Simple Regulation of the Self-Assembling Ability by Multimerization of Elastin-Derived Peptide (FPGVG)_n Using Nitrilotriacetic Acid as a Building Block

Abstract

Elastin comprises hydrophobic repetitive sequences, such as Val-Pro-Gly-Val-Gly, which are thought to be important for the temperature-dependent reversible self-association (coacervation). Elastin and elastin-like peptides (ELPs), owing to their characteristics, are expected to be applied as base materials for the development of new molecular tools, such as drug-delivery system carrier and metal-scavenging agents. Recently, several studies have been reported on the dendritic or branching ELP analogues. Although the topological difference of the branched ELPs compared to their linear counterparts may lead to useful properties in biomaterials, the available information regarding the effect of branching on molecular architecture and thermoresponsive behavior of ELPs is scarce. To obtain further insight into the thermoresponsive behavior of branched ELPs, novel ELPs, such as nitrilotriacetic acid (NTA)−(FPGVG) n conjugates, that is, (NTA)-Fn analogues possessing 1−3 (FPGVG) n (n = 3, 5) molecule(s), were synthesized and investigated for their coacervation ability. Turbidity measurement of the synthesized peptide analogues revealed that (NTA)-Fn analogues showed strong coacervation ability with various strengths. The transition temperature of NTA-Fn analogues exponentially decreased with increasing number of residues. In the circular dichroism measurements, trimerization did not alter the secondary structure of each peptide chain of the NTA-Fn analogue. In addition, it was also revealed that the NTA-Fn analogue possesses one peptide chain that could be utilized as metal-scavenging agents. The study findings indicated that multimerization of short ELPs via NTA is a useful and powerful strategy to obtain thermoresponsive molecules.

Metal ion scavenging activity of elastin-like peptide analogues containing a cadmium ion binding sequence

“…The particle size measurement analyses indicated that the coacervation of AADAAC-F4 might follow a stepwise process in which sub-micron aggregates grow into micrometer-sized coacervates. Such a stepwise process is similar to that of the dendritic thermoresponsive ELP 55 and some strong coacervatable short ELPs that we reported earlier 49 – 51 . In addition, DLS measurements were carried out in the presence of Cd 2+ (Fig.…”

“…In addition, AADAAC-F4 can be readily recycled by simple treatment with an acidic solution and can be reused to collect Cd 2+ . Particle size distribution analysis indicated that AADAAC-F4 follows a stepwise self-association process involving the generation of sub-micron aggregates followed by coacervate maturation, which is similar to that observed for strong coacervatable short ELPs that we have previously reported 49 – 51 . Furthermore, microscopic analyses of AADAAC-F4 suggested that this peptide rapidly forms spherical particles several micrometers in diameter in the presence of Cd 2+ , implying that it can be easily separated from solution when used as a metal scavenging agent.…”

“…We found that phenylalanine-containing synthetic ELPs consisting of (FPGVG) n sequences exhibited strong coacervation ability at a significantly low number of repetitions (n = 5) 44 , whereas (VPGVG) n required a relatively high repetition number (n > 40) to exhibit coacervation ability 45 – 47 . Therefore, by mimicking such repetitive sequences, various ELP analogues composed of Xaa-Pro-Gly-Val-Gly (XPGVG where X = I, F, and W) pentapeptide repeats have been developed 44 , 47 – 51 . During these experimental studies, we discovered that nitrilotriacetic acid (NTA)-conjugated short ELP analogues could bind to several metal ions, such as copper or nickel 52 .…”

Flexible customization of the self‐assembling abilities of short elastin‐like peptide Fn analogs by substituting N‐terminal amino acids

“…The distribution of the particle size in F5-FnY, F5-F1Y/F21Y, and F5-F1X (X = Trp, Ala, and Cha) solution was analyzed by dynamic light scattering (DLS) measurement using a Zetasizer nano ZS (Malvern Instruments Ltd., Worcestershire, UK) in a measurement cell ZEN0112 (Malvern Instruments Ltd.). [53] The peptide sample solutions were prepared at a concentration of 10 mg/mL in phosphate buffer (27.4 mM Na 2 HPO 4 , 17.8 mM NaH 2 PO 4 , pH 7.4) and filtered using the Millex-LG filter (Merck Millipore) before measurement. DLS analysis was performed by increasing the temperature at 10 C intervals from 0 to 40 C and 5 to 45 C. Measurement duration was selected automatically.…”

“…[51] Based on this repetitive sequence, we developed various thermoresponsive peptides, including nonlinear ELPs or combinations with other functional sequences. [52][53][54][55][56][57] Short-chain ELPs are beneficial as mass production by simple chemical synthesis is practically feasible without reconstructing the expression plasmids that are required for long-chain ELPs. Moreover, these short-chain ELPs allow the regulation of their physicochemical properties by replacing any amino acids with other amino acids, including D-amino acids or unnatural amino acids, in the chemical synthetic process.…”