Journal articles: 'Thioredoxin'

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Langlotz, Petra, Wolfgang Wagner, and Hartmut Follmann. "Green Algae (Scenedesmus obliquus) Contain Three Thioredoxins of Regular Size." Zeitschrift für Naturforschung C 41, no. 11-12 (December 1, 1986): 979–87. http://dx.doi.org/10.1515/znc-1986-11-1205.

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Abstract A comprehensive thioredoxin profile of Scenedesmus obliquus has been established by chromatography of heat-stable protein extracts on five different ion exchange, gel permeation, and affinity chromatography columns and using three different assay systems including homologous S. obliquus ribonucleotide reductase, chloroplast fructose-bis-phosphatase, and NADP malate dehydrogenase. Four different thioredoxins were purified to homogeneity. Besides the large chloroplast thioredoxin f described previously, the algae contain three proteins of molecular weight 12,000 designated thioredoxin I, II, and III. They bind specifically to antibodies against E. coli thioredoxin. Chloroplast-free mutant algae (strain C-2A′) lack thioredoxin f but contain all three regular thioredoxins. Species I and II have very similar amino acid composition and enzyme-stimulating activities. They are considered cytoplasmic thioredoxins which serve as hydrogen donors in algal deoxyribonucleotide biosynthesis. Thioredoxin III is of low activity towards all the presently tested enzymes and its physiological role remains unknown; its role as a glutaredoxin could be excluded. All non-photosynthetic plant cells analyzed so far (mutant algae, seeds, and roots) contain a set of three regular-size thioredoxins.

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Nikkanen, Lauri, Jouni Toivola, Manuel Guinea Diaz, and Eevi Rintamäki. "Chloroplast thioredoxin systems: prospects for improving photosynthesis." Philosophical Transactions of the Royal Society B: Biological Sciences 372, no. 1730 (August 14, 2017): 20160474. http://dx.doi.org/10.1098/rstb.2016.0474.

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Thioredoxins (TRXs) are protein oxidoreductases that control the structure and function of cellular proteins by cleavage of a disulphide bond between the side chains of two cysteine residues. Oxidized thioredoxins are reactivated by thioredoxin reductases (TR) and a TR-dependent reduction of TRXs is called a thioredoxin system. Thiol-based redox regulation is an especially important mechanism to control chloroplast proteins involved in biogenesis, in regulation of light harvesting and distribution of light energy between photosystems, in photosynthetic carbon fixation and other biosynthetic pathways, and in stress responses of plants. Of the two plant plastid thioredoxin systems, the ferredoxin-dependent system relays reducing equivalents from photosystem I via ferredoxin and ferredoxin-thioredoxin reductase (FTR) to chloroplast proteins, while NADPH-dependent thioredoxin reductase (NTRC) forms a complete thioredoxin system including both reductase and thioredoxin domains in a single polypeptide. Chloroplast thioredoxins transmit environmental light signals to biochemical reactions, which allows fine tuning of photosynthetic processes in response to changing environmental conditions. In this paper we focus on the recent reports on specificity and networking of chloroplast thioredoxin systems and evaluate the prospect of improving photosynthetic performance by modifying the activity of thiol regulators in plants.This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement'.

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Nikkanen, Lauri, and Eevi Rintamäki. "Thioredoxin-dependent regulatory networks in chloroplasts under fluctuating light conditions." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1640 (April 19, 2014): 20130224. http://dx.doi.org/10.1098/rstb.2013.0224.

