A5012013197- Viral gastroenteritis research and epidemiology
- Virus-based gene therapy research
- Viral Infections and Immunology Research
- Bacterial Genetics and Biotechnology
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- DNA and Nucleic Acid Chemistry
- Drug Transport and Resistance Mechanisms
- Animal Virus Infections Studies
- Bacteriophages and microbial interactions
- Advanced biosensing and bioanalysis techniques
- Respiratory viral infections research
- Monoclonal and Polyclonal Antibodies Research
- Adenosine and Purinergic Signaling
- Antibiotic Resistance in Bacteria
- Whipple's Disease and Interleukins
- Amino Acid Enzymes and Metabolism
- Viral Infections and Vectors
- Advanced Thermodynamic Systems and Engines
- Neuroendocrine Tumor Research Advances
- RNA and protein synthesis mechanisms
- Vector-Borne Animal Diseases
- Diagnosis and Treatment of Venous Diseases
- Muscle and Compartmental Disorders
- Antibiotics Pharmacokinetics and Efficacy
National Institute of Infectious Diseases
2005-2025
National Institutes of Health
2000-2014
Rakuno Gakuen University
2009
Osaka University
1996-2000
Chiba University
1992-1995
Kyoto University
1994
The region including the conserved Ser65-Asp66 dipeptide in tetracycline/H+ antiporter (TET) encoded by transposon Tn10 is thought to play a gating role (Yamaguchi, A., Ono, N., Akasaka, T., Noumi, and Sawai, T. (1990) J. Biol. Chem. 265, 15525-15530). putative interhelix loop2-3, which also includes sequence motif, GXXXXRXGRR, found all TET proteins sugar/H+ symporters. Through combination of localized random site-directed mutagenesis, each residue loop2-3 was replaced. Among 10 residues...
Noroviruses (NoVs) bind to histo-blood group antigens, namely, ABH antigens and Lewis antigens. We previously showed the NoVs GI/2, GI/3, GI/4, GI/8 were able strongly a (Le(a)) antigen, which is expressed by individuals who are nonsecretors. In this study, investigate how interact with GI NoV virion protein 1 (VP1), we determined crystal structures of P domain VP1 from Funabashi 258 (FUV258) strain (GI/2) in complexes Le(a), Le(b), H type 1, or A The compared those NV/68 (GI/1), does not...
Three conserved aspartyl residues located in the putative transmembrane helices Tn10-encoded metal-tetracycline/H+ antiporter were replaced by Asn, Lys, or Glu with oligonucleotide-directed site-specific mutagenesis. Replacement of Asp84 Asp15 Asn Lys caused a severe defect tetracycline transport activity, however, Glu84 and Glu15 mutants retained 150 40% wild type respectively, indicating critical role negative charge. The increase activity mutant was due to an affinity for substrate....
ABSTRACT Norovirus 3C-like proteases are crucial to proteolytic processing of norovirus polyproteins. We determined the crystal structure protease from Chiba virus, a norovirus, at 2.8-Å resolution. An active site including Cys139 and His30 is present, as hydrogen bond network that stabilizes conformation. In oxyanion hole backbone, structural difference was observed probably upon substrate binding. A peptide substrate/enzyme model shows several interactions between two components critical...
A novel tetracycline derivative, DMG-DMDOT [9-(N,N-dimethylglycylamido)-6-demethyl-6-deoxytetracycline] , is one of the glycylcyclines which have a broad antibacterial spectrum, including many tetracyclineresistant bacteria (R.T. Testa, P.J. Petersen, N.V. Jacobus, P.-E. Sum, V.J. Lee, and F.P. Tally, Antimicrob. Agents Chemother. 37:2270-2277, 1993). The mechanism by overcomes efflux-based resistance was investigated. Tetracycline-resistant Escherichia coli cells carrying an R plasmid...
ABSTRACT Human sapovirus (HuSaV), first identified in the 1970s, is a significant cause of acute gastroenteritis, particularly young children. Despite its clinical significance, research on HuSaV has been limited due to absence reliable cell culture system. In 2020, breakthrough study reported that GI.1 and GII.3 strains could be cultured serially propagated using HuTu80 cells presence bile acids. However, 2024, subsequent effective replication requires specialized have undergone over 100...
ABSTRACT The 3C-like protease of the Chiba virus, a Norwalk-like is one chymotrypsin-like proteases. To identify active-site amino acid residues in this protease, 37 charged and putative nucleophile, Cys139, within GDCG sequence were individually replaced with Ala 3BC precursor, followed by expression Escherichia coli , where active would cleave into 3B (VPg) 3C (protease). Among 38 mutants, 7 mutants (R8A, H30A, K88A, R89A, D138A, C139A, H157A) completely or nearly lost proteolytic...
