• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.483-489
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• 1998

We carried out the expression and characterization of yeast thioredoxin system including thioredexin 1 (Trx1), Trx2, thioredoxin reductase (TR), and a novel thioredoxin (Trx3), which was reported in the data base of Saccharomyces genome. The Trx1, 2 and TR were expressed as soluble proteins in E. coli and the sizes of purified proteins were equal to the reported their molecular weights. The expressed Trx3 was found in both soluble fraction and precipitate. The size of Trx3 purified from soluble fraction of E. coli crude extracts was estimated as 14 kDa on SDS-PAGE instead of 18 kDa for Trx3 in precipitate. N-terminal amino acid sequence of the small size of purified Trx3 from soluble fraction was analyzed as FQSSYTS which is correspond to the sequence from 20 to 26 for Trx3. Trx3 together with thioredoxin reductase and NADPH was able to reduce the disulfide bridge of insulin and 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB). Trx3 stimulated the antioxidant effect of thioredoxin peroxidase 1 (TPx1) which inhibited inactivation of glutamine synthetase (GS) in dithiothreitol (DTT) containing metal catalyzed oxidation system. The stimulation effect of Trx3 was 10% of the effect of either Trx1 or Trx2. In addition, Trx3 could reduce the disulfide of TPx to thiol, so that the TPx had thioredoxin dependant peroxidase activity. In western blotting analysis, antibodies against purified Trx3 did not cross-react with crude extracts of yeast, purified Trx1, and Trx2 proteins. But, in PCR reaction using the cDNA library of yeast as a template, gene encoding of trx3 was amplified.

• Journal of Life Science
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• v.32 no.1
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• pp.63-69
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• 2022

The thioredoxin reductase (TrxR) system is essential for cell survival and function by playing a pivotal role in maintaining homeostasis of cellular redox and regulating signal transduction pathways. The TrxR system comprises thioredoxin (Trx), TrxR, and nicotinamide adenine dinucleotide phosphate. Trx reduced by the catalytic reaction of the TrxR enzyme reduces downstream proteins, resulting in protection against oxidative stress and regulation of cell differentiation, growth, and death. Cancer cells survive by improving their intracellular antioxidant capacity to eliminate excessively generated reactive oxygen species (ROS) due to infinite cell proliferation and a high metabolic rate. Therefore, cancer cells have high dependence and sensitivity to antioxidant systems, suggesting that focusing on TrxR, a representative antioxidant system, is a potential strategy for cancer therapy. Several studies have revealed that TrxR is expressed at high levels in various types of cancers, and research on anticancer activity targeting the TrxR system is increasing. In this review, we discuss the feasibility and value of the TrxR system as a strategy for anticancer activity research by examining the relationship between the function of the intracellular TrxR system and the development and progression of cancer, considering the anticancer activity and mechanism of TrxR inhibitors.

• Journal of Microbiology
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• v.44 no.4
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• pp.461-465
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• 2006

The occurrence of thioredoxin reductase (NAD(P)H: oxidized-thioredoxin reductase, EC 1.6.4.5, TrxR) in five mesophilic species of Deinococcus was investigated by PAGE. Each species possessed a unique TrxR pattern, for example, a single TrxR characterized D. radiopugnans while multiple forms of TrxR occurred in other Deinococcal spp. Most of TrxRs occurring in Deinococcus showed dual cofactor specificity, active with either NADH or NADPH, although the NADPH specific-TrxR was observed in D. radiophilus and D. proteolytic us.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.1
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• pp.33-37
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• 2003

Oxidative damage to mitochondria is a critical mechanism in necrotic or apoptotic cell death induced by many kinds of toxic chemicals. Thioredoxin (Trx) family proteins are known to play protective roles in organisms under oxidative stress through redox reaction by using reducing equivalents of cysteines at a conserved active site, Cys-X-X-Cys. Whereas biological and physiological properties of Trx1 are well characterized, significance of mitochondrial thioredoxin (Trx2) is not well known. Therefore, we addressed physiological role of Trx2 in PC12 cells under oxidative stress. In PC12 cells, transiently overexpressed Trx2 significantly reduced cell death induced by hydrogen peroxide, whereas mutant Trx2, having serine residues instead of two cysteine residues at the active site did not. In addition, stably expressed Trx2 protected PC12 cells from serum deprivation. These results suggest that Trx2 may play defensive roles in PC12 cells by reducing oxidative stress to mitochondria.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.1-9
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• 2016