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Plants have adopted a number of mechanisms to restore redox homeostasis in the chloroplast under fluctuating light conditions in nature. Chloroplast thioredoxin systems are crucial components of this redox network, mediating environmental signals to chloroplast proteins. In the reduced state, thioredoxins control the structure and function of proteins by reducing disulfide bridges in the redox active site of a protein. Subsequently, an oxidized thioredoxin is reduced by a thioredoxin reductase, the two enzymes together forming a thioredoxin system. Plant chloroplasts have versatile thioredoxin systems, including two reductases dependent on ferredoxin and NADPH as reducing power, respectively, several types of thioredoxins, and the system to deliver thiol redox signals to the thylakoid membrane and lumen. Light controls the activity of chloroplast thioredoxin systems in two ways. First, light reactions activate the thioredoxin systems via donation of electrons to oxidized ferredoxin and NADP + , and second, light induces production of reactive oxygen species in chloroplasts which deactivate the components of the thiol redox network. The diversity and partial redundancy of chloroplast thioredoxin systems enable chloroplast metabolism to rapidly respond to ever-changing environmental conditions and to raise plant fitness in natural growth conditions.

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Cadet, F., and J. C. Meunier. "Spinach (Spinacia oleracea) chloroplast sedoheptulose-1,7-bisphosphatase. Activation and deactivation, and immunological relationship to fructose-1,6-bisphosphatase." Biochemical Journal 253, no. 1 (July 1, 1988): 243–48. http://dx.doi.org/10.1042/bj2530243.

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In this paper we study activation by dithiothreitol and reduced thioredoxins and deactivation by oxidized thioredoxins f of sedoheptulose-1,7-bisphosphatase. The behaviour of the enzyme when chromatographed on a thioredoxin-Sepharose column is also described. The enzyme is autoxidizable upon removal of reducing agents, and is activated when reduced by any of the thioredoxins. This mechanism may allow the regulation of the Calvin cycle upon light-dark and dark-light transitions. The formation of a stable complex between enzyme and thioredoxin could explain the inhibitory effect of high thioredoxin concentrations. The use of immunological techniques shows that sedoheptulose-1,7-bisphosphatase and fructose-1,6-bisphosphatase are poorly related immunologically.

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SERRATO, Antonio J., Juan M. PÉREZ-RUIZ, and Francisco J. CEJUDO. "Cloning of thioredoxin h reductase and characterization of the thioredoxin reductase–thioredoxin h system from wheat." Biochemical Journal 367, no. 2 (October 15, 2002): 491–97. http://dx.doi.org/10.1042/bj20020103.

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Thioredoxins h are ubiquitous proteins reduced by NADPH— thioredoxin reductase (NTR). They are able to reduce disulphides in target proteins. In monocots, thioredoxins h accumulate at high level in seeds and show a predominant localization in the nucleus of seed cells. These results suggest that the NTR—thioredoxin h system probably plays an important role in seed physiology. To date, the study of this system in monocots is limited by the lack of information about NTR. In the present study, we describe the cloning of a full-length cDNA encoding NTR from wheat (Triticum aestivum). The polypeptide deduced from this cDNA shows close similarity to NTRs from Arabidopsis, contains FAD- and NADPH-binding domains and a disulphide probably interacting with the disulphide at the active site of thioredoxin h. Wheat NTR was expressed in Escherichia coli as a His-tagged protein. The absorption spectrum of the purified recombinant protein is typical of flavoenzymes. Furthermore, it showed NADPH-dependent thioredoxin h reduction activity, thus confirming that the cDNA clone reported in the present study encodes wheat NTR. Using the His-tagged NTR and TRXhA (wheat thioredoxin h), we successfully reconstituted the wheat NTR—thioredoxin h system in vitro, as shown by the insulin reduction assay. A polyclonal antibody was raised against wheat NTR after immunization of rabbits with the purified His-tagged protein. This antibody efficiently detected a single polypeptide of the corresponding molecular mass in seed extracts and it allowed the analysis of the pattern of accumulation of NTR in different wheat organs and developmental stages. NTR shows a wide distribution in wheat, but, surprisingly, its accumulation in seeds is low, in contrast with the level of thioredoxins h.

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6

Langlotz, Petra, Wolfgang Wagner, and Hartmut Follmann. "A Large Chloroplast Thioredoxin ƒ Found in Green Algae." Zeitschrift für Naturforschung C 41, no. 3 (March 1, 1986): 275–83. http://dx.doi.org/10.1515/znc-1986-0306.

