Publications by authors named "Hikaru Seki"

Pseudomonas aeruginosa is an opportunistic pathogen, commonly associated with human airway infections. Based on its amino acid sequence similarity with Pyrococcus furiosusprotease I, P. aeruginosa PfpI was originally annotated as an intracellular protease.

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Unable to move on their own, plants have acquired the ability to produce a wide variety of low molecular weight compounds to survive against various stresses. It is estimated that there are as many as one million different kinds. Plants also have the ability to accumulate high levels of proteins.

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Glycyrrhizin, a type of the triterpenoid saponin, is a major active ingredient contained in the roots of the medicinal plant licorice (Glycyrrhiza uralensis, G. glabra and G. inflata), and is used worldwide in diverse applications, such as herbal medicines and sweeteners.

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CRISPR-Cas9-mediated disruption of a licorice cellulose synthase-derived glycosyltransferase gene, GuCSyGT, demonstrated the in planta role of GuCSyGT as the enzyme catalyzing 3-O-glucuronosylation of triterpenoid aglycones in soyasaponin biosynthesis. Triterpenoid glycosides (saponins) are a large, structurally diverse group of specialized metabolites in plants, including the sweet saponin glycyrrhizin produced by licorice (Glycyrrhiza uralensis) and soyasaponins that occur widely in legumes, with various bioactivities. The triterpenoid saponin biosynthetic pathway involves the glycosylation of triterpenoid sapogenins (the non-sugar part of triterpenoid saponins) by glycosyltransferases (GTs), leading to diverse saponin structures.

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Herein we introduce 3-vinyl-1,2,4-triazines derivatives as dual-reactive linkers that exhibit selectivity towards cysteine and specific strained alkynes, enabling conjugate addition and inverse electron-demand Diels-Alder (IEDDA) reactions. This approach facilitates site-selective bioconjugation of biologically relevant peptides, followed by rapid and highly selective reactions with bicyclononyne (BCN) reagents.

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Cytochrome P450 monooxygenases (CYPs) are enzymes that play critical roles in the structural diversification of triterpenoids. To perform site-specific oxidations of the triterpene scaffold, CYPs require electrons transferred by NADPH-cytochrome P450 reductase (CPR), which is classified into two main classes, class I and class II, based on their structural difference. is a triterpenoids-producing model legume with one CPR class I gene () and a minimum of two CPR class II genes ( and ).

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Soybeans (Glycine max) develop newly differentiated aerenchymatous phellem (AP) in response to waterlogging stress. AP is formed in the hypocotyl and root, thus contributing to internal aeration and adaptation to waterlogging for several legumes. Extensive accumulation of triterpenoids - lupeol and betulinic acid - has been identified in AP.

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A high-quality genome assembly is imperative to explore the evolutionary basis of characteristic attributes that define chemotype and provide essential resources for a molecular breeding strategy for enhanced production of medicinal metabolites. Here, using single-molecule high-fidelity (HiFi) sequencing reads, we report chromosome-scale genome assembly for Chinese licorice (Glycyrrhiza uralensis), a widely used herbal and natural medicine. The entire genome assembly was achieved in eight chromosomes, with contig and scaffold N50 as 36.

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Oleanolic acid is a pentacyclic triterpenoid found in numerous plant species and is a precursor to several bioactive triterpenoids with commercial potential. However, oleanolic acid accumulates at low levels in plants, and its chemical synthesis is challenging. Here, we established a method for producing oleanolic acid in substantial quantities heterologous expression of pathway enzymes in .

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Triterpenoids constitute a group of specialized plant metabolites with wide structural diversity and high therapeutic value for human health. Cytochrome P450 monooxygenases (CYP) are a family of enzymes important for generating the structural diversity of triterpenoids by catalyzing the site-specific oxidization of the triterpene backbone. The CYP716 enzyme family has been isolated from various plant families as triterpenoid oxidases; however, their experimental crystal structures are not yet available and the detailed catalytic mechanism remains elusive.

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Triterpenoids are plant specialized metabolites with various pharmacological activities. They are widely distributed in higher plants, such as legumes. Because of their low accumulation in plants, there is a need for improving triterpenoid production.

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Uridine 5'-diphosphate (UDP)-glucose dehydrogenase (UGD) produces UDP-glucuronic acid from UDP-glucose as a precursor of plant cell wall polysaccharides. UDP-glucuronic acid is also a sugar donor for the glycosylation of various plant specialized metabolites. Nevertheless, the roles of UGDs in plant specialized metabolism remain poorly understood.

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We herein report experimental applications of a novel, automated computational approach to chemical reaction network (CRN) identification. This report shows the first chemical applications of an autonomous tool to identify the kinetic model and parameters of a process, when considering both catalytic species and various integer and non-integer orders in the model's rate laws. This kinetic analysis methodology requires only the input of the species within the chemical system (starting materials, intermediates, products, ) and corresponding time-series concentration data to determine the kinetic information of the chemistry of interest.

