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9 pages, 1867 KiB

Open AccessArticle

Development of a CaCO₃ Precipitation Method Using a Peptide and Microwaves Generated by a Magnetron

by Fumihiro Kayamori, Hiroyuki Togashi, Natsumi Endo, Makoto Ozaki, Kan Hirao, Yonejiro Arimoto, Ryuji Osawa, Takaaki Tsuruoka, Takahito Imai, Kin-ya Tomizaki, Tomohiro Umetani, Nobuhiro Nakanishi and Kenji Usui

Processes 2024, 12(7), 1327; https://doi.org/10.3390/pr12071327 - 26 Jun 2024

Viewed by 1693

Abstract

Microwave applications, such as microwave ovens and mobile phones, are ubiquitous and indispensable in modern society. As the utilization of microwave technology is becoming more widespread, the effects of microwaves on living organisms and physiological processes have received increased attention. This study aimed [...] Read more.

Microwave applications, such as microwave ovens and mobile phones, are ubiquitous and indispensable in modern society. As the utilization of microwave technology is becoming more widespread, the effects of microwaves on living organisms and physiological processes have received increased attention. This study aimed to investigate the effects of microwaves on calcium carbonate biomineralization as a model biochemical process. A magnetron oscillator was used to generate 2450 MHz microwaves because magnetrons are relatively inexpensive and widespread. We conducted transmission electron microscopy (TEM), atomic force microscopy (AFM), TEM-electron energy-loss spectroscopy (EELS), dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC) measurements to analyze the calcium carbonate precipitates. Our findings showed the formation of string-like precipitates of calcium carbonate upon microwave irradiation from one direction, similar to those obtained using a semiconductor oscillator, as reported previously. This implied that the distribution of the frequency had little effect on the morphology. Furthermore, spherical precipitates were obtained upon microwave irradiation from two directions, indicating that the morphology could be controlled by varying the direction of microwave irradiation. Magnetrons are versatile and also used in large-scale production; thus, this method has potential in medical and industrial applications. Full article

(This article belongs to the Special Issue The Amazing World of Peptide Engineering)

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14 pages, 2029 KiB

Open AccessArticle

Pyrene-Modified Cyclic Peptides Detect Cu²⁺ Ions by Fluorescence in Water

by Yuhi Maekawa, Sora Sakura, Yuji Furutani, Rento Fujihara, Hisashi Sugime, Takashi Ohtsuki and Mizuki Kitamatsu

Processes 2024, 12(4), 746; https://doi.org/10.3390/pr12040746 - 7 Apr 2024

Cited by 2 | Viewed by 1193

Abstract

The detection of metal ions is an option for maintaining water quality and diagnosing metal ion-related diseases. In this study, we successfully detected metal ions using fluorescent peptides in water. First, we prepared seven linear (L1–L7) and seven cyclic [...] Read more.

The detection of metal ions is an option for maintaining water quality and diagnosing metal ion-related diseases. In this study, we successfully detected metal ions using fluorescent peptides in water. First, we prepared seven linear (L1–L7) and seven cyclic (C1–C7) peptides containing two pyrenyl (Pyr) units and assessed the response to various metal ions by fluorescence. The results indicated that C1, which contains a hexameric cyclic peptide moiety consisting of Pyr and Gly units, did not show a fluorescent response to metal ions, while the linear L1 corresponding to C1 showed a response to Cu²⁺, but its selectivity was found to be poor through a competition assay for each metal ion. We then assessed C2–C7 and L2–L7, in which Gly was replaced by His units at various positions in the same manner. The results showed that C2–C7 responded to Cu²⁺ in a manner dependent on the His position. Additionally, superior selectivity was observed in C7 through a competition assay. These results demonstrate that the structural restriction of peptides and the sequence affect the selective detection of Cu²⁺ and reveal that peptides with an appropriate structure can accomplish the fluorescent detection of Cu²⁺ specifically. Full article

(This article belongs to the Special Issue The Amazing World of Peptide Engineering)

