Publications by authors named "Toshihiro Kuroita"

Background: Rapid and accurate diagnosis of individuals with SARS-CoV-2 infection is an effective way to prevent and control the spread of COVID-19. Although the detection of SARS-CoV-2 viral RNA by RT-qPCR is the gold standard for COVID-19 testing, the use of antigen-detecting rapid diagnostic tests (Ag-RDTs) is emerging as a complementary surveillance tool as Omicron case numbers skyrocket worldwide. However, the results from Ag-RDTs are less accurate in individuals with low viral loads.

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Recombinant protein technology is an important tool in many industrial and pharmacological applications. Although the success rate of obtaining soluble proteins is relatively low, knowledge of protein expression/solubility under 'standard' conditions may increase the efficiency and reduce the cost of proteomics studies. In this study, we conducted a genome-scale experiment to assess the overexpression and the solubility of human full-length cDNA in an in vivo Escherichia coli expression system and a wheat germ cell-free expression system.

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Appropriate resources and expression technology necessary for human proteomics on a whole-proteome scale are being developed. We prepared a foundation for simple and efficient production of human proteins using the versatile Gateway vector system. We generated 33,275 human Gateway entry clones for protein synthesis, developed mRNA expression protocols for them and improved the wheat germ cell-free protein synthesis system.

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We have isolated and characterized a gene for a putative protein-disulfide oxidoreductase (phdsb) in the archaeon Pyrococcus horikoshii. The open reading frame of phdsb encodes a protein of 170 amino acids with an NH(2)-terminal extension similar to the bacterial signal peptides. The putative mature region of PhDsb includes a sequence motif, Cys-Pro-His-Cys (CPHC), that is conserved in members of the bacterial DsbA family, but otherwise the archaeal and bacterial sequences do not show substantial similarity.

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Cypoviruses are insect viruses that produce a cytoplasmic crystalline particle called the polyhedron in which progeny virions are occluded. The virion structural protein, VP3, is implicated in the occlusion of viral particles into polyhedra. In this study, we determined the amino acid sequence of VP3 required for occlusion of viral particles into polyhedra and proposed that this sequence could be used as an immobilization signal to direct the stable incorporation of foreign proteins into polyhedra.

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To search for restriction endonucleases, we used a novel plant-based cell-free translation procedure that bypasses the toxicity of these enzymes. To identify candidate genes, the related genomes of the hyperthermophilic archaea Pyrococcus abyssi and Pyrococcus horikoshii were compared. In line with the selfish mobile gene hypothesis for restriction-modification systems, apparent genome rearrangement around putative restriction genes served as a selecting criterion.

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Article Synopsis
  • A study explored a method to control the proofreading and polymerase activities of archaeal DNA polymerases, focusing on the family B DNA polymerase from Thermococcus kodakaraensis KOD1.
  • Mutating a "unique loop" in the exonuclease domain resulted in significant changes in 3'-5' exonuclease activity among various H147 mutants, ranging from 9% to 276% compared to the wild-type enzyme.
  • The crystal structure analysis of the H147E mutant revealed it maintains good PCR performance and fidelity, indicating that interactions between the unique loop and Thumb domain play a crucial role in shaping the enzyme's properties.
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Specific interactions between transcription factors and cis-acting DNA sequence motifs are primary events for the transcriptional regulation. Many regulatory elements appear to diverge from the most optimal recognition sequences. To evaluate affinities of a transcription factor to various suboptimal sequences, we have developed a new detection method based on the surface plasmon resonance (SPR) imaging technique.

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Penicillin binding proteins (PBPs) are penicillin-sensitive DD-peptidases catalyzing the terminal stages of bacterial cell wall assembly. We identified a Dictyostelium discoideum gene that encodes a protein of 522 amino acids showing similarity to Escherichia coli PBP4. The D.

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In situ hybridization is one of the most important techniques to visualize gene expression at the cellular level in various tissues. The in situ hybridization-AT tailing (ISH-AT) method uses a specially designed and synthesized oligonucleotide probe that has (AT)10 on the 3' side. This (AT)10 of the probe is elongated by DeltaTth DNA polymerase in the presence of dATP, dTTP, and labeled dUTP in the tissue after hybridization.

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A high-throughput cell-free protein synthesis method has been described. The methodology is based on a bilayer diffusion system that enables the continuous supply of substrates, together with the continuous removal of small byproducts, through a phase between the translation mixture and substrate mixture. With the use of a multititer plate the system was functional for a prolonged time, and as a consequence yielded more than 10 times that of the similar batch-mode reaction.

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