宇野 知秀 | ![]() |
ウノ トモヒデ | |
大学院農学研究科 生命機能科学専攻 | |
教授 | |
生物関係 |
研究論文(学術雑誌)
Rab proteins are small GTP-binding proteins and are the largest family in the Ras GTPase superfamily and mediate vesicular transport in cells. Diverse insulin-like peptides, such as bombyxin, are synthesized in the brain and secreted into the haemolymph by the corpus allatum (CA). In the brain of Bombyx mori, Rabs are expressed in a specific area; however, which Rabs actually link the secretion of bombyxin remains unknown. A double-staining analysis of nine Rabs ( Rab1, 3, 6, 7, 14, 21, 26, 39 and X4) and bombyxin indicated that Rab3-, Rab7-, Rab39-and RabX4-immunohistochemical reactivity (ir) areas overlapped with bombyxin-ir in the brain and CA in B. mori, while Rab6-, Rab14-and Rab21-irs partially overlapped in the CA. Rab1-ir occurred in the other immunopositive areas in CA. Rab26-ir did not occur in the brain. Rab39-ir occurred in UNC104, Rab39- effector,-immunopositive neurons in the brain and CA. Thus, Rab3, 7, 39 and X4 may regulate the exocytosis of bombyxin.
CZECH ACAD SCI, INST ENTOMOLOGY, 2021年, EUROPEAN JOURNAL OF ENTOMOLOGY, 118, 307 - 314, 英語研究論文(学術雑誌)
BACKGROUND: Anorexia is a serious problem in patients with gastric cancer who have undergone gastrectomy. Ghrelin, an orexigenic hormone primarily secreted from the stomach, has been proposed to prevent anorexia. Significant reduction in plasma ghrelin levels after gastrectomy may contribute to lack of appetite and weight loss. In this study, we investigated the effects of Z-505, a ghrelin receptor agonist, on anorexia after total gastrectomy (TG) in a rat model. METHODS AND MATERIALS: Male Sprague-Dawley rats were used to establish a TG model, and then sham-operated (control) and TG rats were randomly assigned to four subgroups receiving administration of Z-505 (100 mg/kg, p.o., once daily) or vehicle for 14 d from day 14 to day 27 after TG. The food intake, body weight, and fat weight were evaluated during the test period. Moreover, the neuronal activity in the hypothalamus was evaluated on day 21 to investigate the mechanism of action of Z-505. RESULTS: In TG rats, Z-505 significantly improved the decrease in cumulative food intake induced by the surgery over 14 d (TG + vehicle; 213.8 ± 15.3 g, n = 12 versus TG + Z-505; 258.2 ± 13.1 g, n = 14, P < 0.05). Z-505 also significantly increased fat weight and had a milder effect on body weight over 14 d. In addition, Z-505 significantly increased the number of c-Fos-positive cells in the hypothalamic arcuate nucleus (TG + vehicle; 17.8 ± 2.0, n = 12 versus TG + Z-505; 72.2 ± 11.8, n = 12, P < 0.001). CONCLUSIONS: Z-505 may be a useful therapeutic treatment for anorexia after TG.
2020年02月, The Journal of surgical research, 246, 527 - 534, 英語, 国際誌研究論文(学術雑誌)
We had previously reported a prostaglandin E synthase (bmPGES) in the silkworm Bombyx mori that catalyzes the isomerization of PGH2 to PGE2. The present study aimed to provide a genome-editing characterization of bmPGES in B. mori. Results showed bmPGES gene disruption to result in a reduced content of PGE2. The change affected the expression of chorion genes and egg formation in silkworms. Collectively, the results indicated that bmPGES could be involved in reproduction of B. mori. Therefore, this study provides insights into the physiological role of bmPGES and PGE2 in silkworms.
2020年01月08日, Biochemical and biophysical research communications, 521 (2), 347 - 352, 英語, 国際誌研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
The small Rab GTPases are key regulators of membrane vesicle trafficking. Ovaries of Periplaneta americana (Linnaeus) (Blattodea: Blattidae) have small molecular weight GTP/ATP-binding proteins during early and late vitellogenic periods of oogenesis. However, the identification and characterization of the detected proteins have not been yet reported. Herein, we cloned a cDNA en
2018年10月, Insect science, 25 (5), 751 - 764, 英語[査読有り]
研究論文(学術雑誌)
CYP2C9 is a human microsomal cytochrome P450c (CYP). Much variation in CYP2C9 levels and activity can be attributed to polymorphisms of this gene. Wild-type CYP2C9 and ten mutants were co-expressed with NADPH-cytochrome P450 reductase in Escherichia coli. The hydroxylase activities toward steroids were examined. CYP2C9.2, CYP2C9.3, CYP2C9.4, CYP2C9.16, CYP2C9.28, CYP2C9.48 and
2018年08月, Biopharmaceutics & Drug Disposition, 39 (8), 371 - 377, 英語[査読有り]
研究論文(学術雑誌)
The aromatic compound p-hydroxybenzoate (PHBA) is an important material with multiple applications, including as a building block of liquid crystal polymers in chemical industries. The cytochrome P450 (CYP) enzymes are beneficial monooxygenases for the synthesis of chemicals, and CYP53A15 from fungus Cochliobolus lunatus is capable of executing the hydroxylation from benzoate to PHBA. Here, we constructed a system for the bioconversion of benzoate to PHBA in Escherichia coli cells coexpressing CYP53A15 and human NADPH-P450 oxidoreductase (CPR) genes as a redox partner. For suitable coexpression of CYP53A15 and CPR, we originally constructed five plasmids in which we replaced the N-terminal transmembrane region of CYP53A15 with a portion of the N-terminus of various mammalian P450s. PHBA productivity was the greatest when CYP53A15 expression was induced at 20°C in 2×YT medium in host E. coli strain ΔgcvR transformed with an N-terminal transmembrane region of rabbit CYP2C3. By optimizing each reaction condition (reaction temperature, substrate concentration, reaction time, and E. coli cell concentration), we achieved 90% wholecell conversion of benzoate. Our data demonstrate that the described novel E. coli bioconversion system is a more efficient tool for PHBA production from benzoate than the previously described yeast system.
