Kousuke Tsuchiya

Polypeptides inspired by the natural functional and structural proteins present in living systems are promising materials for various fields in terms of their versatile functionality and physical properties. Designing and synthesizing mimetic sequences of specific peptide motifs in proteins are important for exploring the functionality of natural proteins. Chemoenzymatic polymerization, which utilizes aminolysis (i.e., the reverse reaction of hydrolysis catalyzed by proteases), is a useful techn

A novel thermally stable and low dielectric poly(binaphthylene ether) (2) has been developed. Polymer 2 was easily prepared by oxidative coupling polymerization of 2,2‘-bis(1-naphthyloxy)-1,1‘-binaphthyl (1) with FeCl3 as an oxidant. This polymerization produced regiocontrolled polymer 2 with a number-average molecular weight of 14 000 Da and a molecular weight distribution of 3.3. The 5% weight loss and glass transition temperatures of polymer 2 were 520 and 301 °C, respectively. The dielectric

ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTSynthesis of a Novel Poly(binaphthylene ether) Containing Trifluoromethyl Groups with a Low Dielectric ConstantKousuke Tsuchiya, Yuji Shibasaki, Masahiro Aoyagi, and Mitsuru UedaView Author Information Department of Organic and Polymeric Materials, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552, Japan, and National Institute of Advanced Industrial Science and Technology(AIST), Tsukuba

Polypeptides containing 2-aminoisobutyric acid (Aib) units as an unnatural amino acid residue were synthesized by papain-catalyzed chemoenzymatic polymerization of a tripeptide ethyl ester l-Ala-Aib-l-Ala-OEt in an aqueous medium. The Aib-containing polypeptide adopted an α-helix conformation in both the solid and solution phases, which was induced by the periodic Aib residue.

Introducing exogenous genes into plant cells is essential for a wide range of applications in agriculture and plant biotechnology fields. Cationic peptide carriers with cell-penetrating and DNA-binding domains successfully deliver exogenous genes into plants. However, their cell-penetrating activity may be attenuated by undesired electrostatic interactions between the cell-penetrating peptide (CPP) domain and DNA cargo, resulting in limited gene delivery efficiency. Here, we developed the block

Novel multiblock polypeptides with a structure similar to the unique sequence observed in spider silk proteins (spidroins) were synthesized via a two-step chemical synthesis method, that is, chemoenzymatic polymerization, using papain followed by postpolycondensation. Two types of polypeptide fragments were prepared by chemoenzymatic polymerization: polyalanine as a hard block, which forms β-sheets in the spider silk fibers, and poly(glycine-<i>random</i>-leucine) as a soft block. These two frag

Owing to their diverse functions and tunable physicochemical properties, peptides are promising alternatives to the conventional gene delivery tools that are available for plant systems. However, peptide-mediated gene delivery is limited by low transfection efficiency in plants because of the insufficient cytosolic translocation of DNA cargo. Here, we report a dual peptide-based gene delivery system for the efficient transfection of plant callus cells. This system is based on the combination of

An appropriate modification technique for silk materials is needed to effectively improve their physical properties for specific applications. A telechelic-type polyalanine (T-polyA) was synthesized by papain-catalyzed polymerization as a novel reinforcing agent for silk materials. A silk fibroin obtained from Bombyx mori was homogeneously doped with T-polyA, and casting a solution of silk fibroin and T-polyA in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) resulted in a robust and transparent film.

The delivery of DNA to plants is crucial for enhancing their ability to produce valuable compounds and adapt to climate change. Peptides can provide a versatile tool for delivering DNA to a specific target organelle in various plant species without the use of specialized equipment. However, peptide-mediated DNA delivery suffers from endosomal entrapment and subsequent vacuolar degradation of the DNA cargo, which leads to poor transfection efficiency. To overcome the lack of a reliable approach f

Several novel classes of molecular glasses were synthesized as photoresist materials for next generation lithography. These compounds were protected by protecting groups for chemically amplified systems and proved to possess high glass transition temperature (Tg) as well as amorphous properties. A positive-tone photoresist system with hexa(t-butoxy- carbonyloxyphenyl)benzene was demonstrated using E-beam lithography and 200 nm pattern size was obtained.

Cell-penetrating peptides (CPPs) have been widely utilized as efficient molecular tools for the delivery of bioactive cargoes such as peptides, proteins, and genetic material. However, to improve their versatility as tools in biological environments, the resistance of CPPs to enzymatic degradation and their structural stability must be improved to achieve long-term efficacy. Here we designed and synthesized novel artificial CPPs, poly(LysAibXaa), containing periodic α-aminoisobutyric acid (Aib)

Spider dragline silks have attracted intensive attention as eco-friendly tough materials because of their excellent mechanical property and biomass-based origin. Composite films based on a recombinant spider dragline silk protein (ADF3) from Araneus diadematus were prepared by doping with linear or telechelic poly(L-alanine) (L- or T-polyA, respectively) as a reinforcing agent. Higher tensile strength and toughness of the composite films were achieved with the addition of polyA compared with the

In order to construct unique polypeptide architectures, a novel telechelic-type initiator with two leucine ethyl ester units is designed for chemoenzymatic polymerization. Glycine or alanine ethyl ester is chemoenzymatically polymerized using papain in the presence of the initiator, and the propagation occurs at each leucine ethyl ester unit to produce the telechelic polypeptide. The formation of the telechelic polypeptides is confirmed by (1) H NMR and MALDI-TOF mass spectroscopies. It is revea

Elastin-like polypeptides containing proline were synthesized <italic>via</italic> chemoenzymatic polymerization and exhibited a temperature-dependent structural transition.