scholarly journals Identification of Multiple Soluble Fe(III) Reductases in Gram-Positive Thermophilic BacteriumThermoanaerobacter indiensisBSB-33

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Subrata Pal
Keyword(s):  
Reductase Activity ◽  
Three Dimensional ◽  
Thioredoxin Reductase ◽  
Desulfovibrio Desulfuricans ◽  
Structural Similarity ◽  
Thermophilic Bacterium ◽  
Gram Positive ◽  
Reduction Activity ◽  
Structural Identity ◽  
Disulfide Reductase

Thermoanaerobacter indiensisBSB-33 has been earlier shown to reduce Fe(III) and Cr(VI) anaerobically at 60°C optimally. Further, the Gram-positive thermophilic bacterium contains Cr(VI) reduction activity in both the membrane and cytoplasm. The soluble fraction prepared fromT. indiensiscells grown at 60°C was found to contain the majority of Fe(III) reduction activity of the microorganism and produced four distinct bands in nondenaturing Fe(III) reductase activity gel. Proteins from each of these bands were partially purified by chromatography and identified by mass spectrometry (MS) with the help ofT. indiensisproteome sequences. Two paralogous dihydrolipoamide dehydrogenases (LPDs), thioredoxin reductase (Trx), NADP(H)-nitrite reductase (Ntr), and thioredoxin disulfide reductase (Tdr) were determined to be responsible for Fe(III) reductase activity. Amino acid sequence and three-dimensional (3D) structural similarity analyses of theT. indiensisFe(III) reductases were carried out with Cr(VI) reducing proteins from other bacteria. The two LPDs and Tdr showed very significant sequence and structural identity, respectively, with Cr(VI) reducing dihydrolipoamide dehydrogenase fromThermus scotoductusand thioredoxin disulfide reductase fromDesulfovibrio desulfuricans. It appears that in addition to their iron reducing activityT. indiensisLPDs and Tdr are possibly involved in Cr(VI) reduction as well.

scholarly journals Fluorogenic probes for thioredoxin reductase activity

2021 ◽  
Vol 3 ◽  
pp. 100127
Author(s):  
Tendai J. Mafireyi ◽  
Jorge O. Escobedo ◽  
Robert M. Strongin
Keyword(s):  
Reductase Activity ◽  
Thioredoxin Reductase ◽  
Fluorogenic Probes

scholarly journals Polymer cyclization for the emergence of hierarchical nanostructures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chaojian Chen ◽  
Manjesh Kumar Singh ◽  
Katrin Wunderlich ◽  
Sean Harvey ◽  
Colette J. Whitfield ◽  
...  
Keyword(s):  
Self Assembly ◽  
Three Dimensional ◽  
Hierarchical Structures ◽  
Structural Similarity ◽  
Vital Role ◽  
Nanomaterial Synthesis ◽  
Wide Range ◽  
Linear Poly ◽  
Polymer Folding ◽  
Dynamics Simulations

AbstractThe creation of synthetic polymer nanoobjects with well-defined hierarchical structures is important for a wide range of applications such as nanomaterial synthesis, catalysis, and therapeutics. Inspired by the programmability and precise three-dimensional architectures of biomolecules, here we demonstrate the strategy of fabricating controlled hierarchical structures through self-assembly of folded synthetic polymers. Linear poly(2-hydroxyethyl methacrylate) of different lengths are folded into cyclic polymers and their self-assembly into hierarchical structures is elucidated by various experimental techniques and molecular dynamics simulations. Based on their structural similarity, macrocyclic brush polymers with amphiphilic block side chains are synthesized, which can self-assemble into wormlike and higher-ordered structures. Our work points out the vital role of polymer folding in macromolecular self-assembly and establishes a versatile approach for constructing biomimetic hierarchical assemblies.

scholarly journals Mitochondrial Thioredoxin-Glutathione Reductase from LarvalTaenia crassiceps(Cysticerci)

2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
Alberto Guevara-Flores ◽  
Irene P. del Arenal ◽  
Guillermo Mendoza-Hernández ◽  
Juan Pablo Pardo ◽  
Oscar Flores-Herrera ◽  
...  
Keyword(s):  
Glutathione Reductase ◽  
Reductase Activity ◽  
Catalytic Efficiency ◽  
Dependent Manner ◽  
Exchange Reactions ◽  
Disulfide Exchange ◽  
Oxidative Inactivation ◽  
Disulfide Reductase ◽  
Thioredoxin Peroxidase ◽  
Thioredoxin Glutathione Reductase