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Unicellular green algae differ from plant leaves in their thioredoxin profile. Besides several thioredoxins of regular size (Mr = 12,000), the heat-stable protein fraction of extracts from Scenedesmus obliquus cells contains a large protein of molecular weight Mr - 28,000 which is designated thioredoxin ƒ on the basis of typical properties, in particular by its capacity to stimulate spinach chloroplast fructose-bis-phosphatase and, to lower degree, E. coli ribonucleotide reductase. The new thioredoxin was purified to apparent homogeneity by chromatography on DEAE cellulose, Sephadex G-50. CM cellulose, and Blue Sepharose. When tested in homologous enzyme systems, reduced thioredoxin ƒ strongly activated algal fructose-bis-phosphatase, but was inactive towards the cytoplasmic algal ribonucleotide reductase; NADP malate dehydrogenase was also stimulated. The protein is missing in extracts from a chloroplast-free mutant strain, C-2A′, but appears together with other chloroplast components upon illumination. Protein ƒ is therefore the main chloroplast thioredoxin of the green algae, probably corresponding to the smaller leaf chloroplast thioredoxins ƒ and m combined. Algal thioredoxin ƒ appears closely related, however, to the large thioredoxin found in a cyanobacterium, Anabaena sp.

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Bodenstein, Johanna, and Hartmut Follmann. "Characterization of Two Thioredoxins in Pig Heart Including a New Mitochondrial Protein." Zeitschrift für Naturforschung C 46, no. 3-4 (April 1, 1991): 270–79. http://dx.doi.org/10.1515/znc-1991-3-418.

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Heart tissue contains two different thioredoxins. One is a specific mitochondrial protein and is best prepared from pre-isolated, intact heart mitochondria (mt-thioredoxin) whereas mitochondria-depleted tissue homogenates contain the major cellular thioredoxin of cytoplasmic origin (c-thioredoxin). Both heat-stable proteins are clearly differentiated chrom atographically. They exhibit slightly different molecular weights (12300 vs. 12000) and isoelectric points (4.7 vs. 4.8) but differ remarkably in their cysteine content: mt-Thioredoxin has two cysteine residues like the bacterial proteins, and c-thioredoxin possesses six cysteines. Heart extracts were also show n to contain a NADPH-specific thioredoxin reductase of the known mammalian type. A specific function or target enzyme of mt-thioredoxin has not as yet been established.

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Berndt, Carsten, Christopher Horst Lillig, and Arne Holmgren. "Thiol-based mechanisms of the thioredoxin and glutaredoxin systems: implications for diseases in the cardiovascular system." American Journal of Physiology-Heart and Circulatory Physiology 292, no. 3 (March 2007): H1227—H1236. http://dx.doi.org/10.1152/ajpheart.01162.2006.

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Reactive oxygen species (ROS) and the cellular thiol redox state are crucial mediators of multiple cell processes like growth, differentiation, and apoptosis. Excessive ROS production or oxidative stress is associated with several diseases, including cardiovascular disorders like ischemia-reperfusion. To prevent ROS-induced disorders, the heart is equipped with effective antioxidant systems. Key players in defense against oxidative stress are members of the thioredoxin-fold family of proteins. Of these, thioredoxins and glutaredoxins maintain a reduced intracellular redox state in mammalian cells by the reduction of protein thiols. The reversible oxidation of Cys-Gly-Pro-Cys or Cys-Pro(Ser)-Tyr-Cys active site cysteine residues is used in reversible electron transport. Thioredoxins and glutaredoxins belong to corresponding systems consisting of NADPH, thioredoxin reductase, and thioredoxin or NADPH, glutathione reductase, glutathione, and glutaredoxin, respectively. Thioredoxin as well as glutaredoxin activities appear to be very important for the progression and severity of several cardiovascular disorders. These proteins function not only as antioxidants, they inhibit or activate apoptotic signaling molecules like apoptosis signal-regulating kinase 1 and Ras or transcription factors like NF-κB. Thioredoxin activity is regulated by the endogenous inhibitor thioredoxin-binding protein 2 (TBP-2), indicating an important role of the balance between thioredoxin and TBP-2 levels in cardiovascular diseases. In this review, we will summarize cardioprotective effects of endogenous thioredoxin and glutaredoxin systems as well as the high potential in clinical applications of exogenously applied thioredoxin or glutaredoxin or the induction of endogenous thioredoxin and glutaredoxin systems.

