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

Abstract

The development of simple and safe methods for recovering environmental pollutants, such as heavy metals, is needed for sustainable environmental management. Short elastin-like peptide (ELP) analogues conjugated with metal chelating agents are considered to be useful as metal sequestering agents as they are readily produced, environment friendly, and the metal binding domain can be selected based on any target metal of interest. Due to the temperature dependent self-assembly of ELP, the peptide-based sequestering agents can be transformed from the solution state into the particles that chelate metal ions, which can then be collected as precipitates. In this study, we developed a peptide-based sequestering agent, AADAAC-(FPGVG)4, by introducing the metal-binding sequence AADAAC on the N-terminus of a short ELP, (FPGVG)4. In turbidity measurements, AADAAC-(FPGVG)4 revealed strong self-assembling ability in the presence of metal ions such as Cd2+ and Zn2+. The results from colorimetric analysis indicated that AADAAC-(FPGVG)4 could capture Cd2+ and Zn2+. Furthermore, AADAAC-(FPGVG)4 that bound to metal ions could be readily recycled by treatment with acidic solution without compromising its metal binding affinity. The present study indicates that the fusion of the metal-binding sequence and ELP is a useful and powerful strategy to develop cost-effective heavy metal scavenging agents with low environmental impacts.

Development of truncated elastin-like peptide analogues with improved temperature-response and self-assembling properties

“…9 B, although the Zn 2+ concentration in the supernatant was also decreased by treatment with this peptide, the removal efficiency was lower than that of Cd 2+ . This result was similar to our previous study related to AADAAC-(FPGVG) 4 45 . Our previous study implied that most of the removed metal ions were incorporated into the aggregates formed by the peptides, rather than captured by AADAAC sequence.…”

“…In other words, this result suggests that the self-assembly ability of this peptide was enhanced by the presence of Cd 2+ . This characteristic of AADAAC-(FPGV) 4 was similar to that of AADAAC-(FPGVG) 4 , which we previously reported 45 . Subsequently, to verify whether this peptide can be used as a metal recovery agent at a lower peptide concentration, turbidity measurement using a low-concentration peptide solution (0.5 mg/mL, 0.236 mM) was performed.…”

“…This hexapeptide sequence strongly and selectively binds to cadmium above pH 6.0, whereas this peptide releases metal ions below pH 4.0 51 . Recently, we reported that an ELP analogue, AADAAC-(FPGVG) 4 , which was prepared by conjugating an AADAAC sequence at the N -terminus of (FPGVG) 4 , can be utilized as a metal scavenger exhibiting high affinity for cadmium ions 45 . In the present study, AADAAC-(FPGV) 4 was prepared using (FPGV) 4 , which shows stronger coacervation activity than F4 and investigated its properties as a shorter and easy-to-synthesize metal scavenging agent (Table S1 and Fig.…”

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

“…The light field observation was performed using a Leica DM IL LED (Leica Microsystems CMS, Wetzlar, Germany) equipped with HI PLAN 40Â (Leica Microsystems CMS) and HC PLAN 10Â (Leica Microsystems CMS). [52,54,55] The peptide sample solutions were prepared at a concentration of 10 mg/mL with phosphate buffer and applied on a glass slide. Sample imaging was performed at various temperatures between 4 and 60 C by using Thermo Plate TP-CHSQM (Tokai Hit Co., Ltd., Shizuoka, Japan).…”

“…[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.…”