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51.
52.
Shoko Shinya Takayuki Ohnuma Reina Yamashiro Hisashi Kimoto Hideo Kusaoke Padmanabhan Anbazhagan André H. Juffer Tamo Fukamizo 《The Journal of biological chemistry》2013,288(42):30042-30053
Two carbohydrate binding modules (DD1 and DD2) belonging to CBM32 are located at the C terminus of a chitosanase from Paenibacillus sp. IK-5. We produced three proteins, DD1, DD2, and tandem DD1/DD2 (DD1+DD2), and characterized their binding ability. Transition temperature of thermal unfolding (Tm) of each protein was elevated by the addition of cello-, laminari-, chitin-, or chitosan-hexamer (GlcN)6. The Tm elevation (ΔTm) in DD1 was the highest (10.3 °C) upon the addition of (GlcN)6 and was markedly higher than that in DD2 (1.0 °C). A synergistic effect was observed (ΔTm = 13.6 °C), when (GlcN)6 was added to DD1+DD2. From isothermal titration calorimetry experiments, affinities to DD1 were not clearly dependent upon chain length of (GlcN)n; ΔGr° values were −7.8 (n = 6), −7.6 (n = 5), −7.6 (n = 4), −7.6 (n = 3), and −7.1 (n = 2) kcal/mol, and the value was not obtained for GlcN due to the lowest affinity. DD2 bound (GlcN)n with the lower affinities (ΔGr° = −5.0 (n = 3) ∼ −5.2 (n = 6) kcal/mol). Isothermal titration calorimetry profiles obtained for DD1+DD2 exhibited a better fit when the two-site model was used for analysis and provided greater affinities to (GlcN)6 for individual DD1 and DD2 sites (ΔGr° = −8.6 and −6.4 kcal/mol, respectively). From NMR titration experiments, (GlcN)n (n = 2∼6) were found to bind to loops extruded from the core β-sandwich of individual DD1 and DD2, and the interaction sites were similar to each other. Taken together, DD1+DD2 is specific to chitosan, and individual modules synergistically interact with at least two GlcN units, facilitating chitosan hydrolysis. 相似文献
53.
Rintaro Moroi Katsuya Endo Yoshitaka Kinouchi Hisashi Shiga Yoichi Kakuta Masatake Kuroha Yoshitake Kanazawa Yosuke Shimodaira Takahiko Horiuchi Seiichi Takahashi Tooru Shimosegawa 《Immunogenetics》2013,65(4):265-271
An association between FCGR3A-158 V/F polymorphism and biological responses to infliximab has been reported in Crohn’s disease (CD) in Western countries. However, little is known about the mechanism by which gene polymorphism affects the responses to infliximab. The aims of this study were to confirm the association in Japanese CD patients and to reveal the effect of gene polymorphism on biological responses to infliximab. Japanese CD patients were examined retrospectively at weeks 8 and 30. Clinical and biological responses were assessed by the Crohn’s disease activity index and C-reactive protein levels, respectively. The infliximab-binding affinity of natural killer (NK) cells from FCGR3A-158 V/V, V/F and F/F donors was examined. Infliximab-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) activities were also determined using transmembrane TNF-α-expressing Jurkat T cells as target cells and peripheral blood mononuclear cells (PBMCs) from V/V, V/F and F/F donors as effector cells. Biological responses at week 8 were statistically higher in V/V patients, whereas no significant differences were observed in either clinical responses at weeks 8 and 30 or biological responses at week 30 among the three genotypes. NK cells and PBMCs from V/V patients also showed higher infliximab-binding affinity and infliximab-mediated ADCC activity, respectively. Our results suggest that FCGR3A-158 polymorphism is a predicting factor of biological responses to infliximab in the early phases. FCGR3A-158 polymorphism was also found to affect the infliximab-binding affinity of NK cells and infliximab-mediated ADCC activity in vitro, suggesting that an effect on ADCC activity influences biological responses to infliximab in CD patients. 相似文献
54.