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9

Léveillard, Thierry, and Najate Aït-Ali. "Cell Signaling with Extracellular Thioredoxin and Thioredoxin-Like Proteins: Insight into Their Mechanisms of Action." Oxidative Medicine and Cellular Longevity 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/8475125.

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Thioredoxins are small thiol-oxidoreductase enzymes that control cellular redox homeostasis. Paradoxically, human thioredoxin (TXN1) was first identified as the adult T cell leukemia-derived factor (ADF), a secreted protein. ADF has been implicated in a wide variety of cell-to-cell communication systems acting as a cytokine or a chemokine. TRX80 is a truncated TXN1 protein with cytokine activity. The unconventional secretion mechanism of these extracellular thioredoxins is unknown. The thioredoxin system is relying on glucose metabolism through the pentose phosphate pathway that provides reducing power in the form of NADPH, the cofactor of thioredoxin reductase (TXNRD). While a complete extracellular TXN system is present in the blood in the form of circulating TXN1 and TXNDR1, the source of extracellular NADPH remains a mystery. In the absence of redox regenerating capacity, extracellular thioredoxins may rather be prooxidant agents. Rod-derived cone viability factor (RdCVF) is the product of intron retention of the nucleoredoxin-like 1 (NXNL1) gene, a secreted truncated thioredoxin-like protein. The other product encoded by the gene, RdCVFL, is an enzymatically active thioredoxin. This is a very singular example of positive feedback of a superthioredoxin system encoded by a single gene likely emerging during evolution from metabolic constraints on redox signaling.

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10

Langlotz, Petra, and Hartmut Follmann. "Notes: Formation of Large Thioredoxin f Accompanies Chloroplast Development in Scenedesmus obliquus." Zeitschrift für Naturforschung C 42, no. 11-12 (December 1, 1987): 1364–66. http://dx.doi.org/10.1515/znc-1987-11-1241.

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Chloroplast-free mutant cells C-2A′ of the green algae Scenedesmus obliquus lack thioredoxin f, which functions in the light activation of chloroplast enzymes, but do contain the regular thioredoxins I and II. When dark-grown algae are transferred to light, thioredoxin f activity appears rapidly and increases in parallel with photosynthetic activities: however it precedes chlorophyll biosynthesis. The formation of thioredoxin f is inhibited by cydoheximide indicating that it occurs on the cytoplasmic ribosomes, in accord with the lack of thioredoxin genes on the chloroplast genomes.

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Rohrbach, Susanne, Stefanie Gruenler, Mirja Teschner, and Juergen Holtz. "The thioredoxin system in aging muscle: key role of mitochondrial thioredoxin reductase in the protective effects of caloric restriction?" American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 291, no. 4 (October 2006): R927—R935. http://dx.doi.org/10.1152/ajpregu.00890.2005.