Korean Society for Microbiology and Biotechnology, 2018年03月01日, Journal of Microbiology and Biotechnology, 28 (3), 439 - 447, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
Rab proteins are small monomeric GTPases/GTP-binding proteins, which form the largest branch of the Ras superfamily. The different Rab GTPases are localized to the cytosolic face of specific intracellular membranes, where they function as regulators of distinct steps in membrane trafficking. RabX4 is an insect-specific Rab protein that has no close homolog in vertebrates. There is little information about insect-specific Rab proteins. RabX4 was expressed in Escherichia coli and subsequently purified. Antibodies against Bombyx mori RabX4 were produced in rabbits for western immunoblotting and immunohistochemistry. Western blotting of neural tissues revealed a single band, at approximately 26kD. RabX4-like immunohistochemical reactivity was restricted to neurons of the pars intercerebralis and dorsolateral protocerebrum in the brain. Further immunohistochemical analysis revealed that RabX4 colocalized with Rab6 and bombyxin in the corpus allatum, a neuronal organ that secretes neuropeptides synthesized in the brain into the hemolymph. RabX4 expression in the frontal ganglion, part of the insect stomatogastric nervous system that is found in most insect orders, was restricted to two neurons on the outer region and did not colocalize with allatotropin or Rab6. Furthermore, RNA interference of RabX4 decreased bombyxin expression levels in the brain. These findings suggest that RabX4 is involved in the neurosecretion of a secretory organ in Bombyx mori.
WILEY, 2017年09月, ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY, 96 (1), 英語[査読有り]
研究論文(学術雑誌)
Aspergillus oryzae is a fungus widely used in traditional Japanese fermentation industries. Cytochrome P450 (CYP) proteins are ubiquitously distributed in nature and display a broad range of enzymatic activities. A novel CYP52 (CYP52G3) gene was found in A. oryzae. In this study, we report the functional characterization of CYP52G3. The recombinant protein was expressed heterologously in Escherichia coli, and its membrane fraction isolated. CYP52G3 showed activities for 7-ethoxycoumarin and alpha-naphtoflavone. Furthermore, CYP52G3 hydroxylated flavanone at the 4' and 6 position and metabolized some hydroxyl-flavanones and steroids. Bioconversion experiments indicated that CYP52G3 could convert flavanone and testosterone in a synthetic medium. The conversion rates of flavanone and testosterone at 24 H were 50% and 70%, respectively. These results support that CYP52G3 could prove a useful enzyme for the efficient production of new compounds from flavonoids and steroids. (C) 2016 International Union of Biochemistry and Molecular Biology, Inc.
WILEY, 2017年05月, BIOTECHNOLOGY AND APPLIED BIOCHEMISTRY, 64 (3), 385 - 391, 英語[査読有り]
研究論文(学術雑誌)
The aldo-keto reductase AKR2E4 reduces 3-dehydroecdysone to ecdysone in the silkworm Bombyx mori L. In this study, a quantitative polymerase chain reaction analysis revealed that the level of AKR2E4 mRNA was higher in the testes than in other tissues, and a western immunoblot analysis revealed that the AKR2E4 content in the testes was stage-specific from the fifth larval instar to the pupal stage. Immunohistochemical analysis showed that the AKR2E4 protein was present in cyst cells associated with sperm cells and spermatocytes. These results indicate that AKR2E4 plays an important role in 3-dehydroecdysone conversion to ecdysone and spermatogenesis in silkworm testes.
Library of the University of Arizona, 2017年, Journal of Insect Science, 17 (5), 1 - 3, 英語[査読有り]
研究論文(学術雑誌)
In eukaryotic cells, Rab guanosine triphosphate-ases serve as key regulators of membrane-trafficking events, such as exocytosis and endocytosis. Rab3, Rab6, and Rab27 control the regulatory secretory pathway of neuropeptides and neurotransmitters. The cDNAs of Rab3, Rab6, and Rab27 from B. mori were inserted into a plasmid, transformed into Escherichia coli, and then subsequently purified. We then produced antibodies against Rab3, Rab6, and Rab27 of Bombyx mori in rabbits and rats for use in western immunoblotting and immunohistochemistry. Western immunoblotting of brain tissue revealed a single band at approximately 26 kDa. Immunohistochemistry results revealed that Rab3, Rab6, and Rab27 expression was restricted to neurons in the pars intercerebralis and dorsolateral protocerebrum of the brain. Rab3 and Rab6 co-localized with bombyxin, an insect neuropeptide. However, there was no Rab that co-localized with prothoracicotropic hormone. The corpus allatum secretes neuropeptides synthesized in the brain into the hemolymph. Results showed that Rab3 and Rab6 co-localized with bombyxin in the corpus allatum. These findings suggest that Rab3 and Rab6 are involved in neurosecretion in B. mori. This study is the first to report a possible relationship between Rab and neurosecretion in the insect corpus allatum.
SPRINGER, 2016年07月, HISTOCHEMISTRY AND CELL BIOLOGY, 146 (1), 59 - 69, 英語[査読有り]
研究論文(学術雑誌)
We evaluated the metabolism of several herbicides and progesterone by two P450 proteins (CYP1A9 and CYP1C1) from Japanese eel (Anguilla japonica). Expression vectors harboring CYP1A9 and CYP1C1 sequences were introduced into Escherichia coli. E. coli membrane fractions were incubated with each substrate, and the metabolites were analyzed. CYP1A9 and CYP1C1 deethylated 7-ethoxycoumarin and phenacetin, and demethylated chlorotoluron, diuron, and linuron. CYP1C1 specifically hydroxlyated progesterone at the 6 beta and 16 alpha positions. Five amino acids of CYP1A9 related to substrate binding were selected for mutation analyses [CYP1A9(F128A), CYP1A9(F229A), CYP1A9(F263A), CYP1A9(V387A), and CYP1A9(I391A)]. Two variants, CYP1A9(F229A) and CYP1A9(F128A), changed the ratio of 16a hydroxyprogesterone to 613 hydroxyprogesterone. Among all the variants, CYP1A9(F263A) showed the highest activity towards substrates used. CYP1A9(V387A) and CYP1A9(I391A) showed higher activities than that of CYP1A9 toward progesterone. The substrate specificity of CYP1A9 may be altered by replacing an amino acid related to substrate binding. (C) 2015 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2015年09月, ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY, 40 (2), 360 - 368, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
Rab guanosine triphosphatases in eukaryotic cells are key regulators of membrane-trafficking events, such as exocytosis and endocytosis. Rab7 regulates traffic from early to late endosomes and from late endosomes to vacuoles/lysosomes. The Rab7-interacting lysosomal protein (RILP) was extracted from the silkworm, Bombyx mori (B. mori), and expressed in Escherichia coli (E. coli), followed by its purification. The glutathione sulfotransferase pull-down assay revealed that Rab7 of B. mori interacted with RILP of B. mori. We then produced antibodies against RILP of B. mori in rabbits for their use in Western immunoblotting and immunohistochemistry. Western immunoblotting of brain tissue for RILP revealed a single band, at approximately 50 kD. RILP-like immunohistochemical reactivity (RILP-ir) was restricted to neurons of the pars intercerebralis and dorsolateral protocerebrum. Furthermore, RILP-ir was colocalized with the eclosion hormone-ir and bombyxin-ir. However, RILP-ir was not colocalized with prothoracicotropic hormone-ir. These results were similar to those of Rab7 from our previous study. These findings suggest that RILP and Rab7 are involved in the neurosecretion in a restricted subtype of neurons in B. mori. Thus, our study is the first to report of a possible relationship between an insect Rab effector and neurosecretion.