Kazuto Ishikawa Takashi Ohmori Hirokuni Miyamoto Toshiyuki Ito Yoshifumi Kumagai Masatoshi Sonoda Jirou Matsumoto Hisashi Miyamoto Hiroaki Kodama 《Applied microbiology and biotechnology》2013,97(3):1349-1359
NO 3 ? is a major nitrogen source for plant nutrition, and plant cells store NO 3 ? in their vacuoles. Here, we report that a unique compost made from marine animal resources by thermophiles represses NO 3 ? accumulation in plants. A decrease in the leaf NO 3 ? content occurred in parallel with a decrease in the soil NO 3 ? level, and the degree of the soil NO 3 ? decrease was proportional to the compost concentration in the soil. The compost-induced reduction of the soil NO 3 ? level was blocked by incubation with chloramphenicol, indicating that the soil NO 3 ? was reduced by chloramphenicol-sensitive microbes. The compost-induced denitrification activity was assessed by the acetylene block method. To eliminate denitrification by the soil bacterial habitants, soil was sterilized with γ irradiation and then compost was amended. After the 24-h incubation, the N2O level in the compost soil with presence of acetylene was approximately fourfold higher than that in the compost soil with absence of acetylene. These results indicate that the low NO 3 ? levels that are often found in the leaves of organic vegetables can be explained by compost-mediated denitrification in the soil. 相似文献
55.
Hisashi Hoshida Tsuneyasu Fujita Kamonchai Cha-aim Rinji Akada 《Applied microbiology and biotechnology》2013,97(12):5473-5482
Expression of foreign enzymes in yeast is a traditional genetic engineering approach; however, useful secretory enzymes are not produced in every case. The hyperthermostable α-amylase encoded by the AmyL gene of Bacillus licheniformis was expressed in Saccharomyces cerevisiae; however, it was only weakly produced and was degraded by the proteasome. To determine the cause of low α-amylase production, AmyL was expressed in a panel of yeast mutants harboring knockouts in non-essential genes. Elevated AmyL production was observed in 44 mutants. The knockout genes were classified into six functional categories. Remarkably, all non-essential genes required for N-linked oligosaccharide synthesis and a gene encoding an oligosaccharyl transferase subunit were identified. Immunoblotting demonstrated that differently underglycosylated forms of AmyL were secreted from oligosaccharide synthesis-deficient mutants, while a fully glycosylated form was produced by wild-type yeast, suggesting that N-linked glycosylation of AmyL inhibited its secretion in yeast. Mutational analysis of six potential N-glycosylation sites in AmyL revealed that the N33Q and N309Q mutations remarkably affected AmyL production. To achieve higher AmyL production in yeast, all six N-glycosylation sites of AmyL were mutated. In wild-type yeast, production of the resulting non-glycosylated form of AmyL was threefold higher than that of the glycosylated form. 相似文献
56.
Mao Horio Tamaki Ishima Yuko Fujita Ran Inoue Hisashi Mori Kenji Hashimoto 《Neurochemistry international》2013
d-Serine, an endogenous co-agonist of the N-methyl-d-aspartate (NMDA) receptor is synthesized from l-serine by serine racemase (SRR). A previous study of Srr knockout (Srr-KO) mice showed that levels of d-serine in forebrain regions, such as frontal cortex, hippocampus, and striatum, but not cerebellum, of mutant mice are significantly lower than those of wild-type (WT) mice, suggesting that SRR is responsible for d-serine production in the forebrain. In this study, we attempted to determine whether SRR affects the level of other amino acids in brain tissue. We found that tissue levels of d-aspartic acid in the forebrains (frontal cortex, hippocampus and striatum) of Srr-KO mice were significantly lower than in WT mice, whereas levels of d-aspartic acid in the cerebellum were not altered. Levels of d-alanine, l-alanine, l-aspartic acid, taurine, asparagine, arginine, threonine, γ-amino butyric acid (GABA) and methionine, remained the same in frontal cortex, hippocampus, striatum and cerebellum of WT and mutant mice. Furthermore, no differences in d-aspartate oxidase (DDO) activity were detected in the forebrains of WT and Srr-KO mice. These results suggest that SRR and/or d-serine may be involved in the production of d-aspartic acid in mouse forebrains, although further detailed studies will be necessary to confirm this finding. 相似文献
57.