Mitochondrial thioredoxin-glutathione reductase was purified from larvalTaenia crassiceps(cysticerci). The preparation showed NADPH-dependent reductase activity with either thioredoxin or GSSG, and was able to perform thiol/disulfide exchange reactions. At25∘Cspecific activities were437  ±  27mU mg-1and840  ±  49mU mg-1with thioredoxin and GSSG, respectively. ApparentKmvalues were0.87  ±  0.04 μM,41  ±  6 μM and19  ±  10 μM for thioredoxin, GSSG and NADPH, respectively. Thioredoxin from eukaryotic sources was accepted as substrate. The enzyme reduced H2O2in a NADPH-dependent manner, although with low catalytic efficiency. In the presence of thioredoxin, mitochondrial TGR showed a thioredoxin peroxidase-like activity. All disulfide reductase activities were inhibited by auranofin, suggesting mTGR is dependent on selenocysteine. The reductase activity with GSSG showed a higher dependence on temperature as compared with the DTNB reductase activity. The variation of the GSSG- and DTNB reductase activities on pH was dependent on the disulfide substrate. Like the cytosolic isoform, mTGR showed a hysteretic kinetic behavior at moderate or high GSSG concentrations, but it was less sensitive to calcium. The enzyme was able to protect glutamine synthetase from oxidative inactivation, suggesting that mTGR is competent to contend with oxidative stress.

A Video Super Resolution Algorithm Based on Wavelet Coefficient

2014 ◽  
Vol 610 ◽  
pp. 425-428
Author(s):  
Wei Jian Liu ◽  
Si Da Xiao ◽  
Ruo He Yao
Keyword(s):  
High Frequency ◽  
Wavelet Coefficient ◽  
Three Dimensional ◽  
Super Resolution ◽  
Structural Similarity ◽  
Image Sequences ◽  
Discrete Wavelet ◽  
Resolution Image ◽  
Resolution Algorithm ◽  
Visual Results

In this paper, we propose a new super-resolution algorithm based on wavelet coefficient. The proposed algorithm uses discrete wavelet transform (DWT) to decompose the input low-resolution image sequences into four subband images, including LL, LH, HL, HH. Then the input images have been processed by the 3DSKR (Three Dimensional Steering Kernel Regression) super resolution (SR) algorithm, and the result replaces the LL subband image, while the three high-frequency subband images have been interpolated. Finally, combining all these images to generate a new high-resolution image by using inverse DWT. Proposed method has been verified on Calendar and Foliage by Matlab software platform. The peak signal-to-noise (PSNR), structural similarity (SSIM) and visual results are compared, and show that the computational complexity of the proposed algorithm decline by 30 percent compared with the existing algorithm to obtain the approximate results.

scholarly journals Gold (III) Derivatives in Colon Cancer Treatment

2022 ◽  
Vol 23 (2) ◽  
pp. 724
Author(s):  
Agata Gurba ◽  
Przemysław Taciak ◽  
Mariusz Sacharczuk ◽  
Izabela Młynarczuk-Biały ◽  
Magdalena Bujalska-Zadrożny ◽  
...  
Keyword(s):  
Protein Structures ◽  
Thioredoxin Reductase ◽  
Structural Similarity ◽  
In Vivo Studies ◽  
Antitumor Effects ◽  
Solubility In Water ◽  
Physiological Conditions ◽  
Drug Candidates ◽  
New Methods