SPRINGER, 2014年03月, HISTOCHEMISTRY AND CELL BIOLOGY, 141 (3), 311 - 320, 英語[査読有り]
研究論文(学術雑誌)
Rab guanosine triphosphatases in eukaryotic cells are key regulators of membrane-trafficking events, such as exocytosis and endocytosis. Rab7 regulates traffic from early to late endosomes and from late endosomes to vacuoles/lysosomes. The Rab7-interacting lysosomal protein (RILP) was extracted from the silkworm, Bombyx mori (B. mori), and expressed in Escherichia coli (E. coli), followed by its purification. The glutathione sulfotransferase pull-down assay revealed that Rab7 of B. mori interacted with RILP of B. mori. We then produced antibodies against RILP of B. mori in rabbits for their use in Western immunoblotting and immunohistochemistry. Western immunoblotting of brain tissue for RILP revealed a single band, at approximately 50 kD. RILP-like immunohistochemical reactivity (RILP-ir) was restricted to neurons of the pars intercerebralis and dorsolateral protocerebrum. Furthermore, RILP-ir was colocalized with the eclosion hormone-ir and bombyxin-ir. However, RILP-ir was not colocalized with prothoracicotropic hormone-ir. These results were similar to those of Rab7 from our previous study. These findings suggest that RILP and Rab7 are involved in the neurosecretion in a restricted subtype of neurons in B. mori. Thus, our study is the first to report of a possible relationship between an insect Rab effector and neurosecretion.
SPRINGER, 2014年03月, HISTOCHEMISTRY AND CELL BIOLOGY, 141 (3), 311 - 320, 英語[査読有り]
研究論文(学術雑誌)
低分子量GTP(グアニンヌクレオチド三リン酸)結合タンパク質は,分子質量20-30kDa付近のGTP結合タンパク質の総称である。低分子量GTP結合タンパク質は,5つの主要なファミリー(Ras,Rho,Rab,ARF,Ran)に分類される(Wennerberg et al., 2005)。このうち,Rabファミリーは,最大のサブファミリーを形成し,細胞内の小胞の輸送に関与している。Rabの機能は,酵母の分泌の変異体を用いた初期の解析から明らかにされてきた(Novick et al., 1980; Salminen and Novick, 1987)。タンパク質は小胞体(endoplasmic reticulum; ER)で合成された後,ゴルジ体へ運ばれて,細胞内の小胞器官であるミトコンドリアやリソゾームへと運ばれる。また,ある種のタンパク質は細胞膜へと運ばれて,細胞外へと分泌される(exocytosis)。また,逆に細胞の外から中へ取り込まれる場合もある(endocytosis)。これらの輸送や分泌は,細胞内に存在する小胞により行われる。Rabは,これら小胞輸送の個々の段階に関与している。
日本蚕糸学会, 2014年, 蚕糸・昆虫バイオテック, 83 (1), 1_025 - 1_030, 日本語The cyclic nucleotides cGMP and cAMP have been reported to play key roles in the regulation of plant processes and responses. We have previously reported that several genes encoding flavonoid biosynthetic enzymes, including chalcone synthase (CHS) in soybean (Glycine max L), were induced by cGMP but not cAMP. The soybean genome contains nine CHS gene copies (GmCHS1-9). We investigated the responsiveness of several GmCHS genes to cGMP, CAMP, NO, and white light. Quantitative RT-PCR analysis showed that the transcript levels of GmCHS7 and GmCHS8 were increased by 3.6- and 3.8-fold, respectively, with cGMP whereas the transcript levels of GmCHS2 remained constant. Although CAMP had no effect on the transcript levels of the three genes, NO had an activation effect on all three. White light activated the three genes in a transient manner, with GmCHS2, GmCHS7, and GmCHS8 transcript levels increasing 3-fold after 3 h and decreasing to basal levels after 9 h. The GmCHS8 promoter contains several important cis-elements, including the G-box and H-box forming the Unit-I-like sequence and the MYB binding sequence, a target of the GmMYB176 transcription factor regulating the expression of GmCHS8. A transient gene expression assay revealed the activation of the Unit-I-like sequence, but not of the MYB binding sequence, by cGMP. The combination of G-box and H-box was necessary for cGMP responsiveness. Taken together, these results suggest that the Unit-I-like sequence in the promoters of GmCHS7 and GmCHS8 is a cGMP responsive cis-element in these genes and that NO exerts its effect via cis-elements other than the Unit-I-like sequence. (C) 2013 Elsevier Masson SAS. All rights reserved.
ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER, 2014年01月, PLANT PHYSIOLOGY AND BIOCHEMISTRY, 74 (1), 92 - 98, 英語[査読有り]
研究論文(学術雑誌)
多種の生体異物を代謝するヒトシトクロームP450 2A6の野生型および13種の変異型酵素をNADPH-シトクロームP450還元酵素とともに大腸菌で発現し、組換え酵素の7-エトキシクマリン、サロール、フラバノン、水酸化フラバノンの代謝を解析し、2A6ファミリーがフラボノイドを代謝することを明らかにした。
2013年11月, Biopharm Drug Dispos., 34 (2), 87 - 97, 英語[査読有り]
研究論文(学術雑誌)
Rab proteins are small GTPases that play essential roles in vesicle transport. In this study, we examined the expression of Rab proteins and neuropeptide hormones in the brain of the silkworm, Bombyx mori. We produced antibodies against B. mori Rab1 and Rab14 in rabbits. Immunoblotting of samples of brain tissue from B. mori revealed a single band for each antibody. Rab1 and Rab14 immunohistochemical labeling in the brain of B. mori was restricted to neurons of the pars intercerebralis and dorsolateral protocerebrum. Rab1, Rab7 and Rab14 co-localized with bombyxin. Rab1 and Rab7 co-localized with eclosion hormone. Rab1 co-localized with prothoracicotropic hormone. These results suggest that Rab1, Rab7 and Rab14 may be involved in neuropeptide transport in the brain of B. mori. This is the first report on the specificity of Rab proteins for the secretion of different neuropeptides in insects.
