Self-assembly of PEGylated tetra-phenylalanine derivatives: structural insights from solution and solid state studies

Diaferia, Carlo; Mercurio, Flavia Anna; Giannini, Cinzia; Sibillano, Teresa; Morelli, Giancarlo; Leone, Marilisa; Accardo, Antonella

doi:10.1038/srep26638

Cited by 31 publications

(36 citation statements)

References 41 publications

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“…Our results indicate that initially the peptide organizes into nanofibers, as is frequently observed in highly aromatic F‐based peptides . After this stage, which is dominated by peptide⋅⋅⋅peptide interactions, a very large variety of polymorphs can be subsequently formed by regulating the strength and nature of peptide⋅⋅⋅surface interactions.…”

Section: Introductionsupporting

confidence: 62%

Surface Mediated Hierarchical Assemblies of Highly Hydrophobic Phenylalanine‐Based Peptides

et al. 2017

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We report the noticeable control exerted by the surface in the self‐assembly of a highly hydrophobic triphenylalanine peptide with fluorenyl functionalities blocking the two ends. The remarkable differences observed among the polymorphic hierarchical assemblies obtained onto silanized glass, scratched glass, stainless steel, exfoliated mica, silicon wafer, carbon, polytetrafluoroethylene, plasma‐functionalized, polystyrene and nitrocellulose substrates are consequence of the balance between peptide⋅⋅⋅peptide and peptide⋅⋅⋅surface interactions. This balance is greatly influenced by the surface characteristics, as defined by the wettability (hydrophobicity or hydrophilicity) and roughness (degree of flatness and regularity). Furthermore, very stable dendritic structures, in which primary frameworks nucleated from the center grow according to a 4‐fold pseudo‐symmetry branching, have been obtained onto hydrophilic treated polystyrene.

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Section: Introductionsupporting

confidence: 62%

Surface Mediated Hierarchical Assemblies of Highly Hydrophobic Phenylalanine‐Based Peptides

et al. 2017

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“…Finally, for the same equatorial β‐sheet reflection, we estimated the full‐width‐at‐half‐maximum (FWHM) along the azimuth Φ angle (i.e., along the diffraction circle): FWHM(PEG 8 )=FWHM(PEG 12 )=54±2°, FWHM(PEG 18 )=62±2°, and FWHM(PEG 24 )>180° (see Figure g). These values reflect a clear increase in fiber disorder, which is a maximum for the PEG 24 sample, for which it is not possible to identify any preferred orientation direction of the fiber. We exclude that fiber disorder can be attributed to PEG crystallization.…”

Section: Resultsmentioning

confidence: 93%

Structural Characterization of PEGylated Hexaphenylalanine Nanostructures Exhibiting Green Photoluminescence Emission

Diaferia

Sibillano

Altamura

et al. 2017

Chemistry A European J

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Peptides containing aromatic residues are known to exhibit spontaneous phenomena of supramolecular organization into ordered nanostructures (NSs). In this work we studied the structural behavior and optoelectronic properties of new biocompatible materials obtained by the self-assembly of a series of hexaphenylalanines (F6) modified at the N terminus by a PEG chain of different lengths. PEG -F6, PEG -F6, and PEG -F6 peptides were synthesized by coupling sequentially two, three, or four units of amino-carboxy-PEG blocks, each one containing six oxyethylene repetitions. Changes in the length and composition of the PEG chain were found to modulate the structural organization of the phenylalanine-based nanostructures. An increase in the self-aggregation tendency was observed with longer PEG chains, whereas, independently of the PEG length, the peptide NSs display cross-β-like secondary structures with an antiparallel β-strand arrangement. WAXS/GIWAXS diffraction patterns indicate a progressive decrease in fiber order along the series. All the PEG-F6 derivatives present blue photoluminescent (PL) emission at 460 nm, with the adduct with the longest PEG chain (PEG -F6) showing an additional green emission at 530 nm.

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“…The 2D data were integrated along these orthogonal axes and the corresponding 1D profiles, shown in Figure (lower part) as red (meridional) and black (equatorial) profiles, present almost the same reflections. The 0–3 labeled meridional and equatorial peaks are summarized in Table , in which the diffraction peak at q =1.29–1.33 Å −1 ( d =4.7–4.9 Å) can be attributed to the distance between adjacent peptide backbones organized into β‐strands along the fiber axis and the diffraction peak at q =0.49–0.3 Å −1 ( d =11.9–12.8 Å) to the distance between two distinct β‐sheets . It is worth noting that the reflection at 4.7 Å coincides with a strong reflection expected from crystalline PEG .…”

Section: Resultsmentioning

confidence: 96%

Amyloid‐Like Fibrillary Morphology Originated by Tyrosine‐Containing Aromatic Hexapeptides

Diaferia

Balasco

Sibillano

et al. 2018

Chemistry A European J

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Phenylalanine-based nanostructures have attracted the attention of the material science community for their functional properties. These properties strongly depend on the hierarchic organization of the nanostructure that in turn can be finely tuned by punctual chemical modifications of the building blocks. Herein, we investigate how the partial or the complete replacement of the Phe residues in PEG -(Phe) (PEG -F6) with tyrosines to generate PEG -(Phe-Tyr) (PEG -(FY)3) or PEG -(Tyr) (PEG -Y6) affects the structural/functional properties of the nanomaterial formed by the parental compound. Moreover, the effect of the PEG derivatization was evaluated through the characterization of the peptides without the PEG moiety (Tyr) (Y6) and (Phe-Tyr) ((FY)3). Both PEG -Y6 and PEG -(FY)3 can self-assemble in water at micromolar concentrations in β-sheet-rich nanostructures. However, WAXS diffraction patterns of these compounds present significant differences. PEG -(FY)3 shows a 2D WAXS oriented fiber diffraction profile characterized by the concomitant presence of a 4.7 Å meridional and a 12.5 Å equatorial reflection that are generally associated with cross-β structure. On the other hand, the pattern of PEG -Y6 is characterized by the presence of circles typically observed in the presence of PEG crystallization. Molecular modeling and dynamics provide an atomic structural model of the peptide spine of these compounds that is in good agreement with WAXS experimental data. Gelation phenomenon was only detected for PEG -(FY)3 above a concentration of 1.0 wt % as confirmed by storage (G'≈100 Pa) and loss (G''≈28 Pa) moduli in rheological studies. The cell viability on CHO cells of this soft hydrogel was certified to be 90 % after 24 hours of incubation.

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Self-assembly of PEGylated tetra-phenylalanine derivatives: structural insights from solution and solid state studies

Cited by 31 publications

References 41 publications

Surface Mediated Hierarchical Assemblies of Highly Hydrophobic Phenylalanine‐Based Peptides

Surface Mediated Hierarchical Assemblies of Highly Hydrophobic Phenylalanine‐Based Peptides

Structural Characterization of PEGylated Hexaphenylalanine Nanostructures Exhibiting Green Photoluminescence Emission

Amyloid‐Like Fibrillary Morphology Originated by Tyrosine‐Containing Aromatic Hexapeptides

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