A Diphenylalanine Based Pentapeptide with Fibrillating Self-Assembling Properties

Abstract

Peptides and their related compounds can self-assemble into diverse nanostructures of different shapes and sizes in response to various stimuli such as pH, temperature or ionic strength. Here we report the synthesis and characterization of a lysozyme derived pentapeptide and its ability to build well-defined fibrillar structures. Lysozyme FESNF peptide fragment was synthesized by solid phase peptide synthesis using the Fmoc/t-Bu strategy, purified by analytical high-performance liquid chromatography (HPLC) and its molecular weight was confirmed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI–MS). Spectroscopic features of this pentapeptide were investigated by UV-visible spectroscopy and fluorimetry showing the pattern of marginal phenylalanine residues within the peptide sequence. Self-assembling properties were determined using atomic force microscopy (AFM), aggregation index and thioflavin T assay (ThT). FESNF generating fibrillar structures observed by AFM and aggregation propensity were primarily influenced by pH conditions. Moreover, the experimental data were confirmed by molecular dynamics simulation studies. The obtained fibrils will be used next to explore their potential to act as support material for medical and cosmetic application.

Self-Assembly of a Novel Pentapeptide into Hydrogelated Dendritic Architecture: Synthesis, Properties, Molecular Docking and Prospective Applications

“…Appropriate intermolecular alignment and interactions between side chains are required for a certain peptide conformation with the assembly of nanofibers into a hydrogel. As anticipated, in concordance with findings from a previous investigation [23], the presence of terminal PHE side chains (PHE1 and PHE5) in the peptide's structure facilitates their engagement in π-π stacking interactions. Such interactions are recognized for imparting order and directionality to the peptide self-assembly into fibril-like structures, playing a pivotal role in shaping the final 3D architecture [23,57].…”

“…Moreover, scrutiny of the tandem MS spectra reveals that the equitable distribution of aromatic residues along the peptide backbone induces fragmentation at all amide bonds. This diverges from our earlier investigations, wherein the mutant peptide FESNY-NH 2 characterized by aromatic residues solely at the termini exhibited a marked predilection for fragmentation in those regions [33]. The inclusion of phenylalanine and tyrosine residues, endowed with a relatively high electron density, is conjectured to facilitate fragmentation by promoting charge localization and augmenting susceptibility to dissociation processes in tandem MS spectra [34].…”

“…It is well known that within physiological parameters (pH 7.4), the tyrosine residue likely retains its neutral state, facilitating pivotal interactions for the initiation of fibrillogenesis [47]. When juxtaposed with the previously studied peptide (FESNF-NH2) under analogous pH conditions [23], the introduction of tyrosine led to morphological changes for FEYNF-NH2. Hence, although the formation of fibrils was absolutely absent in the case of the initial FESNF-NH2 peptide at pH 7.4, and the newly synthetized FEYNF-NH2 peptide possesses a distinctive capability at the physiological pH: the formation of dendritic-like fibrils (Figure 6).…”

“…Certain peptides have the inherent capability to undergo self-assembly, leading to the formation of gels characterized by adjustable properties under specific environmental conditions [12]. In a previous study, we demonstrated the propensity of a pentapeptide inspired by the hen egg-white lysozyme, specifically, FESNF (where F-phenylalanyl, E-glutamyl, S-seryl, and N-asparaginyl), to self-assemble into ordered and dense fibrils [23]. Given the fact that aromatic amino acid side chains (e.g., phenylalanine, tyrosine, tryptophan, and histidine) are likely to participate in π-stacking interactions [24], we suggested substituting the serine (S) in the FESNF peptide with the aromatic amino acid tyrosine (Y).…”

Diversity of Bioinspired Hydrogels: From Structure to Applications

“…On the other hand, peptides are relatively easily synthesized and, in some cases, manufactured. As building blocks for various biomaterials, peptides have several advantages: they are composed of nonpolar, polar, or charged amino acids, allowing a certain level of prediction of self-assembly properties through the meticulous selection of the peptide sequence [20]. As endogenous molecules, they reduce the risk of adverse effects.…”