SPRINGER, 2013年02月, HISTOCHEMISTRY AND CELL BIOLOGY, 139 (2), 299 - 308, 英語[査読有り]
研究論文(学術雑誌)
Through the use of a number of bioconversion experiments we demonstrated that P450 proteins (CYP1A9 and CYP1C1) from Japanese eel (Anguilla japonica) metabolized a number of herbicides and the drug phenacetin. We performed bioconversion experiments in which substrates were added directly to incubation medium. The resulting metabolites were extracted and analyzed by high-performance liquid chromatography. Proteins CYP1A9 and CYP1C1 metabolized 50 nmol of the drug phenacetin to yield 12.1 and 1.1 nmol of product (acetaminophen), respectively. Further incubation of CYP1A9 with 50 nmol of the herbicides chlorotoluron, diuron, linuron, simazine, or atrazine yielded 16.5, 18.5, 7.3, 1.6, or 0.8 nmol of product, respectively. CYP1C1 also metabolized linuron, diuron, and simazine yield 5.4. 4.6, or 0.7 nmol of product, respectively. Next, polyclonal antibody was isolated by immunizing with two conjugated-peptides (amino acid residues 272-290 and 294-310) of CYP1A9. This antibody did not recognize human CYP1A2 or CYP1C1. Western blotting using the antibody revealed one band in the livers of Japanese eel and tilapia (Oreochromis niloticus). Theses results suggest that CYP1A9 and CYP1C1 metabolize herbicides, and that CYP1A9 is an useful biomarker of contamination when detected with this antibody. (C) 2011 Elsevier Inc. All rights reserved.
ACADEMIC PRESS INC ELSEVIER SCIENCE, 2011年10月, PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY, 101 (2), 93 - 102, 英語[査読有り]
研究論文(学術雑誌)
A number of studies have demonstrated that cytochrome P450 (P450) converts furanocoumarin derivatives into reactive molecules, which form covalent bonds to biomolecules. 5-Methoxypsoralen (5-MOP) is a natural furanocoumarin from apiaceous plants. In this study, we examined the effect on 5-MOP metabolism of single nucleotide polymorphisms (SNPs) in CYP2A13. We used Escherichia coli-generated recombinant enzymes of wild-type CYP2A13(star)1 and five variants, CYP2A13(star)4 (R101Q), CYP2A13(star)5 (F453Y), CYP2A13(star)6 (R494C), CYP2A13(star)8 (D158E), and CYP2A13(star)9 (V323L). In high-performance liquid chromatography analyses of 5-MOP metabolic products, CYP2A13(star)1 converted 5-MOP into 5-MOP dihydrodiol; K(m) and V(max) values of the reaction were 1.44 +/- 0.17 mu M and 4.23 +/- 0.36 nmol/(min . nmol P450), respectively. The generation of a dihydrodiol from 5-MOP implies that conversion by CYP2A13 causes toxicity due to the formation of covalent bonds with DNA or proteins. Most of the CYP2A13 variants could metabolize 5-MOP; K(m) values for CYP2A13(star)5, (star)6, (star)8, and (star)9 were 1.63 +/- 0.12, 1.36 +/- 0.10, 0.85 +/- 0.09, and 0.58 +/- 0.06 mu M, respectively, and V(max) values were 3.20 +/- 0.13, 4.69 +/- 0.13, 2.34 +/- 0.07, and 1.84 +/- 0.09 nmol/(min . nmol P450), respectively. However, the processing of 5-MOP by CYP2A13(star)4 was not detectable. Based on this data, we hypothesize that SNPs within the CYP2A13 gene affect metabolism of 5-MOP in humans.
AMER SOC PHARMACOLOGY EXPERIMENTAL THERAPEUTICS, 2010年12月, DRUG METABOLISM AND DISPOSITION, 38 (12), 2110 - 2116, 英語[査読有り]
研究論文(学術雑誌)
Small GTPases of the Rab family are key regulators of membrane trafficking. We produced antibodies against the Rab7 protein of Bombyx mori (BRab7) in rabbits, and against the Rab11 protein of B. mori (BRab11) in mice. The antibodies recognized BRab7 and BRab11 proteins, but did not recognize other Rab proteins. Immunoblotting of samples from brain tissue of B. mori revealed a single band for each antibody. Rab11 was expressed in most tissues, whereas Rab7 was expressed in the brain, ovary, and testis. Immunohistochemical reactivity of Rab7 and Rab11 in the brain of B. mori was restricted to neurons of the pars intercerebralis and dorsolateral protocerebrum. Double-labeling experiments demonstrated that immunohistochemical reactivity of Rab7 co-localized with that of Rab11 and partially with that of Rab8. Immunohistochemical reactivity of Rab11 and Rab8 co-localized with that of PERIOD, one of the proteins associated with circadian rhythm. These findings suggest that Rab7, Rab8, and Rab11 are involved in protein transport in the neurons of the brain of B. mori and might play a role in the control of circadian rhythm.
SPRINGER, 2010年12月, HISTOCHEMISTRY AND CELL BIOLOGY, 134 (6), 615 - 622, 英語[査読有り]
研究論文(学術雑誌)
Cucumisin is a subtilisin-like serine protease (subtilase) that is found in the juice of melon fruits (Cucumis melo L.). It is synthesized as a preproprotein consisting of a signal peptide, NH(2)-terminal propeptide, and 67-kDa protease domain. We investigated the role of this propeptide (88 residues) in the cucumisin precursor. Complementary DNAs encoding the propeptides of cucumisin, two other plant subtilases (Arabidopsis ARA12 and rice RSP1), and bacterial subtilisin E were expressed in Escherichia coli independently of their mature enzymes. The cucumisin propeptide strongly inhibited cucumisin in a competitive manner with a K(i) value of 6.2 +/- 0.55 nM. Interestingly, cucumisin was also strongly inhibited by ARA12 and RSP1 propeptides but not by the subtilisin E propeptide. In contrast, the propeptides of cucumisin, ARA12, and RSP1 did not inhibit subtilisin. Deletion analysis clearly showed that two hydrophobic regions, Asn(32)-Met(38) and Gly(97)-Leu(103), in the cucumisin propeptide were important for its inhibitory activity. Site-directed mutagenesis also confirmed the role of a Val(36)-centerd hydrophobic cluster within the Asn(32)-Met(38) region in cucumisin inhibition. Circular dichroism spectroscopy revealed that the cucumisin propeptide had a secondary structure without a cognate protease domain and that the thermal unfolding of the propeptide at 90 degrees C was only partial and reversible. A tripeptide, Ile(35)-Val(36)-Tyr(37), in the Asn(32)-Met(38) region was thought to contribute toward the formation of a proper secondary structure necessary for cucumisin inhibition. This is the first report on the function and structural information of the propeptide of a plant serine protease.
