Faculty Profiles - TAMURA Takashi

Papers - TAMURA Takashi

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3.好熱好酸性古細菌Sulfolobus tokodaii由来シスタチオニンγ-シンターゼ(第410回研究協議会研究発表要旨,ビタミンB研究委員会)

柳谷昌彦, 田村隆, 稲垣賢二

ビタミン 82 ( 1 ) 61 - 61 2008

3. Cellulomonas属細菌由来のグリセロールキナーゼの特性と立体構造解析(第407回研究協議会研究発表要旨,ビタミンB研究委員会)

稲垣賢二, 田村隆, 曽我部敦

ビタミン 81 ( 5 ) 258 - 259 2007

8.抗腫瘍性B_6酵素L-メチオニンγ-リアーゼにおけるCys116の役割(第398回ビタミンB研究委員会研究発表要旨)

工藤大蔵, 田村隆, 稲垣賢二

ビタミン 79 ( 1 ) 43 - 44 2005

16.硫黄酸化細菌A.thiooxidansのNAD^+依存型イソクエン酸脱水素酵素(ビタミンB研究委員会第399回研究協議会研究発表要旨)

稲垣賢二, 田村隆

ビタミン 79 ( 3 ) 194 - 194 2005

1P036 Implication for reaction mechanism of bacterial NAD dependent isocitrate dehydrogenase based on crystal structure and quantum chemistry

Imada K., Tamura T., Takenaka R., Kobayashi I., Inagaki K., Namba K.

Seibutsu Butsuri 45 S40 2005

Identification of thermoacidophilic bacteria and a new Alicyclobacillus genomic species isolated from acidic environments in Japan Reviewed

K Goto, Y Tanimoto, T Tamura, K Mochida, D Arai, M Asahara, M Suzuki, H Tanaka, K Inagaki

EXTREMOPHILES 6 ( 4 ) 333 - 340 2002.8

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER-VERLAG TOKYO

Sixty strains of thermoacidophilic bacteria have been isolated from soil and water samples obtained from various acidic environments in Japan. An initial comparative sequence analysis of the hypervariable regions of the 16S rDNA revealed that all strains could be assigned to the Alicyclobacillus acidocaldarius-Alicyclobacillus genomic species 1 group, which could be further subdivided into three clusters (Clusters I-III). On the basis of phenotypic characteristics, chemotaxonomic profiles, and phylogenetic data of six selected strains, five strains were identified as either A. acidocaldarius or Alicyclobacillus genomic species 1; however, one strain (MIH 332) could not be determined to belong to either of these species. 16S rDNA sequence homology values between strain MIH 332 and the reference strains of A. acidocaldarius (ATCC 27009(T)) and Alicyclobacillus genomic species 1 (DSM 11984) were 98.8% and 99.1%, respectively, which were higher than the corresponding similarity between the reference strains (98.4%). On the other hand, DNA-DNA hybridization levels between strain MIH 332 and the reference strains were 39% and 44%, respectively, which were lower than the value between the reference strains (59% or 65%). However, the phenotype of strain MIH 332 was also similar to those of the reference strains, and a typical phenotype could not be found for the strain, thus indicating that the strain may be a new genomic species of A. acidocaldarius, for which the name Alicyclobacillus genomic species 2 is tentatively proposed. The results of this study suggest that A. acidocaldarius and its related species are widely distributed in acidic environments in Japan, with slight regional variations in morphological and genotypic characteristics.

DOI： 10.1007/s00792-001-0262-3

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Role of tyrosine 114 of L-methionine y-lyase from Pseudomonas putida

H Inoue, K Inagaki, N Adachi, T Tamura, N Esaki, K Soda, H Tanaka

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 64 ( 11 ) 2336 - 2343 2000.11

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

L-Methionine gamma -lyase from Pseudomonas putida has a conserved tyrosine residue (Tyr114) in the active site as in all known sequences of gamma -family pyridoxal 5'-phosphate dependent enzymes. A mutant form of L-methionine gamma -lyase in which Tyr114 was replaced by phenylalanine (Y114F) resulted in 910-fold decrease in k(cat) for alpha,gamma -elimination of L-methionine, while the K-m remained the same as the wild type enzyme. The Y114F mutant had the reduced k(cat) by only 28- and 16-fold for substrates with an electron-withdrawing group at the gamma -position, namely O-acetyl-L-homoserine and L-methionine sulfone, respectively, and also the similar reduction of k(cat) for alpha,beta -elimination and deamination substrates. The hydrogen exchange reactions of substrate and the spectral changes of the substrate-enzyme complex catalyzed by the mutant enzyme suggested that gamma -elimination process for L-methionine is the rate-limiting determination step in alpha,gamma -elimination overall reaction of the Y114F mutant. These results indicate that Tyr114 of L-methionine gamma -lyase is important in gamma -elimination of the substrate.