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9 pages, 1825 KiB

Open AccessFeature PaperArticle

Reaction of Chloroacetyl-Modified Peptides with Mercaptoundecahydrododecaborate (BSH) Is Accelerated by Basic Amino Acid Residues in the Peptide

by Mizuki Kitamatsu, Ken Inoue, Naoki Yamagata and Hiroyuki Michiue

Processes 2022, 10(11), 2200; https://doi.org/10.3390/pr10112200 - 26 Oct 2022

Cited by 3 | Viewed by 1919

Abstract

We assessed a reactivity of chloroacetyl-modified tripeptides consisting of various amino acid residues (Cl-3X) and mercaptoundecahydrododecaborate (BSH) by converting Cl-3X to its reactant (BS-3X). We showed that the Cl-3X consisting of basic amino acid residues (e.g., Arg) reacted with BSH effectively and its [...] Read more.

We assessed a reactivity of chloroacetyl-modified tripeptides consisting of various amino acid residues (Cl-3X) and mercaptoundecahydrododecaborate (BSH) by converting Cl-3X to its reactant (BS-3X). We showed that the Cl-3X consisting of basic amino acid residues (e.g., Arg) reacted with BSH effectively and its conversion decreased as the number of Arg residues in the Cl-3X decreased. Furthermore, a reactivity of the peptides with introduction of an alkyl linker between the triarginine and the chloroacetyl group (Cl-Cn-3R) with BSH decreased with increasing alkyl linker length. These results indicate that an electrostatic attraction of positively charged amino acid residues in the tripeptides and negatively charged BSH causes BSH to gather in a vicinity of the chloroacetyl group, resulting in an accelerated reaction. This work should aid a development of new boron agents using BSH in boron neutron capture therapy. Full article

(This article belongs to the Special Issue The Amazing World of Peptide Engineering)

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12 pages, 2119 KiB

Open AccessArticle

Cell Behavior on Peptide-Immobilized Substrate with Cell Aggregation Inducing Property

by Ikumi Amimoto, Rino Watanabe and Yoshiaki Hirano

Processes 2022, 10(9), 1779; https://doi.org/10.3390/pr10091779 - 5 Sep 2022

Cited by 1 | Viewed by 1790

Abstract

Cell aggregates have been applied in various fields such as regenerative medicine and drug toxicity testing. We have shown that H-(Lys-Pro)₁₂-OH (KP24), a repeating sequence of lysine (Lys) and proline (Pro), induces uniformly sized cell aggregates simply by its presence in [...] Read more.

Cell aggregates have been applied in various fields such as regenerative medicine and drug toxicity testing. We have shown that H-(Lys-Pro)₁₂-OH (KP24), a repeating sequence of lysine (Lys) and proline (Pro), induces uniformly sized cell aggregates simply by its presence in cell suspension. In this study, we considered that this peptide could be applied to a three-dimensional culture substrate that can induce uniform cell aggregates by immobilizing it on the substrate. Therefore, mouse fibroblasts (L929) were seeded on KP24-immobilized glass substrates and cell behavior was observed. We also seeded human-derived cells, namely, human mesenchymal stem cells (hMSC), on KP24-immobilized substrates and characterized their cell assemblies. Furthermore, KP24 was chemically immobilized on the substrate surface, which allowed us to trace the mechanism of KP24–cell interaction. As a mechanism analysis of the cell aggregation ability of KP24, we investigated whether KP24 interacts with the cell surface without being incorporated into the cell. Full article

(This article belongs to the Special Issue The Amazing World of Peptide Engineering)

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16 pages, 2503 KiB

Open AccessArticle

Development of Antibody-like Proteins Targeting the Oncogenic Ser/Thr Protein Phosphatase PPM1D

by Megumi Ikeura, Hiroto Tashiro, Yuka Yamagata, Hikaru Saito, Tamaki Kobayashi, Masataka Mizunuma, Kazuki Yamazaki, Keisuke Baba, Kazuhiro Furukawa and Yoshiro Chuman

Processes 2022, 10(8), 1501; https://doi.org/10.3390/pr10081501 - 29 Jul 2022

Cited by 2 | Viewed by 2709

Abstract

PPM1D, a protein Ser/Thr phosphatase, is overexpressed in various cancers and functions as an oncogenic protein by inactivating the p53 pathway. Therefore, molecules that bind PPM1D are expected to be useful anti-cancer agents. In this study, we constructed a phage display library based [...] Read more.

