Toward a dynamic account of subject and topic : their cognitive and communicative aspects

application/pdfdepartmental bulletin pape

Transformations and sentence markedness

application/pdfdepartmental bulletin pape

Improved Search for νμ→νe Oscillation in a Long-Baseline Accelerator Experiment

journal articl

粒子法を用いた流体の気化現象シミュレーション

application/pdf三重大学大学院工学研究科博士前期課程情報工学専攻35thesi

大松山鉱山設計

東京帝国大学工科大学種別:卒業論文thesi

明末の社会関係における秩序の変動について

1979-03-31departmental bulletin pape

Structural and functional analysis of the yeast N-acetyltransferase Mpr1 involved in oxidative stress tolerance via proline metabolism

Mpr1 (sigma1278b gene for proline-analog resistance 1), which was originally isolated as N-acetyltransferase detoxifying the proline analog L-azetidine-2-carboxylate, protects yeast cells from various oxidative stresses. Mpr1 mediates the L-proline and L-arginine metabolism by acetylating L-Δ1-pyrroline-5-carboxylate, leading to the L-arginine-dependent production of nitric oxide, which confers oxidative stress tolerance. Mpr1 belongs to the Gcn5-related N-acetyltransferase (GNAT) superfamily, but exhibits poor sequence homology with the GNAT enzymes and unique substrate specificity. Here, we present the X-ray crystal structure of Mpr1 and its complex with the substrate cis-4-hydroxy-L-proline at 1.9 and 2.3 A resolution, respectively. Mpr1 is folded into α/β-structure with eight-stranded mixed β-sheets and six α-helices. The substrate binds to Asn135 and the backbone amide of Asn172 and Leu173, and the predicted acetyl-CoA-binding site is located near the backbone amide of Phe138 and the side chain of Asn178. Alanine substitution of Asn178, which can interact with the sulfur of acetyl-CoA, caused a large reduction in the apparent kcat value. The replacement of Asn135 led to a remarkable increase in the apparent Km value. These results indicate that Asn178 and Asn135 play an important role in catalysis and substrate recognition, respectively. Such a catalytic mechanism has not been reported in the GNAT proteins. Importantly, the amino acid substitutions in these residues increased the L-Δ1-pyrroline-5-carboxylate level in yeast cells exposed to heat stress, indicating that these residues are also crucial for its physiological functions. These studies provide some benefits of Mpr1 applications, such as the breeding of industrial yeasts and the development of antifungal drugs.journal articl

Effect of transformation with <i>sesC</i> and <i>sesK</i> on biofilm formation by non-biofilm-forming 8325 <i>ica</i>::<i>tet</i> mutant.

<p>Transformation of this non-biofilm-forming mutant with <i>sesC</i> restored its biofilm formation and converted it to protein-mediated biofilm-forming strain that cannot form biofilm in the presence of NaCl and is dispersed by PK but not SM. Transformation with <i>sesK</i> had no effect. Mutation of the <i>ica</i> in PIA-independent biofilm-forming BH1CC strain had no effect on its biofilm formation. (SM: sodium metaperiodate, PK: proteinase K; error bars mean standard deviation)</p

Effect of transformation with <i>sesC</i> on <i>in vitro</i> and <i>in vivo</i> catheter colonization and <i>in vivo</i> organ colonization.

<p>(<b>A</b>) Seven mm catheter fragments were inoculated with 8325–4 or its <i>sesC</i>-expressing transformant. After 2 h incubation at 37°C, catheters were rinsed and adherent bacteria were detached by sonication and the numbers of bacteria recovered from each catheter fragments were quantified by quantitative cultures. (<b>B</b>) <i>In vivo</i>, catheterized animals were inoculated through the catheter lumen with 8325–4 strain or its 8325–4 (pCN<i>sesC</i>) transformant. At day 5 post-infection, the numbers of bacteria attached to the catheters or recovered from organs were quantified by quantitative cultures. The <i>sesC</i>-expressing transformant 8325–4, (pCN<i>sesC</i>) has a higher rate of colonization of different organs up to 100-fold compare to its parental strain. *: <i>P</i><0.05</p

Effect of transformation with <i>sesC</i> on biofilm formation by the biofilm-forming isogenic <i>srtA</i> mutants of 8325–4.

<p>Effect of <i>srtA</i> mutation on biofilm formation of PIA-dependent biofilm-forming strain 8325–4, (Atl/FnBP)-mediated biofilm-forming strain BH1CC, the <i>sesC</i>-tranformed 8325–4 <i>srtA</i>::<i>tet</i> strain and complementation of 8325–4 <i>srtA</i>::<i>tet</i> (pCN<i>sesC</i>) with <i>srtA</i>, was evaluated using the quantitative microtiter plate assay. (SM: sodium metaperiodate, PK: proteinase K; error bars mean standard deviation)</p