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Cellular redox balance is maintained by various antioxidative systems. Among those is the thioredoxin system, consisting of thioredoxin, thioredoxin reductase, and NADPH. In the present study, we examined the effects of caloric restriction (2 mo) on the expression of the cytosolic and mitochondrial thioredoxin system in skeletal muscle and heart of senescent and young rats. Mitochondrial thioredoxin reductase (TrxR2) is significantly reduced in aging skeletal and cardiac muscle and renormalized after caloric restriction, while the cytosolic isoform remains unchanged. Thioredoxins (mitochondrial Trx2, cytosolic Trx1) are not influenced by caloric restriction. In skeletal and cardiac muscle of young rats, caloric restriction has no effect on the expression of thioredoxins or thioredoxin reductases. Enforced reduction of TrxR2 (small interfering RNA) in myoblasts under exposure to ceramide or TNF-α causes a dramatic enhancement of nucleosomal DNA cleavage, caspase 9 activation, and mitochondrial reactive oxygen species release, together with reduced cell viability, while this TrxR2 reduction is without effect in unstimulated myoblasts under basal conditions. Oxidative stress in vitro (H2O2in C2C12myoblasts and myotubes) results in different changes: TrxR2, Trx2, and Trx1 are induced without alterations in the cytosolic thioredoxin reductase isoforms. Thus aging is associated with a TrxR2 reduction in skeletal muscle and heart, which enhances susceptibility to apoptotic stimuli but is renormalized after short-term caloric restriction. Exogenous oxidative stress does not result in these age-related changes of TrxR2.

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Akif, Mohd, Garima Khare, Anil K. Tyagi, Shekhar C. Mande, and Abhijit A. Sardesai. "Functional Studies of Multiple Thioredoxins from Mycobacterium tuberculosis." Journal of Bacteriology 190, no. 21 (August 22, 2008): 7087–95. http://dx.doi.org/10.1128/jb.00159-08.

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ABSTRACT Cytoplasmic protein reduction via generalized thiol/disulfide exchange reactions and maintenance of cellular redox homeostasis is mediated by the thioredoxin superfamily of proteins. Here, we describe the characterization of the thioredoxin system from Mycobacterium tuberculosis, whose genome bears the potential to encode three putative thioredoxins from the open reading frames designated trxAMtb , trxBMtb , and trxCMtb . We show that all three thioredoxins, overproduced in Escherichia coli, are able to reduce insulin, a model substrate, in the presence of dithiothreitol. However, we observe that thioredoxin reductase is not capable of reducing TrxA Mtb in an NADPH-dependent manner, indicating that only TrxB Mtb and TrxC Mtb are the biologically active disulfide reductases. The absence of detectable mRNA transcripts of trxAMtb observed when M. tuberculosis strain H37Rv was cultivated under different growth conditions suggests that trxAMtb expression may be cryptic. The measured redox potentials of TrxB Mtb and TrxC Mtb (−262 ± 2 mV and −269 ± 2 mV, respectively) render these proteins somewhat more oxidizing than E. coli thioredoxin 1 (TrxA). In E. coli strains lacking components of cytoplasmic protein reduction pathways, heterologous expression of the mycobacterial thioredoxins was able to effectively substitute for their function.

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Lunn, JE, A. Agostino, and MD Hatch. "Regulation of NADP-Malate Dehydrogenase in C4 Plants: Activity and Properties of Maize Thioredoxin M and the Significance of Non-Active Site Thiol Groups." Functional Plant Biology 22, no. 4 (1995): 577. http://dx.doi.org/10.1071/pp9950577.

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Some unusual properties of purified maize leaf thioredoxin m were attributable to the presence of non-active site thiol groups, Unlike thioredoxins from other sources, maize leaf thioredoxin m was susceptible to inactivation by heating and this was associated with polymerisation of the molecule. Both these effects of heating were prevented or reversed by adding thiol compounds such as dithiothreitol. We concluded that, on heating, the free SH groups in the oxidised thioredoxin m molecule react with disulfide groups of other molecules to form polymeric complexes linked by disulfide bonds. We also observed the formation of a stable complex between the oxidised forms of thioredoxin m and NADP-malate dehydrogenase (NADP-MDH) under certain conditions. Evidence that in maize chloroplasts thioredoxin m and NADP-MDH occur in a 1: 1 molar ratio suggested that they may exist as a complex in vivo. However, ratios of thioredoxin rn to NADP-MDH varied widely in other species but always with thioredoxin m in excess. Furthermore, the complex we observed in vitro was shown to be the result of intermolecular disulfide bond formation and apparently occurred only with a non-physiological form of oxidised thioredoxin m. We could not demonstrate any non-covalent binding between thioredoxin m and NADP-MDH.