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Methods for residue-selective and stable modification of canonical amino acids enable the installation of distinct functionality which can aid in the interrogation of biological processes or the generation of new therapeutic modalities. Herein, we report an extensive investigation of reactivity and stability profiles for a series of vinylheteroarene motifs. Studies on small molecule and protein substrates identified an optimum vinylheteroarene scaffold for selective cysteine modification.

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Background: Fabaceae plants appear to contain larger numbers of subclade IVa basic-helix-loop-helix (bHLH) transcription factors than other plant families, and some members of this subclade have been identified as saponin biosynthesis regulators. We aimed to systematically elucidate the diversification of this subclade and obtain insights into the evolutionary history of saponin biosynthesis regulation in Fabaceae.

Results: In this study, we collected sequences of subclade IVa bHLH proteins from 40 species, including fabids and other plants, and found greater numbers of subclade IVa bHLHs in Fabaceae.

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Licorice (Glycyrrhiza) produces glycyrrhizin, a valuable triterpenoid saponin, which exhibits persistent sweetness and broad pharmacological activities. In the genus Glycyrrhiza, three species, Glycyrrhiza uralensis, Glycyrrhiza glabra and Glycyrrhiza inflata, produce glycyrrhizin as their main triterpenoid saponin, which has a ketone group at C-11. Other Glycyrrhiza species produce mainly oleanane-type saponins, which harbor homoannular or heteroannular diene structures that lack the C-11 ketone.

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Antibody-drug conjugates (ADCs) harness the highly specific targeting capabilities of an antibody to deliver a cytotoxic payload to specific cell types. They have garnered widespread interest in drug discovery, particularly in oncology, as discrimination between healthy and malignant tissues or cells can be achieved. Nine ADCs have received approval from the US Food and Drug Administration and more than 80 others are currently undergoing clinical investigations for a range of solid tumours and haematological malignancies.

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Triterpenoid saponins are specialised metabolites distributed widely in the plant kingdom that consist of one or more sugar moieties attached to triterpenoid aglycones. Despite the widely accepted view that glycosylation is catalysed by UDP-dependent glycosyltransferase (UGT), the UGT which catalyses the transfer of the conserved glucuronic acid moiety at the C-3 position of glycyrrhizin and various soyasaponins has not been determined. Here, we report that a cellulose synthase superfamily-derived glycosyltransferase (CSyGT) catalyses 3-O-glucuronosylation of triterpenoid aglycones.

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Site-selective modification of peptides and proteins has resulted in the development of a host of novel tools for the study of cellular systems or the synthesis of enhanced biotherapeutics. There is a need for useful methodologies that enable site-selective modification of native peptides or proteins, which is even more prevalent when modification of the biomolecule with multiple payloads is desired. Herein, we report the development of a novel dual functional divinylpyrimidine (dfDVP) platform that enables robust and modular modification of peptides, antibody fragments and antibodies.

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Morolic acid is a plant-derived triterpenoid that possesses pharmacological properties such as cytotoxicity, as well as anti-HIV, anti-HSV, anti-inflammatory, and antidiabetic effects. The significant therapeutic properties of morolic acid are desirable in the context of pharmacological and drug development research, but the low accessibility of morolic acid from natural resources limits its applications. In the present study, we developed a microbial system for the production of morolic acid.

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Grey mangrove () is a traditional medicine used for the treatment of various diseases, including rheumatism and ulcers; however, the compounds responsible for its curative effects remain largely unknown. Triterpenoids are a diverse group of plant-specialized metabolites derived from a common precursor, 2,3-oxidosqualene. Triterpenoids are potentially responsible for the beneficial effects of ; however, the chemical profiles of triterpenoids in and their biosynthetic genes have not been identified.

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The triterpenes are structurally diverse group of specialized metabolites with important roles in plant defense and human health. Glycyrrhizin, with a carboxyl group at C-30 of its aglycone moiety, is a valuable triterpene glycoside, the production of which is restricted to legume medicinal plants belonging to the species. Cytochrome P450 monooxygenases (P450s) are important for generating triterpene chemodiversity by catalyzing site-specific oxidation of the triterpene scaffold.

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Plants produce various prenylated phenolic metabolites, including flavonoids, phloroglucinols, and coumarins, many of which have multiple prenyl moieties and display various biological activities. Prenylated phenylpropanes, such as artepillin C (3,5-diprenyl--coumaric acid), exhibit a broad range of pharmaceutical effects. To date, however, no prenyltransferases (PTs) involved in the biosynthesis of phenylpropanes and no plant enzymes that introduce multiple prenyl residues to native substrates with different regio-specificities have been identified.

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Lotus japonicus is an important model legume plant in several fields of research, such as secondary (specialized) metabolism and symbiotic nodulation. This plant accumulates triterpenoids; however, less information regarding its composition, content and biosynthesis is available compared with Medicago truncatula and Glycine max. In this study, we analyzed the triterpenoid content and composition of L.

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Triterpenoids are widely distributed among plants of the legume family. However, most studies have focused on triterpenoids and their biosynthetic enzymes in model legumes. We evaluated the triterpenoid aglycones profile of the medicinal legume tree Bauhinia forficata by gas chromatography-mass spectrometry.

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