Critical Self-assembly Concentration of Bolaamphiphilic Peptides and Peptide Hybrids Determined by Fluorescence Measurements

Abstract

The study of the self-assembly properties of peptides and proteins is important for the understanding of molecular recognition processes and for the rational design of functional biomaterials. Novel bolaamphiphilic peptides and peptide hybrids incorporating non-natural aminoacids were designed around a model lysine/leucine-rich peptide with the intention to study their selfassembly behaviour. Steady-state fluorescence measurements using pyrene as fluorescent probe were adapted to the determination of the critical self-assembly concentrations (CSACs) of these amphiphilic peptides and peptide hybrids. Different experimental conditions were studied. The morphology of the peptide aggregates was evaluated by scanning electron microscopy (SEM). Concentration andpHhave been revealed to play a key role in the control of the process. Peptides presented different three-dimensional supramolecular arrangements that were correlated with their aminoacid compositions (specifically considering the presence of tyrosine and proline) and CSAC values.

Keywords: Peptide aggregation, self-assembly, critical self-assembly concentration, fluorescence, pyrene

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