A unique Schizosaccharomyces pombe $TrxR^+$ gene encoding thioredoxin reductase (TrxR) was found to be positively regulated by stress-inducing agents through the stress-responsive transcription factor Pap1. In the present study, the protective roles of S. pombe TrxR were evaluated using the TrxR-overexpressing recombinant plasmid pHSM10. In the presence of hydrogen peroxide ($H_2O_2$) and superoxide anion-generating menadione (MD), S. pombe TrxR increased cellular growth and the total glutathione (GSH) level, while it reduced levels of intracellular reactive oxygen species (ROS). The nitric oxide (NO) levels of the TrxR-overexpressing cells, in the presence of $H_2O_2$ and MD, were maintained to be similar to those of the corresponding non-treated cells. Although S. pombe TrxR was able to scavenge NO generated by sodium nitroprusside (SNP), it had no significant modulating effects on cellular growth, ROS levels, or the total GSH level of SNP-exposed yeast cells, compared with the differences in those of the two non-treated cell cultures. TrxR increased the cellular growth and total GSH level, which were diminished by nitrogen starvation. It also scavenged ROS and NO produced during nitrogen starvation. Taken together, the S. pombe TrxR protects against oxidative, nitrosative, and nutritional stresses.

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.18-18
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• 2003

Thioredoxin (Trx) is a small redox protein that is ubiquitously distributed from achaes to human. In diverse organisms, the protein is involved in various physiological roles by acting as electron donor and regulators of transcription and apoptosis as well as antioxidants. Sequences of Trx within various species are 27～69% identical to that of E. coli and all Trx proteins have the same overall fold, which consists of central five β strands surrounded by four α helices. The N-terminal cysteine in WCGPC motif of Trx is redox sensitive and the motif is highly conserved. Compared with general cysteine, the N-terminal cysteine has low pKa value. The result leads to increased reduction activity of protein. Recently, novel thio.edoxin-related protein (TRP14) was found from rat brain. TRP14 acts as disulfide reductase like Trx1, and its redox potential and pKa are similar to those of Trx1. However, TRP14 takes up electrons from cytosolic thioredoxin reductase (TrxR1), not from the mitochondrial thioredoxin reductase (TrxR2). Biological roles of TES14 were reported to be involved in regulating TNF-α induced signaling pathways in different manner with Trx1. In depletion experiments, depletion of TRP14 increased TNF-α induced phosphorylation and degradation of IκBα more than the depletion Trx1 did. It also facilitated activation of JNK and p38 MAP kinase induced by TNF-α. Unlike Trx1, TRP14 shows neither interaction nor interference with ASK1. Here, we determined three-dimensional crystal structure of TRP14 by MAD method at 1.8Å. The structure reveals that the conserved cis-Pro (Pro90) and active site-W-C-X-X-C motif, which may be involved in substrate recognition similar to Trx1 , are located at the beginning position of strand β4 and helix α2, respectively. The TRP14 structure also shows that surface of TRP14 in the vicinity of the active site, which is surrounded by an extended flexible loop and an additional short a helix, is different from that of Trx1. In addition, the structure exhibits that TRP14 interact with a distinct target proteins compared with Trx1 and the binding may depend mainly on hydrophobic and charge interactions. Consequently, the structure supports biological data that the TRP14 is involved in regulating TNF-α induced signaling pathways in different manner with Trx1.

• BMB Reports
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• v.32 no.2
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• pp.168-172
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• 1999

We previously reported that a novel thiol peroxidase (p20) from Escherichia coli is a distinct periplasmic peroxidase that detoxifies hydroperoxides together with glutathione or thioredoxin. Until now, there was no experimental evidence for the presence of thioredoxin (Trx) in the periplasmic space. In an attempt to confirm the physiological function of p20 as a thiol peroxidase supported by Trx in the periplasmic space, we have purified a Trx activity from the periplasmic space of Escherichia coli and identified the Trx as the same protein as the cytoplasmic Trx. The presence of Trx in the periplasmic space of Escherichia coli suggests that p20 is a unique extracellular Trx-linked thiol peroxidase.