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 2010年09月, JOURNAL OF BIOLOGICAL CHEMISTRY, 285 (39), 29797 - 29807, 英語[査読有り]
研究論文(学術雑誌)
Rab GTPases are essential for vesicular transport, whereas adenosine triphosphate (ATP) is the most important and versatile of the activated carriers in the cell. But there are little reports to clarify the connection between ATP and Rab GTPases. A cDNA clone (Rab14) from Bombyx mori was expressed in Escherichia coli as a glutathione S-transferase fusion protein and purified. The protein bound to [H-3]-GDP and [S-35]-GTPgS. Binding of [S-35]-GTP gamma S was inhibited by guanosine diphosphate (GDP), guanosine triphosphate (GTP) and ATP. Rab14 showed GTP- and ATP-hydrolysis activity. The Km value of Rab14 for ATP was lower than that for GTP. Human Rab14 also showed an ATPase activity. Furthermore, bound [H-3]-GDP was exchanged efficiently with GTP and ATP. These results suggest that Rab14 is an ATPase as well as GTPase and gives Rab14 an exciting integrative function between cell metabolic status and membrane trafficking.
ROYAL SOC, 2010年06月, BIOLOGY LETTERS, 6 (3), 379 - 381, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
Symmetric chloroplast division requires a prokaryote-derived division regulator protein MinD, whose subchloroplastic localization remains to be completely established. We investigated the localization and functionality of AtMinD1 (Arabidopsis thaliana MinD) fused with a dual hemagglutinin epitope (dHA) or a yellow fluorescent protein (YFP). AtMinD1-dHA, which successfully complemented the arc11/atminD1 mutant phenotype, was predominantly located at the envelope membrane and the mid-chloroplast constriction site. Meanwhile, AtMinD1-YFP was non-functional and showed suborganellar localization partly similar to that of AtMinD1-dHA. This prompts us to reevaluate earlier transgenic and transient expression studies using fluorescent protein-tagged AtMinD1.
TAYLOR & FRANCIS LTD, 2009年07月, BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 73 (7), 1693 - 1697, 英語[査読有り]
研究論文(学術雑誌)
Small GTPases of the Rab family act as essential regulators of vesicle transport pathways, including the exocytosis of neurohormones. These processes are not well-understood in insects. To address the physiological function of Rab proteins and their phosphorylation in insect neurosecretion, Rab8-like, prothoracicotropic hormone (PTTH)-like, and protein kinase C (PKC)-like immunohistochemical reactivities (-ir) were investigated in the brain of the American cockroach, Periplaneta americana. All the antibodies tested reacted with neurons in the pars intercerebralis, corpora cardiaca, and nervi corporis allati I. Double-labeling experiments demonstrated that all PTTH-ir were colocalized with Rab8-ir and PKC-ir in the pars intercerebralis, although exclusive reactivity was present to antisera against Rab8 or PKC. These findings support the notion that Rab8-like antigen is phosphorylated by PKC, and that this phosphorylation is involved in the axonal transport and secretion of PTTH in this species.
SPRINGER, 2009年03月, CELL AND TISSUE RESEARCH, 335 (3), 607 - 615, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
Small GTPases of the Rab family act as essential regulators of vesicle transport pathways. Five Rab cDNA clones (BRab1, 7, 8, 11 and 14) from Bombyx mori were expressed in Escherichia coli as a thioredxin or glutathione sulfotransferase fusion protein. After purification, the fusion protein was tested for phosphorylation using protein kinase C (PKC). Results indicate that all of them were phosphorylated in vitro. The phosphorylation site of BRab1 was determined by mass-spectrometric analysis, which identified that Ser-17 of BRab1 was phosphorylated by PKC. Deletion and site-directed mutagenesis indicated that Ser-111 of BRab8, in addition to Ser-17, was newly phosphorylated. Further immunohistochemical analysis using antibodies against Rab8 indicated that there are some Rab8 immunoreactive cells close to the neuropeptide secreting cells. This result suggests that in insects Rab proteins are regulated by phosphorylation and at least some of them are involved in neuropeptide secretion.
CZECH ACAD SCI, INST ENTOMOLOGY, 2009年, EUROPEAN JOURNAL OF ENTOMOLOGY, 106 (4), 499 - 506, 英語[査読有り]
研究論文(学術雑誌)
The traditional Japanese alcoholic beverage sake is produced by fermentation of rice by Saccharomyces cerevisiae and Aspergillus oryzae. A. oryzae releases ferulic acid. an antioxidant, from steamed rice during the fermentation process. The concentration of ferulic acid increased with time during fermentation and the production rate peaked 9-12 days post inoculation. Analysis of the fermentation cultures of Aspergillus oryzae, by high-performance liquid chromatography (HPLC), revealed that p-coumaric acid induced an 18.9-fold increase in the level of ferulic acid. Furthermore, SDS-PAGE analysis revealed an increase or decrease in the level of specific proteins after the addition of p-coumaric acid to fermentation Cultures of Aspergillus oryzae. Ferulate esterase (FAE) activity was observed in the fermented sake ten days following the start of the fermentation process. These results suggest that the level of ferulic acid is regulated by the enzymes synthesized by A. oryzae during the sake brewing process.
INST BREWING, 2009年, JOURNAL OF THE INSTITUTE OF BREWING, 115 (2), 116 - 121, 英語[査読有り]
研究論文(学術雑誌)
P450 (cytochrome P450) enzymes catalyse the mono-oxygenation of a wide range of compounds such as steroids, fatty acids, vitamins and drugs. In the present paper we demonstrate a system for bioconverting diverse compounds [flavanone, DHEA (dehydroepiandrosterone) and 7-ethoxycoumarin] using P450 species expressed in Escherichia coli. First, we expressed four P450 species: rabbit CYP2B (MO family 2, subfamily B), fruitfly (Drosophila) CYP317A, rat CYP3A23 and mouse CYP2J5. Next, we added substrates directly to the incubation medium. The resulting metabolites were extracted and analysed by HPLC and spectrofluorimetry. The first substrate, 7-ethoxycoumarin, was de-ethylated by CYP2B; CYP2J5 and CYP3A23 showed weak activity, and CYP317A had no activity for 7-ethoxycoumarin. We next used flavanone, a flavonoid, as a substrate for these four MO species and other P450 species expressed previously. As a result, CYP2B, CYP2C43 and CYP2C29 catalysed flavanone 2-hydroxylation. CYP2A5 catalysed 2- and 4-hydroxylations. Finally, to produce diverse modified compounds, variants of CYP2A5 with point mutations were incubated with a steroid (DHEA) and an antioxidant (flavanone) in vivo. HPLC analysis indicated that two P450 species produced a 7-beta-hydroxy-DHEA and two P450 species produced a 2-alpha-hydroxy-DHEA. Four P450 species catalysed flavanone 2- and 4-hydroxylations. These results indicate that bioconversion by P450 is a useful technique to modify small molecules (steroids, coumarin and flavanone) and produce new, diverse hydroxylated compounds, which could be used for high-throughput screening for drug discovery.