PPM1D, a protein Ser/Thr phosphatase, is overexpressed in various cancers and functions as an oncogenic protein by inactivating the p53 pathway. Therefore, molecules that bind PPM1D are expected to be useful anti-cancer agents. In this study, we constructed a phage display library based on the antibody-like small molecule protein adnectin and screened for PPM1D-specific binding molecules. We identified two adnectins, PMDB-1 and PMD-24, that bind PPM1D specific B-loop and PPM1D430 as targets, respectively. Specificity analyses of these recombinant proteins using other Ser/Thr protein phosphatases showed that these molecules bind to only PPM1D. Expression of PMDB-1 in breast cancer-derived MCF-7 cells overexpressing endogenous PPM1D stabilized p53, indicating that PMDB-1 functions as an inhibitor of PPM1D. Furthermore, MTT assay exhibited that MCF-7 cells expressing PMDB-1 showed inhibition of cell proliferation. These data suggest that the adnectin PMDB-1 identified in this study can be used as a lead compound for anti-cancer drugs targeting intracellular PPM1D. Full article

(This article belongs to the Special Issue The Amazing World of Peptide Engineering)

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11 pages, 3307 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Adjusting the Structure of a Peptide Nucleic Acid (PNA) Molecular Beacon and Promoting Its DNA Detection by a Hybrid with Quencher-Modified DNA

by Hajime Shigeto, Takamasa Kishi, Koki Ishii, Takashi Ohtsuki, Shohei Yamamura and Mizuki Kitamatsu

Processes 2022, 10(4), 722; https://doi.org/10.3390/pr10040722 - 8 Apr 2022

Cited by 1 | Viewed by 2641

Abstract

In this study, we performed an elaborate adjustment of the structure of peptide nucleic acid (PNA) molecular beacons as probes for detecting nucleic acids. We synthesized the PNA beacons with various numbers of Glu, Lys, and dabcyl (Dab) quenchers in them, and we [...] Read more.

In this study, we performed an elaborate adjustment of the structure of peptide nucleic acid (PNA) molecular beacons as probes for detecting nucleic acids. We synthesized the PNA beacons with various numbers of Glu, Lys, and dabcyl (Dab) quenchers in them, and we investigated their fluorescence changes (F_1/1/F₀) with and without full-match DNA. As the numbers of Glu/Lys or Dab increased, the F_1/1/F₀ tended to decrease. Among the different beacons, the PNA beacon with one Glu and one Lys (P1Q1) showed the largest F_1/1/F₀. On the other hand, a relatively large F_1/1/F₀ was obtained when the number of Glu/Lys and the number of Dab were the same, and the balance between the numbers of Glu/Lys and Dab seemed to affect the F_1/1/F₀. We also investigated the DNA detection by the prehybrid of P1Q1, which consists of the T790M base sequence, [P1Q1(T790M)], with quencher-modified DNA (Q-DNA). We examined the DNA detection with single-base mismatch by P1Q1(T790M), and we clarified that there was difficulty in detecting the sequence with P1Q1 alone, but that the sequence was successfully detected by the prehybrid of P1Q1 with the Q-DNA. Full article

(This article belongs to the Special Issue The Amazing World of Peptide Engineering)

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16 pages, 2335 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Miniaturization of Anthracene-Containing Nonapeptides for Selective Precipitation/Recovery of Metallic Gold from Aqueous Solutions Containing Gold and Platinum Ions

by Kin-ya Tomizaki, Tatsuki Tonoda, Shungo Teramura, Haruka Okazaki, Takahito Imai and Masahiro Asano

Processes 2021, 9(11), 2010; https://doi.org/10.3390/pr9112010 - 10 Nov 2021

Cited by 1 | Viewed by 1792

Abstract

The separation and recovery of noble metals is increasingly of interest, in particular the recovery of gold nanocrystals, which have applications in medicine and industry. Typically, metal recovery is performed using liquid–liquid extraction or electrowinning. However, it is necessary to develop noble metal [...] Read more.