• Molecules and Cells
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• v.38 no.2
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• pp.187-194
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• 2015

Thioredoxin (TRX) is a disulfide reductase present ubiquitously in all taxa and plays an important role as a regulator of cellular redox state. Recently, a redox-independent, chaperone function has also been reported for some thioredoxins. We previously identified nodulin-35, the subunit of soybean uricase, as an interacting target of a cytosolic soybean thioredoxin, GmTRX. Here we report the further characterization of the interaction, which turns out to be independent of the disulfide reductase function and results in the co-localization of GmTRX and nodulin-35 in peroxisomes, suggesting a possible function of GmTRX in peroxisomes. In addition, the chaperone function of GmTRX was demonstrated in in vitro molecular chaperone activity assays including the thermal denaturation assay and malate dehydrogenase aggregation assay. Our results demonstrate that the target of GmTRX is not only confined to the nodulin-35, but many other peroxisomal proteins, including catalase (AtCAT), transthyretin-like protein 1 (AtTTL1), and acyl-coenzyme A oxidase 4 (AtACX4), also interact with the GmTRX. Together with an increased uricase activity of nodulin-35 and reduced ROS accumulation observed in the presence of GmTRX in our results, especially under heat shock and oxidative stress conditions, it appears that GmTRX represents a novel thioredoxin that is co-localized to the peroxisomes, possibly providing functional integrity to peroxisomal proteins.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.791-802
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• 2020

Theoredoxin (TRX) transgenic soybeans were developed using the human Theoredoxin gene under the control of the ��-conglycinin promoter with a selection marker, the phosphinothricin acetyltransferase (PAT) gene. This study was done to assess the acute toxicity of a genetically modified (GM) soybean using the fresh water planktonic crustacean Daphnia magna. The acute toxicity effect of the TRX soybean and non-GM soybean (Gwangan) on D. magna was investigated at different concentrations (0, 156, 313, 625, 1,250, 2,500, and 5,000 mg·L-1). The TRX soybean used for the test was confirmed to express the TRX/PAT genes by PCR and enzyme-linked immunosorbent assay (ELISA). D. magna feeding tests showed no significant differences in the cumulative immobility or an abnormal response with either the TRX soybean or non-GM soybean. The feeding study showed a similar abnormal response and cumulative immobility of the D. magna between the TRX soybean and Gwangan treatments. Additionally, the 48 h-EC50 values for the TRX and Gwangan soybeans were 755.6 and 778 mg·L-1, respectively. The soybean NOEC (no observed effect concentration) value for D. magna was suggested to be 156 mg·L-1. These results suggest that there is no significant difference in toxicity to Daphnia magna between the TRX soybean and its non-GM counterpart.

• Molecules and Cells
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• v.22 no.1
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• pp.113-118
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• 2006

Thioredoxin reductase (TrxR), a component of the redox control system involving thioredoxin (Trx), is implicated in defense against oxidative stress, control of cell growth and proliferation, and regulation of apoptosis. In the present study a stable transfectant was made by introducing the vector pcDNA3.0 harboring the fission yeast TrxR gene into COS-7 African green monkey kidney fibroblast cells. The exogenous TrxR gene led to an increase in TrxR activity of up to 3.2-fold but did not affect glutathione (GSH) content, or glutaredoxin and caspase-3 activities. Levels of reactive oxygen species (ROS), but not those of nitric oxide (NO), were reduced. Conversely, 1-chloro-2,4-dinitrobezene (CDNB), an irreversible inhibitor of mammalian TrxR, enhanced ROS levels in the COS-7 cells. After treatment with hydrogen peroxide, the level of intracellular ROS was lower in the transfectants than in the vector control cells. These results confirm that TrxR is a crucial determinant of the level of cellular ROS during oxidative stress as well as in the normal state.