Design of Phenylalanine-Containing Elastin-Derived Peptides Exhibiting Highly Potent Self-Assembling Capability

Abstract

In this study, we developed a series of Phe-containing elastin-derived peptide-analogs, (Phe-Pro-Gly-Val-Gly)n (n = 1-5) and analyzed their reversible coacervation properties. Compared to the native elastin-derived repeating peptide sequence ((Val-Pro-Gly-Val-Gly)10), one of the Phecontaining 5-mer repeating peptide sequences ((Phe-Pro-Gly-Val-Gly)5) clearly exhibited stronger coacervation properties. The coacervation of (Phe-Pro-Gly-Val-Gly)5 is nearly the same as that of polypeptides (Val-Pro-Gly-Val-Gly)n (n > 40). Although large molecular weights (>10,000 Da) are generally required for the coacervation of elastin-derived peptides, (Phe-Pro-Gly-Val-Gly)5 exhibited reversible coacervation properties despite its low molecular weight (MW = 2,305 Da). High performance liquid chromatography (HPLC) and circular dichroism (CD) analysis revealed that (Phe-Pro-Gly-Val-Gly)5 has high hydrophobicity and an ordered structure with a type II β-turn, which contributes to the strong coacervation ability of the peptide. In addition, (Phe-Pro-Gly-Val-Gly)5 exhibited an effective particle size distribution (60-70 nm) at body temperature (37°C) and a dispersed small particle size similar to that of the monomer peptides at low temperatures. These properties, along with its small size and simple design, render the peptide suitable for use in biomaterials, including drug-delivery carriers.

Dimerization effects on coacervation property of an elastin-derived synthetic peptide (FPGVG)5

“…The N-dimer spectrum showed a prominent negative band at 197 nm, a positive band at 220 nm and a minor negative band at 236 nm (Figure 4). These features are similar to the CD spectra of the (FPGVG) 5 monomer [11]. Furthermore, the CD measurements showed that the dimers exhibited reversible temperature-dependent spectral changes, although the degree of alteration was lower than that observed for the (FPGVG) 5 monomer [11].…”

“…In contrast, the (FPGVG) 5 monomer did not show any increase in turbidity under the same conditions (Figure 3a). Previous studies reported that this monomer requires a higher temperature (T t = 38.0°C) and at least 3× higher concentration (30 mg/ml) to consistently achieve coacervation (Figure 3b) [11]; coacervation was not always apparent at a concentration of 20 mg/ml. These results suggest that the dimerization of elastin-derived peptide analogs enhanced the coacervation ability of (FPGVG) 5 .…”

“…A sufficiently high (VPGVG) n repetition number (n > 40) is required for coacervation [7][8][9][10]. Recently, we developed the synthetic hydrophobic oligomers (IPGVG) n [7] and (FPGVG) n [11], and found that they exhibited coacervation at significantly lower repetition numbers (n = 5-7). Previous reports have shown that using dimeric peptides is a useful strategy for controlling the self-assembly process and stability of peptide-based supramolecular nanostructures [12,13].…”

Development of short and highly potent self‐assembling elastin‐derived pentapeptide repeats containing aromatic amino acid residues

“…Previously, we performed reversed-phase HPLC analyses for various elastin-derived peptides using an ODS (octadecylsilyl) column. From these results, a correlation between the coacervation property and the retention time was observed [17,18]. Therefore, we performed reversed-phase HPLC analyses for all peptides used in this study.…”

“…We have reported that an elastin-derived peptide analog, in which Val at position 1 in the representative elastin-derived sequence VPGVG was substituted by the more hydrophobic amino acid Ile [17], exhibited enhanced coacervation. Furthermore, the substitution by the aromatic amino acid Phe at position 1 revealed a more potent coacervation property than exhibited by the Ile-containing elastin-derived peptides [18]. Although the hydrophobicity of Phe is generally considered less than that of Ile [25], the Phe substitution led to a more enhanced coacervation potency than did the Ile substitution.…”