Cancer is one of the leading causes of morbidity and mortality worldwide. Colorectal cancer (CRC) is the third most frequently diagnosed cancer in men and the second in women. Standard patterns of antitumor therapy, including cisplatin, are ineffective due to their lack of specificity for tumor cells, development of drug resistance, and severe side effects. For this reason, new methods and strategies for CRC treatment are urgently needed. Current research includes novel platinum (Pt)- and other metal-based drugs such as gold (Au), silver (Ag), iridium (Ir), or ruthenium (Ru). Au(III) compounds are promising drug candidates for CRC treatment due to their structural similarity to Pt(II). Their advantage is their relatively good solubility in water, but their disadvantage is an unsatisfactory stability under physiological conditions. Due to these limitations, work is still underway to improve the formula of Au(III) complexes by combining with various types of ligands capable of stabilizing the Au(III) cation and preventing its reduction under physiological conditions. This review summarizes the achievements in the field of stable Au(III) complexes with potential cytotoxic activity restricted to cancer cells. Moreover, it has been shown that not nucleic acids but various protein structures such as thioredoxin reductase (TrxR) mediate the antitumor effects of Au derivatives. The state of the art of the in vivo studies so far conducted is also described.

scholarly journals Inhibition of Glutathione and Thioredoxin Metabolism Enhances Sensitivity to Perifosine in Head and Neck Cancer Cells

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Andrean L. Simons ◽  
Arlene D. Parsons ◽  
Katherine A. Foster ◽  
Kevin P. Orcutt ◽  
Melissa A. Fath ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Cancer ◽  
Reductase Activity ◽  
Thioredoxin Reductase ◽  
Buthionine Sulfoximine ◽  
Human Head ◽  
Akt Inhibitor ◽  
Simultaneous Treatment

The hypothesis that the Akt inhibitor, perifosine (PER), combined with inhibitors of glutathione (GSH) and thioredoxin (Trx) metabolism will induce cytotoxicity via metabolic oxidative stress in human head and neck cancer (HNSCC) cells was tested. PER induced increases in glutathione disulfide (%GSSG) in FaDu, Cal-27, and SCC-25 HNSCCs as well as causing significant clonogenic cell killing in FaDu and Cal-27, which was suppressed by simultaneous treatment with N-acetylcysteine (NAC). An inhibitor of GSH synthesis, buthionine sulfoximine (BSO), sensitized Cal-27 and SCC-25 cells to PER-induced clonogenic killing as well as decreased total GSH and increased %GSSG. Additionally, inhibition of thioredoxin reductase activity (TrxRed) with auranofin (AUR) was able to induce PER sensitization in SCC-25 cells that were initially refractory to PER. These results support the conclusion that PER induces oxidative stress and clonogenic killing in HNSCC cells that is enhanced with inhibitors of GSH and Trx metabolism.

scholarly journals The Archaeon Methanosarcina acetivorans Contains a Protein Disulfide Reductase with an Iron-Sulfur Cluster

2007 ◽  
Vol 189 (20) ◽  
pp. 7475-7484 ◽  
Author(s):  
Daniel J. Lessner ◽  
James G. Ferry
Keyword(s):  
Aromatic Compounds ◽  
Stress Proteins ◽  
Reductase Activity ◽  
Strictly Anaerobic ◽  
Methanosarcina Acetivorans ◽  
Gene Encoding ◽  
Iron Sulfur Cluster ◽  
Disulfide Reductase ◽  
Regulate Protein ◽  
Protein Disulfide

ABSTRACT Methanosarcina acetivorans, a strictly anaerobic methane-producing species belonging to the domain Archaea, contains a gene cluster annotated with homologs encoding oxidative stress proteins. One of the genes (MA3736) is annotated as a gene encoding an uncharacterized carboxymuconolactone decarboxylase, an enzyme required for aerobic growth with aromatic compounds by species in the domain Bacteria. Methane-producing species are not known to utilize aromatic compounds, suggesting that MA3736 is incorrectly annotated. The product of MA3736, overproduced in Escherichia coli, had protein disulfide reductase activity dependent on a C67XXC70 motif not found in carboxymuconolactone decarboxylase. We propose that MA3736 be renamed mdrA (methanosarcina disulfide reductase). Further, unlike carboxymuconolactone decarboxylase, MdrA contained an Fe-S cluster. Binding of the Fe-S cluster was dependent on essential cysteines C67 and C70, while cysteines C39 and C107 were not required. Loss of the Fe-S cluster resulted in conversion of MdrA from an inactive hexamer to a trimer with protein disulfide reductase activity. The data suggest that MdrA is the prototype of a previously unrecognized protein disulfide reductase family which contains an intermolecular Fe-S cluster that controls oligomerization as a mechanism to regulate protein disulfide reductase activity.

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