WILEY, 2008年08月, BIOTECHNOLOGY AND APPLIED BIOCHEMISTRY, 50, 165 - 171, 英語[査読有り]
研究論文(学術雑誌)
We indicated that two P450s (1A9 and 1C1) from Japanese eel (Anguilla japonica) metabolized 7-ethoxycoumarin, 7-ethoxyresorufin, and flavanone. At first, we constructed expression vectors for two types of P450 (1A9 and 1C1). The reduced CO-difference spectra of Escherichia coli cells transformed with these plasmids showed Soret peaks (450 nm) that were typical of P450s. We performed bioconversion experiments in which substrates were added directly to incubation medium. The resulting metabolite(s) were extracted and analyzed by high-performance liquid chromatography and spectrofluorometer. Incubation of 50 nmol 7-ethoxyresorufin with P450 1C1 yielded 0.773 nmol of deethylated product, whereas 50 nmol 7-ethoxycoumarin resulted in 4.76 nmol. P450 1A9 metabolized 50 nmol of 7-ethoxyresorufin and 7-ethoxycoumarin to yield 6.54 and 20.9 nmol of deethylated product, respectively. Incubation of 50 nmol flavanone with P450 1C1 yielded 1.46 nmol and 0.69 nmol of products, whereas 50 mnol flavanone with P450 1A9 resulted in 1.10 nmol. In this system, 4'-hydroxy flavanones were formed by P450 1A9 and P450 1C1. P450 1A9 also metabolized 50 nmol of 17 beta-estradiol to yield 4.25 nmol of product. In this system, 2-hydroxy estradiol was formed by P450 1A9 using 17 beta-estradiol as a substrate. This study is the first to identify the substrates that P450 1C1 and 1A9 metabolize. (c) 2007 Elsevier Inc. All rights reserved.
ELSEVIER SCIENCE INC, 2008年04月, COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY & PHARMACOLOGY, 147 (3), 278 - 285, 英語[査読有り]
研究論文(学術雑誌)
Small GTPases of the Rab family are key regulators of membrane trafficking. Monoclonal antibodies are useful tools for identifying proteins that interact with other proteins and for examining their tissue distribution. We selected a monoclonal antibody against Rab8 of Bombyx Mori L. It specifically recognized amino acid residues 30-109, which are conserved among Rab8 proteins, and did not recognize any other Rab proteins. Western blotting using the antibody revealed one band in the brains of B. Mori and rat. Far-Western blotting analysis detected three proteins interacting with Rab8. These results indicate that this antibody is useful for clarifying the physiological function of Rab8 of B. Mori and other species. This is a report of a study on a monoclonal antibody against insect Rab protein.
CZECH ACAD SCI, INST ENTOMOLOGY, 2007年10月, EUROPEAN JOURNAL OF ENTOMOLOGY, 104 (4), 641 - 645, 英語[査読有り]
研究論文(学術雑誌)
The Rob family of small GTPases are key regulators of membrane trafficking. Partially purified ROB from Bombyx mori (BRab8) was phosphorylated by protein kinase C in mammalian cells in vitro. To determine which of the seven serines and four threonines are phosphorylated, we generated deletion and site-directed mutants of BRab8, inserted them in Escherichia coli, partially purified the encoded fusion proteins by affinity chromatography, and examined their phosphorylation by protein kinase C in vitro. We found that Ser-132 of BRab8 was specifically phosphorylated by protein kinase C. In addition, Western blotting using an antiserum against BRab8 and in-gel staining for phosphorylated proteins revealed that BOB is phosphorylated in vivo.
WILEY-BLACKWELL, 2007年10月, ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY, 66 (2), 89 - 97, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(研究会,シンポジウム資料等)
[査読有り]
研究論文(研究会,シンポジウム資料等)
[査読有り]
[査読有り]
研究論文(学術雑誌)
We developed a system for bioconverting diverse compounds using P450s produced in Escherichia coli. Vectors for the expressing various P450 cDNAs quickly and easily in E. coli were developed by using several restriction enzyme sites. Three types of P450 (2C2, 2C29, and 2D22) were produced using these plasmids. Substrates were directly added to the incubation medium and metabolized. To obtain pure product from the medium, we first tried production of P450 in synthetic medium. The amount of another P450 2C43 produced in the synthetic medium was similar to the amount produced in Luria broth (LB) medium. Next, estradiol, a steroid, was added as a substrate, incubated, and the metabolite was extracted and analyzed by high-performance liquid chromatography. The metabolite extracted from synthetic medium was purer than that obtained from LB medium. Three P450s (2C29, 2C2, and 2A4) metabolized testosterone at different positions. P450 2C29 metabolized 7-ethoxycournarin, androstendione, and dehydroepiandrosterone in this medium. P450s produced in the synthetic medium may be useful for producing various modified compounds for high-throughput screening.
SPRINGER HEIDELBERG, 2006年12月, JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY, 33 (12), 1043 - 1050, 英語[査読有り]
研究論文(学術雑誌)
The complete nucleotide sequences of the cDNA and its gene that encode a bifunctional alpha-amylase/subtilisin inhibitor of rice (Oryza sativa L.) (RASI) were analyzed. RASI cDNA (939 lip) encoded a 200-residue polypeptide with a molecular mass of 21,417 Da, including a signal peptide of 22 amino acids. Sequence comparison and phylogenetic analysis showed that RASI is closely related to alpha-amylase/subtilisin inhibitors from barley and wheat. RASI was found to be expressed only in seeds, suggesting that it has a seed-specific function. A coding region of RASI cDNA without the signal peptide was introduced into Escherichia coli and was expressed as a His-tagged protein. Recombinant RASI was purified to homogeneity in a single step by Ni-chelating affinity column chromatography and characterized to elucidate the target enzyme. The recombinant inhibitor had strong inhibitory activity toward subtilisin, with an equimolar relationship, comparable with that of native RASI, and weak inhibitory activity toward some microbial alpha-amylases, but not toward animal or insect alpha-amylases. These results suggest that RASI might function in the defense of the seed against microorganisms.