58.
Tomokazu Ito Jumpei Iimori Sayuri Takayama Akihito Moriyama Ayako Yamauchi Hisashi Hemmi Tohru Yoshimura 《Journal of bacteriology》2013,195(24):5439-5449
Escherichia coli YggS is a member of the highly conserved uncharacterized protein family that binds pyridoxal 5′-phosphate (PLP). To assist with the functional assignment of the YggS family, in vivo and in vitro analyses were performed using a yggS-deficient E. coli strain (ΔyggS) and a purified form of YggS, respectively. In the stationary phase, the ΔyggS strain exhibited a completely different intracellular pool of amino acids and produced a significant amount of l-Val in the culture medium. The log-phase ΔyggS strain accumulated 2-ketobutyrate, its aminated compound 2-aminobutyrate, and, to a lesser extent, l-Val. It also exhibited a 1.3- to 2.6-fold increase in the levels of Ile and Val metabolic enzymes. The fact that similar phenotypes were induced in wild-type E. coli by the exogenous addition of 2-ketobutyrate and 2-aminobutyrate indicates that the 2 compounds contribute to the ΔyggS phenotypes. We showed that the initial cause of the keto acid imbalance was the reduced availability of coenzyme A (CoA); supplementation with pantothenate, which is a CoA precursor, fully reversed phenotypes conferred by the yggS mutation. The plasmid-borne expression of YggS and orthologs from Bacillus subtilis, Saccharomyces cerevisiae, and humans fully rescued the ΔyggS phenotypes. Expression of a mutant YggS lacking PLP-binding ability, however, did not reverse the ΔyggS phenotypes. These results demonstrate for the first time that YggS controls Ile and Val metabolism by modulating 2-ketobutyrate and CoA availability. Its function depends on PLP, and it is highly conserved in a wide range species, from bacteria to humans. 相似文献
59.
Yasuji Minoda Hisashi Yamagata Tohru Kodama 《Bioscience, biotechnology, and biochemistry》2013,77(7):1829-1830
Strains producing higher levels of cellulolytic enzymes were selected from among 520 strains of plant pathogenic fungi, Fusarium species, and F. oxysporum strain SUF850 was found to be the best producer. When strain SUF850 was cultured using one of three polysaccharides, Avicel, carboxy- methyl cellulose (CMC) or xylan, as a carbon source, the culture filtrate contained degrading activi- ties toward all three substrates, i.e., irrespective of the carbon source used. From the culture filtrate of Avicel-grown cells, four distinct enzymes were purified to homogeneity, as judged on SDS-PAGE. They were designated as CMCase I, CMCase II, /Miitrophenyl-β-d-cellobiosidase and xylanase, and the characteristics of the individual enzymes were examined and compared. 相似文献
60.
Shohei Sakuda Akira Isogai Tsukasa Makita Shogo Matsumoto Koshi Koseki Hisashi Kodama 《Bioscience, biotechnology, and biochemistry》2013,77(12):3251-3259
The structures of allosamidin (1) and methylallosamidin (2), novel insect chitinase inhibitors, were elucidated as 1 and 2 by acid hydrolysis experiments and analyses of 2d-NMR spectra. They are unique basic pseudotrisaccharides consisting of 2-acetamido-2-deoxy-d-allose (N-acetyl-d- allosamine) and a novel aminocyclitol derivative (3), termed allosamizoline. 相似文献