The separation and recovery of noble metals is increasingly of interest, in particular the recovery of gold nanocrystals, which have applications in medicine and industry. Typically, metal recovery is performed using liquid–liquid extraction or electrowinning. However, it is necessary to develop noble metal recovery systems providing high selectivity in conjunction with a one-pot setup, ready product recovery, and the use of dilute aqueous solutions. In prior work, our group developed a selective gold recovery process using peptides. This previous research showed that RU065, a nonapeptide containing an anthracene moiety (at a concentration of 2.0 × 10⁻⁴ M), is capable of selective reduction of HAuCl₄ to recover gold from a solution of HAuCl₄ and H₂PtCl₆, each at 5.0 × 10⁻⁵ M. However, peptide molecules are generally costly to synthesize, and therefore it is important to determine the minimum required structural features to design non-peptide anthracene derivatives that could reduce operational costs. In this study, we used RU065 together with 23 of its fragment peptides and investigated the selective precipitation/recovery of metallic gold. RU065_4–8, a fragment peptide comprising five amino acid residues (having two lysine, one L-isoleusine, and one L-alanine residue (representing six amide groups) along with an L-2-anthrylalanine residue) provided an Au/Pt atomic ratio of approximately 8, which was comparable to that for the full-length original RU065. The structural features identified in this study are expected to contribute to the design of non-peptide anthracene derivatives for low-cost, one-pot selective gold recovery. Full article

(This article belongs to the Special Issue The Amazing World of Peptide Engineering)

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Review

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14 pages, 4658 KiB

Open AccessFeature PaperReview

Non-Classical Circularly Polarized Luminescence Control of Peptide Luminophore Based on Precise Chiral Space Control

by Yoshitane Imai and Mizuki Kitamatsu

Processes 2023, 11(9), 2778; https://doi.org/10.3390/pr11092778 - 17 Sep 2023

Cited by 2 | Viewed by 1298

Abstract

Light that rotates in a circular spiral when viewed from the front is known as circularly polarized luminescence (CPL), and can be divided into two types, namely, left- and right-rotating light. To emit both left- and right-rotating CPLs, two types of optically active [...] Read more.

Light that rotates in a circular spiral when viewed from the front is known as circularly polarized luminescence (CPL), and can be divided into two types, namely, left- and right-rotating light. To emit both left- and right-rotating CPLs, two types of optically active luminophores, namely, enantiomer D- and L-bodies, are generally required. This mini-review mainly discusses our latest study on CPL properties via the control of the pyrene ring as the luminescent unit incorporated into chiral peptides. In this study, optically active peptide–pyrene organoluminescent materials that emit CPL were synthesized by combining a peptide as a frame and two pyrene rings as a luminescent unit. By adjusting the interpyrene distance, external conditions, and absolute chiral configuration (D- or L-configuration), the chiral spatial configuration of the luminescent pyrene ring was precisely controlled. Consequently, the direction of CPL rotation from pyrenylalanine-containing peptides with the same configuration was successfully controlled. Full article

(This article belongs to the Special Issue The Amazing World of Peptide Engineering)

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24 pages, 14658 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Helical Foldamers and Stapled Peptides as New Modalities in Drug Discovery: Modulators of Protein-Protein Interactions

by Keisuke Tsuchiya, Takashi Kurohara, Kiyoshi Fukuhara, Takashi Misawa and Yosuke Demizu

Processes 2022, 10(5), 924; https://doi.org/10.3390/pr10050924 - 6 May 2022

Cited by 13 | Viewed by 4303

Abstract

A “foldamer” is an artificial oligomeric molecule with a regular secondary or tertiary structure consisting of various building blocks. A “stapled peptide” is a peptide with stabilized secondary structures, in particular, helical structures by intramolecular covalent side-chain cross-linking. Helical foldamers and stapled peptides [...] Read more.

A “foldamer” is an artificial oligomeric molecule with a regular secondary or tertiary structure consisting of various building blocks. A “stapled peptide” is a peptide with stabilized secondary structures, in particular, helical structures by intramolecular covalent side-chain cross-linking. Helical foldamers and stapled peptides are potential drug candidates that can target protein-protein interactions because they enable multipoint molecular recognition, which is difficult to achieve with low-molecular-weight compounds. This mini-review describes a variety of peptide-based foldamers and stapled peptides with a view to their applications in drug discovery, including our recent progress. Full article

(This article belongs to the Special Issue The Amazing World of Peptide Engineering)

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