amino acids, a zero net charge and in monomeric rather than aggregated state in solution, have the highest propensIty to bind to DOPC. monolayers and give rise to discrete conducting structures. Positively charged amphiphilic peptides interact more strongly with Dope than negatively charged ones, whilst polar peptides show little interaction with DOPC. Applied negative voltage across the lipid layer drives the binding ofamphiphilic and polar positively charged peptides to the lipid layer, however such - .peptides are less able to undergo self-assembly into pore-like structures in the lipid environment. Introduction of serine amino acid from the choice of the available polar I amino acids in the peptide primary seq~ence facilitates significantly the peptide-DOPC interaction. This class of pep tides are shown to be considerably less membrane-disruptive compared to antimicrobial peptides. This research provides not only a greater insight into the rational design of new peptide-based biomaterials but also a further understanding of the interactions of natural antimicrobial and amyloid-forming peptides with biological membranes.
Supervisor: Not available Sponsor: Not available
Qualification Name: Not available Qualification Level: Doctoral
EThOS ID:  DOI: Not available