TAYLOR & FRANCIS LTD, 2006年05月, Biosci. Biotech. Biochem., 70 (5), 1200 - 1209, 英語[査読有り]
研究論文(学術雑誌)
Two partial cDNA clones (Protein kinase C alpha and Protein kinase C iota), each of which encoded a different member of PKC-protein family, were isolated using RT-PCR from mRNA of Bombyx mori. The full-length cDNAs were isolated using SMART-RACE. The cDNAs were expressed in HepG2 cells and the recombinant proteins were partially purified using an affinity chromatography. Protein kinase C alpha (BPKC alpha) showed a calcium-dependent kinase activity of histones. Whereas protein kinase C iota (BPKC iota) showed a calcium-independent activity. Bisindolyl maleimide 1, a PKC inhibitor, inhibited these kinase activities. Furthermore, in vitro BPKC alpha interacted and phosphorylated two proteins expressed in the brain of Bombyx mori. Rob protein, which plays important roles in the vesicle transport in the brain, and bMBD2/3, which is a methyl DNA-binding protein and regulates transcription. These results suggest that these PKCs phosphorylate various substrate proteins and function in the brain of Bombyx mori.
WILEY-BLACKWELL, 2006年02月, ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY, 61 (2), 65 - 76, 英語[査読有り]
研究論文(学術雑誌)
The small GTPases known as Rab proteins are key regulators of membrane trafficking. We used RT-PCR to isolate cDNA clones of insect-specific Rab proteins (BRabN1 and BRabN2) showing low homology with known Rab proteins from other animals, from mRNA of Bombyx mori. These 2 Rabs were produced in Escherichia coli and purified. BRabN1 bound [(3)H]-GDP and [(35)S]-GTPgammaS with dis
2006年, Archives of Insect Biochemistry and Physiology, 70, 77 - 89, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
Suppression-subtractive hybridization was used to isolate cDNAs specifically expressed in the brain at the termination of pupal diapause in Agrius convolvuli. One of the isolated clones shows similarity to the cytochrome c oxidase subunit I (COX1) gene. The full-length cDNA was obtained from brain mRNA by rapid amplification of cDNA ends (RACE). The insert is 1.65 kb in length and has an open reading frame of 1.46 kb which encodes a putative protein of 486 amino acid residues. RT-PCR reveals that the mRNA increases dramatically at an early stage of diapause termination. Activity of cytochrome c oxidase in the brain also increases at the same time. The up-regulation of this gene suggests that expression of the COX1 gene and ATP synthesis are initiated in the brain in association with diapause termination. (C) 2003 Elsevier Ltd. All rights reserved.
PERGAMON-ELSEVIER SCIENCE LTD, 2004年01月, JOURNAL OF INSECT PHYSIOLOGY, 50 (1), 35 - 42, 英語研究論文(学術雑誌)
From a mRNA of the brain of Bombyx mori, we isolated 8 cDNA clones (BRabs), each of which encodes a different member of Rob-protein family. Four of them have more than 80% amino acid identity to the corresponding members of Drosophila Rob proteins. The other 4 proteins show low sequence similarity to any of the known Rob proteins. However, all of them contain the region conserved in rob protein. Using RACE (Rapid Amplification of cDNA ends), the one full-length cDNA clone (BRab14) was isolated. The clone was expressed in Escherichia coli as a glutathione S-transferase (GST) fusion protein. After purification, the fusion protein was cut with protease to remove GST-Tag and applied to a glutathione S-Sepharose column. The protein bound [H-3]-GDP with association constant of 1.02 x 10(11) M-1. Further, the protein was phosphorylated by protein kinase. This result suggests that Rob protein in the brain of Bombyx mori binds GDP or GTP and its function is regulated by phosphorylation.
WILEY-LISS, 2003年03月, ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY, 52 (3), 130 - 138, 英語研究論文(学術雑誌)
The phosphatase of a psychrophile (Shewanella sp.) was purified by ammonium sulfate fractionation, followed by sequential column chromatographies. The purified enzyme was electrophoretically homogeneous on native- and SDS-PAGE. Its molecular weight was 41,826 by its amino acid composition. The enzyme had its optimal pH for the activity at 9.8, and a broad substrate specificity to dephosphorylate ATP, pyrophosphate, glycerophosphate, and so on. Its activity was increased by metal ions including Mg2+, Mn2+, and Co2+. The maximal activity was observed at 40 degrees C, and the enzyme at 0 degrees C showed 39% of activity at 40 degrees C. The enzyme, however, tended to lose its activity at 20 degrees C and pH 9.8. These results indicated that purified enzyme was an alkaline phosphatase with characteristics; high catalytic efficiency at low temperature and gradual inactivation at an intermediate temperature.
TAYLOR & FRANCIS LTD, 1998年11月, BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 62 (11), 2246 - 2250, 英語[査読有り]
研究論文(学術雑誌)
From a brain cDNA library of Bombyx mori, we cloned cDNA for BRab, which encoded a 202-amino-acid polypeptide sharing 60-80% similarity with rab1 family members. To characterize its biochemical properties, cDNA for BRab was inserted into an expression vector (pGEX2T) and expressed in Escherichia coli as a glutathione S-trans-ferase (GST) fusion protein. The recombinant protein was purified to homogeneity with glutathione S-Sepharose. The purified GST-BRab bound [^<35>S]-GTPγS and [^3H]-GDP with association constants of 1.5×10^6M^<-1> and 0.58×10^6M^<-1>, respectively. The binding of [^<35>S]-GTPγS was inhibited with GTP and GDP, but with no other nucleotides. The GTP-hydrolysis activity was evaluated to be 5 m mole/min/mole of BRab. In the presence of 6 mM MgCl_2,bound [^<35>S]-GTPγS and [^3H]-GDP were exchanged with GTPγS most efficiently. These results suggest that BRab, having a higher affinity for GTP than GDP, converts from the GTP-bound state into the GDP-bound state by intrinsic GTP hydrolysis activity and returns to the GTP-bound state with the exchange of GDP with GTP.