DOI： 10.1271/bbb.64.2336

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Crystal structure of the pyridoxal 5 '-phosphate dependent L-methionine gamma-lyase from Pseudomonas putida

H Motoshima, K Inagaki, T Kumasaka, M Furuichi, H Inoue, T Tamura, N Esaki, K Soda, N Tanaka, M Yamamoto, H Tanaka

JOURNAL OF BIOCHEMISTRY 128 ( 3 ) 349 - 354 2000.9

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPANESE BIOCHEMICAL SOC

L-Methionine gamma-lyase (MGL) catalyzes the pyridoxal 5'-phosphate (PLP) dependent alpha,gamma-elimination of L-methionine. We have determined two crystal structures of MGL from Pseudomonas putida using MAD (multiwavelength anomalous diffraction) and molecular replacement methods. The structures have been refined to an R-factor of 21.1% at 2.0 and 1.7 Angstrom resolution using synchrotron radiation diffraction data. A homotetramer with 222 symmetry is built up by non-crystallographic symmetry. Two monomers associate to build the active dimer. The spatial fold of subunits, with three functionally distinct domains and their quarternary arrangement, is similar to those of L-cystathionine beta-lyase and L-cystathionine gamma-synthase from Escherichia coli.

DOI： 10.1093/oxfordjournals.jbchem.a022760

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Noncompetitive, reversible inhibition of aminoacylase-1 by a series of L-alpha-hydroxyl and L-alpha-fluoro fatty acids: Ligand specificity of Aspergillus oryzae and porcine kidney enzymes

T Tamura, Y Oki, A Yoshida, T Kuriyama, H Kawakami, H Inoue, K Inagaki, H Tanaka

ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 379 ( 2 ) 261 - 266 2000.7

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC

L-Lactate and L-beta-phenyllactate have been identified in the culture broth of Streptomyces sp. KY-11 as reversible noncompetitive inhibitors of Aspergillus oryzae aminoacylase-l and porcine kidney aminoacylase I. A series of alpha-hydroxyl acids (DL-R-CH(OH)-COOH, R = Et, n-pro, n-butyl, n-pentyl, n-hexyl) also inhibited the two enzymes in reversible noncompetitive kinetics, and the inhibition potency (-log K-i) increased with the increased hydrophobicity of the R group. The two eukaryotic enzymes showed distinct preferences to the ligand alpha-alkyl group, and the fungus enzyme was inhibited by L-beta-phenyllactate (R = benzyl) 10(3)-fold more potently than the mammalian enzyme. L-alpha-Fluoro-beta-phenyl-propionate and its D-isomer were used to show that the L-configuration of the alpha-substituent was important for potent inhibition of both the enzymes. The fungus aminoacylase-1 steeply decreased the affinity to alpha-fluoro-and alpha-hydroxy-n-caproate as pH was raised from 7 to 11, whereas the mammalian enzyme retained the affinity to these ligands under alkaline conditions. These results suggest that A. oryzae aminoacylase-1 has an acidic residue that interacts with OH or -F, while the mammalian enzyme would have a basic residue that recognizes the alpha-substituents. (C) 2000 Academic Press.

DOI： 10.1006/abbi.2000.1869

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Purification of Anti-Escherichia Coli O-157 components produced by Enterococcus faecalis THIO, an isolate from Malaysian fermentation food, tempeh

Ohhira, I, T. Tamura, H. Kurokawa, H. Nakaue, K. Inagaki, H. Tanaka

Milk Science 49 ( 2 ) 81 - 88 2000

Molecular characterization of the mde operon involved in L-methionine catabolism of Pseudomonas putida Reviewed

H Inoue, K Inagaki, SI Eriguchi, T Tamura, N Esaki, K Soda, H Tanaka

JOURNAL OF BACTERIOLOGY 179 ( 12 ) 3956 - 3962 1997.6

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC MICROBIOLOGY

A 15-kb region of Pseudomonas putida chromosomal DNA containing the mde operon and an upstream regulatory gene (mdeR) has been cloned and sequenced. The mde operon contains two structural genes involved in L-methionine degradative metabolism: the already-identified mdeA, which encodes L-methionine gamma-lyase (H. Inoue, K. Inagaki, M. Sugimoto, N. Esaki, K. Soda, and fi, Tanaka, J. Biochem, (Tokyo) 117:1120-1125, 1995), and mdeB, which encodes a homologous protein to the homodimeric-type E1 component of pyruvate dehydrogenase complex, A rho-independent terminator was present just downstream of mdeB, and open reading frames corresponding to other components of alpha-keto acid dehydrogenase complex were not found, When MdeB was overproduced in Escherichia coli, the cell extract showed the E1 activity with high specificity for alpha-ketobutyrate rather than pyruvate. These results suggest that MdeB plays an important role in the metabolism of alpha-ketobutyrate produced by MdeA from L-methionine, Accordingly, MdeB encodes a novel E1 component, alpha-ketobutyrate dehydrogenase E1 component, of an unknown alpha-keto acid dehydrogenase complex in P. putida, In addition, we found that the mdeR gene was located on the opposite strand and began at 127 bp from the translational start site of mdeA. The mdeR gene product has been identified as a member of the leucine-responsive regulatory protein (Lrp) family and revealed to act as an essential positive regulator allowing the expression of the mdeAB operon.

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