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Smits, Wiep Klaas, Jean-Yves F. Dubois, Sierd Bron, Jan Maarten van Dijl, and Oscar P. Kuipers. "Tricksy Business: Transcriptome Analysis Reveals the Involvement of Thioredoxin A in Redox Homeostasis, Oxidative Stress, Sulfur Metabolism, and Cellular Differentiation in Bacillus subtilis." Journal of Bacteriology 187, no. 12 (June 15, 2005): 3921–30. http://dx.doi.org/10.1128/jb.187.12.3921-3930.2005.

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ABSTRACT Thioredoxins are important thiol-reactive proteins. Most knowledge about this class of proteins is derived from proteome studies, and little is known about the global transcriptional response of cells to various thioredoxin levels. In Bacillus subtilis, thioredoxin A is encoded by trxA and is essential for viability. In this study, we report the effects of minimal induction of a strain carrying an IPTG (isopropyl-β-d-thiogalactopyranoside)-inducible trxA gene (ItrxA) on transcription levels, as determined by DNA macroarrays. The effective depletion of thioredoxin A leads to the induction of genes involved in the oxidative stress response (but not those dependent on PerR), phage-related functions, and sulfur utilization. Also, several stationary-phase processes, such as sporulation and competence, are affected. The majority of these phenotypes are rescued by a higher induction level of ItrxA, leading to an approximately wild-type level of thioredoxin A protein. A comparison with other studies shows that the effects of thioredoxin depletion are distinct from, but show some similarity to, oxidative stress and disulfide stress. Some of the transcriptional effects may be linked to thioredoxin-interacting proteins. Finally, thioredoxin-linked processes appear to be conserved between prokaryotes and eukaryotes.

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Gamiz-Arco, Gloria, Valeria A. Risso, Adela M. Candel, Alvaro Inglés-Prieto, Maria L. Romero-Romero, Eric A. Gaucher, Jose A. Gavira, Beatriz Ibarra-Molero, and Jose M. Sanchez-Ruiz. "Non-conservation of folding rates in the thioredoxin family reveals degradation of ancestral unassisted-folding." Biochemical Journal 476, no. 23 (December 10, 2019): 3631–47. http://dx.doi.org/10.1042/bcj20190739.

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Evolution involves not only adaptation, but also the degradation of superfluous features. Many examples of degradation at the morphological level are known (vestigial organs, for instance). However, the impact of degradation on molecular evolution has been rarely addressed. Thioredoxins serve as general oxidoreductases in all cells. Here, we report extensive mutational analyses on the folding of modern and resurrected ancestral bacterial thioredoxins. Contrary to claims from recent literature, in vitro folding rates in the thioredoxin family are not evolutionarily conserved, but span at least a ∼100-fold range. Furthermore, modern thioredoxin folding is often substantially slower than ancestral thioredoxin folding. Unassisted folding, as probed in vitro, thus emerges as an ancestral vestigial feature that underwent degradation, plausibly upon the evolutionary emergence of efficient cellular folding assistance. More generally, our results provide evidence that degradation of ancestral features shapes, not only morphological evolution, but also the evolution of individual proteins.

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Trotter, Eleanor W., and Chris M. Grant. "Overlapping Roles of the Cytoplasmic and Mitochondrial Redox Regulatory Systems in the Yeast Saccharomyces cerevisiae." Eukaryotic Cell 4, no. 2 (February 2005): 392–400. http://dx.doi.org/10.1128/ec.4.2.392-400.2005.