社団法人日本農芸化学会, 1998年10月23日, Bioscience, biotechnology, and biochemistry, 62 (10), 1885 - 1891, 英語The phosphatase of a psychrophile was purified by ammonium sulfate fractionation, and a sequence of chromatographies on DEAE-Cellulofine, butyl-Cellulofine, Sephacryl S-100, and Mono-Q columns, The purified enzyme preparation was found to be electrophoretically homogeneous on native-and SDS-PAGE, and its molecular mass was determined to be 38.4 kDa by MALDI-TOF mass spectrometry, Maximal activity was observed at 30 degrees C and pH 6.0, Furthermore, the activity of this enzyme at 0 and 5 degrees was 27 and 28%, respectively, of that at 30 degrees C, The enzyme was stable in the pH range of 6.0 to 8.0 and up to 20 degrees C. The enzyme was affected by metal ions; the activity was enhanced by Mg2+ and Ca2+ ions, but depressed by Zn2+ ions, Analysis of the amino acid composition indicated that this phosphatase contains no S-S bond, and only a few prolyl residues necessary to retain the rigid structure of a protein molecule, The phosphatase shows typical features of a cold enzyme; high catalytic activity at low temperature and rapid inactivation at an intermediate temperature.
JAPANESE BIOCHEMICAL SOC, 1998年02月, JOURNAL OF BIOCHEMISTRY, 123 (2), 219 - 225, 英語[査読有り]
研究論文(学術雑誌)
cDNA for chimeric protein, P450(3P4), consisting of the amino-terminal 43 residues (the membrane-anchor region) of rabbit P450IIC14 and the remaining 447 residues of rabbit P450IIE1 was constructed, then cloned into expression vector pAAH5, and expressed in Saccharomyces cerevisiae AH22 cells under the control of yeast ADH1 promoter. P450(3P4) thus synthesized in the transformed yeast cells was partially purified, and its spectral and catalytic properties were examined. In the oxidized state P450(3P4) exhibited a high-spin type absorption spectrum even in the absence of a substrate. The reduced CO complex of the P450 showed a Soret absorption maximum at 452 nm. P450(3P4) catalyzed aniline p-hydroxylation, N-nitrosodimethylamine demethylation, benzphetamine N-demethylation, and laurate and caprate (ω-1)-hydroxylation in the reconstituted system containing the P450 and NADPH-P450 reductase. These results indicate that P450(3P4) preparation obtained from the transformed yeast cells has spectral and catalytic characteristics identical with those of P450IIE1 purified from rabbit liver microsomes, confirming the substrate specificity reported of P450IIE1. © 1990 Copyright, 1990 by the Journal of Biochemistry.
Oxford University Press, 1990年, Journal of Biochemistry, 108 (4), 522 - 524, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
記事・総説・解説・論説等(学術雑誌)
Cytochrome P450 (CYP) enzymes are members of the hemoprotein superfamily, and are involved in the mono-oxygenation reactions of a wide range of endogenous and exogenous compounds in mammals and plants. Characterization of CYP genes in fish has been carried out intensively over the last 20 years. In Japanese pufferfish (Takifugu rubripes), 54 genes encoding P450s have been identified. Across all species of fish, 137 genes encoding P450s have been identified. These genes are classified into 18 CYP families: namely, CYP1, CYP2, CYP3, CYP4, CYP5, CYP7, CYP8, CYP11, CYP17, CYP19, CYP20, CYP21, CYP24, CYP26, CYP27, CYP39, CYP46 and CYP51. We pinpointed eight CYP families: namely, CYP1, CYP2, CYP3, CYP4, CYP11, CYP17, CYP19 and CYP26 in this review because these CYP families are studied in detail. Studies of fish P450s have provided insights into the regulation of P450 genes by environmental stresses including water pollution. In this review, we present an overview of the CYP families in fish. (C) 2012 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2012年07月, ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY, 34 (1), 1 - 13, 英語[査読有り]
書評論文,書評,文献紹介等
研究発表ペーパー・要旨(国際会議)
研究発表ペーパー・要旨(国際会議)
研究発表ペーパー・要旨(国際会議)
The nucleotide sequence of cDNA for rabbit liver cytochrome P-450 (laurate (ω-1)-hydroxylase) was replaced with that for rabbit liver cytochrome P-450 (testosterone 16α-hydroxylase) in various regions coding for the amino acid sequence between residues 43 and 261. Six chimeric cDNAs thus constructed were cloned into expression vector pAAH5, and expressed in Saccharomyces cerevisiae AH22 cells under the control of yeast ADH1 promoter. Chimeric P-450s synthesized in the transformed yeast cells were purified partially and their catalytic and spectral properties were examined and compared with those of the chimeric P-450 which is considered to possess the same catalytic properties as the wild-type P-450. In the oxidized state the chimeric P-450s exhibited a low- and high-spin mixed-type absorption spectrum of cytochrome P-450 and the spectrum was converted to a typical high-spin type on addition of laurate or caprate, indicating the binding-of the fatty acids to the substrate site of the chimeric P-450s. However, the affinities of the fatty acids for the chimeras devoid of the sequence of P-450 (laurate (ω-1)-hydroxylase) in either of the regions spanning residues 90-125 and 210-261 were 10 to 20 times lower than those for the chimeras containing the sequence of the wild-type P-450 in both regions. The latter chimeras have about the same affinities as the chimera which is essentially the wild-type P-450. In the reconstituted system containing purified enzymes, the chimeras containing the sequence of the wild-type P-450 in both regions catalyzed (ω-1)-hydroxylation of the fatty acids, but their activities were 51-67% of that of the chimera which is essentially the wild-type P-450. The chimera which contains the sequence of the wild-type P-450 in the region covering residues 90-125 but not residues 210-261 was about one-tenth as active as the chimera which is essentially the wild-type P-450. On the other hand, the chimeras devoid of the sequence of the wild-type P-450 in the region spanning residues 90-125 were completely devoid of the hydroxylase activities. These results indicate that two segments of P-450 (laurate (ω-1)-hydroxylase) covering residues 90-125 and 210-262 constitute the substrate binding sites and cooperate to fix the fatty acid at an appropriate position on the P-450 molecule, and the former segment is essential to the hydroxylase activity. The reduced CO complex of the chimeric P-450s showed the typical absorption spectrum of cytochrome P-450. However, the CO complexes of the chimeras devoid of the sequence of the wild-type P-450 covering residues 90-125 were much more unstable to denaturation than those containing this sequence, suggesting that this sequence protects the conformation of the chimeric P-450s in the reduced state against denaturation.
The Japanese Biochemical Society, 1989年, The Journal of Biochemistry, 106 (4), 569 - 574, 英語口頭発表(一般)
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