The properties of site-directed mutants as to the putative hydrophilic loop region between hydrophobic segments 2 and 3 in transposon TnlO-encoded metal-tetracycline/H+ antiporter (TET) were reported our previous paper (Yamaguchi, A., Someya, Y., Sawai, T. (1992) J. Biol.Chem.267,[19155][19156][19157][19158][19159][19160][19161][19162].The 8 9 contains a conserved sequence motif, GXXXXKXGEK, which is derivative GXXXXRXGRR, loop,-^.Site-directed mutagenesis studies on loop, revealed that two...
Following the declaration of wild-type 2 poliovirus eradication in 2015, type component was removed from live-attenuated oral polio vaccine (OPV). This change implies a need to improve global coverage through routine immunization with inactivated (IPV), ensure immunity. Several manufacturers use Sabin OPV strains for IPV production (sIPV), rather than usual used conventional (cIPV). However, contrast cIPV, potency assays sIPV have not been standardized, no international references exist, and...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSite-Specificity of the Second-Site Suppressor Mutation Asp-285 .fwdarw. Asn Mutant Metal-Tetracycline/H+ Antiporter Escherichia coli and Effects Amino Acid Substitutions at First Second SitesYuichi Someya, Akiko Niwa, Tetsuo Sawai, Akihito YamaguchiCite this: Biochemistry 1995, 34, 1, 7–12Publication Date (Print):January 10, 1995Publication History Published online1 May 2002Published inissue 10 January 1995https://doi.org/10.1021/bi00001a002RIGHTS...
At necropsy, an 11-year-old Japanese Black cow with anemia, leukocytopenia, and progressive hind limb ataxia had marked diffuse splenomegaly multiple masses in the thoracic vertebrae. Histologically, neoplastic erythrophagocytic histiocytes were splenic red pulp, vertebral masses, blood vessels of liver lungs. The spinal cord was compressed by masses. Clinicopathological, macroscopic, histologic findings consistent hemophagocytic histiocytic sarcoma. Vertebral involvement compression...
Abstract In order to identify the repertoire of antibodies generated on natural infection norovirus (NoV) in humans, and characterize human monoclonal against NoV, three phage‐displayed antibody libraries originating from healthy person(s) were screened using purified virus‐like particles (VLPs) strain Narita 104 (r104, genogroup II, genotype 4) or Chiba 407 (rCV, I, as antigens. On screening with r104, 62 clones isolated. Among these antibodies, two clones, 12A11 12B10, showed...
A carboxyl group of Asp-285 is essential for tetracycline/H+ antiport mediated by the transposon Tn10-encoded metal-tetracycline/H+ antiporter (TetA) Escherichia coli (Yamaguchi, A., Akasaka, T., Ono, N., Someya, Y., Nakatani, M., and Sawai, T. (1992) J. Biol. Chem. 267, 7490-7498). Spontaneous tetracycline resistance revertants were isolated from E. cells carrying Asn-285 mutant tetA gene. All due to second-site mutation at codon 220 GCG (Ala) GAG (Glu). The Km value transport revertant...
The norovirus 3C-like protease is a member of the chymotrypsin-like serine superfamily. Previous characterization its crystal structure has implicated Glu54–His30–Cys139 triad in catalysis. In present study, Glu54 residue was subjected to site-saturation mutagenesis, with result that nearly half mutants retained significant proteolytic activity. It suggested carboxylate at position 54 not essential for vitro assays proteolysis revealed most relatively high When mutation combined Ser Cys139...
The Glu54 residue of the norovirus 3C-like protease was implicated in proteolysis as a third-member carboxylate catalytic triad. E54L mutant cleaved sequence (133)LSFE/AP between 3B and 3C regions polyprotein, but did not cleave (198)ATSE/GK 3A 3B. 3BC junction mutation (3B-L133A or 3B-F135S) hampered cleavage by protease, whereas 3AB (3A-A198L, S200F) allowed to digest. These results indicate that is substrate-specificity requires large hydrophobic amino acid residues at both P4 P2...
Infection of insect cells with recombinant baculoviruses carrying the VP1 gene from Chiba strain norovirus resulted in production 57 and 50 kDa proteins, assembly a smaller, 23 nm form virus-like particles (VLPs), together normal, 38 VLPs. The N-terminal residues proteins were Ala4 Thr45, respectively. When tripeptide Leu43-Ala44-Thr45 was changed to Ala-Pro-Val, only VLPs assembled. showed essentially same pattern carbohydrate binding as VLPs, despite significant difference degree Lewis b...
Noroviruses are major causative agents of acute nonbacterial gastroenteritis in humans. There neither antiviral therapeutic nor vaccines for noroviruses at this time. To evaluate the potential usefulness two previously isolated human monoclonal antibody fragments, CV-1A1 and CV-2F5, we first conducted a single-particle analysis to determine cryo-electron microscopy structure virus-like particles (VLPs) from genogroup I genotype 4 (GI.4) Chiba strain uniformly coated with fragments. The...