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ABSTRACT Thioredoxins are small, highly conserved oxidoreductases which are required to maintain the redox homeostasis of the cell. Saccharomyces cerevisiae contains a cytoplasmic thioredoxin system (TRX1, TRX2, and TRR1) as well as a complete mitochondrial thioredoxin system, comprising a thioredoxin (TRX3) and a thioredoxin reductase (TRR2). In the present study we have analyzed the functional overlap between the two systems. By constructing mutant strains with deletions of both the mitochondrial and cytoplasmic systems (trr1 trr2 and trx1 trx2 trx3), we show that cells can survive in the absence of both systems. Analysis of the redox state of the cytoplasmic thioredoxins reveals that they are maintained independently of the mitochondrial system. Similarly, analysis of the redox state of Trx3 reveals that it is maintained in the reduced form in wild-type cells and in mutants lacking components of the cytoplasmic thioredoxin system (trx1 trx2 or trr1). Surprisingly, the redox state of Trx3 is also unaffected by the loss of the mitochondrial thioredoxin reductase (trr2) and is largely maintained in the reduced form unless cells are exposed to an oxidative stress. Since glutathione reductase (Glr1) has been shown to colocalize to the cytoplasm and mitochondria, we examined whether loss of GLR1 influences the redox state of Trx3. During normal growth conditions, deletion of TRR2 and GLR1 was found to result in partial oxidation of Trx3, indicating that both Trr2 and Glr1 are required to maintain the redox state of Trx3. The oxidation of Trx3 in this double mutant is even more pronounced during oxidative stress or respiratory growth conditions. Taken together, these data indicate that Glr1 and Trr2 have an overlapping function in the mitochondria.

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Viefhues, Anne, Jens Heller, Nora Temme, and Paul Tudzynski. "Redox Systems in Botrytis cinerea: Impact on Development and Virulence." Molecular Plant-Microbe Interactions® 27, no. 8 (August 2014): 858–74. http://dx.doi.org/10.1094/mpmi-01-14-0012-r.

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The thioredoxin system is of great importance for maintenance of cellular redox homeostasis. Here, we show that it has a severe influence on virulence of Botrytis cinerea, demonstrating that redox processes are important for host-pathogen interactions in this necrotrophic plant pathogen. The thioredoxin system is composed of two enzymes, the thioredoxin and the thioredoxin reductase. We identified two genes encoding for thioredoxins (bctrx1, bctrx2) and one gene encoding for a thioredoxin reductase (bctrr1) in the genome of B. cinerea. Knockout mutants of bctrx1 and bctrr1 were severely impaired in virulence and more sensitive to oxidative stress. Additionally, Δbctrr1 showed enhanced H2O2 production and retarded growth. To investigate the impact of the second major cellular redox system, glutathione, we generated deletion mutants for two glutathione reductase genes. The effects were only marginal; deletion of bcglr1 resulted in reduced germination and, correspondingly, to retarded infection as well as reduced growth on minimal medium, whereas bcglr2 deletion had no distinctive phenotype. In summary, we showed that the balanced redox status maintained by the thioredoxin system is essential for development and pathogenesis of B. cinerea, whereas the second major cellular redox system, the glutathione system, seems to have only minor impact on these processes.

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Seco-Cervera, Marta, Pilar González-Cabo, Federico Pallardó, Carlos Romá-Mateo, and José García-Giménez. "Thioredoxin and Glutaredoxin Systems as Potential Targets for the Development of New Treatments in Friedreich’s Ataxia." Antioxidants 9, no. 12 (December 10, 2020): 1257. http://dx.doi.org/10.3390/antiox9121257.

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The thioredoxin family consists of a small group of redox proteins present in all organisms and composed of thioredoxins (TRXs), glutaredoxins (GLRXs) and peroxiredoxins (PRDXs) which are found in the extracellular fluid, the cytoplasm, the mitochondria and in the nucleus with functions that include antioxidation, signaling and transcriptional control, among others. The importance of thioredoxin family proteins in neurodegenerative diseases is gaining relevance because some of these proteins have demonstrated an important role in the central nervous system by mediating neuroprotection against oxidative stress, contributing to mitochondrial function and regulating gene expression. Specifically, in the context of Friedreich’s ataxia (FRDA), thioredoxin family proteins may have a special role in the regulation of Nrf2 expression and function, in Fe-S cluster metabolism, controlling the expression of genes located at the iron-response element (IRE) and probably regulating ferroptosis. Therefore, comprehension of the mechanisms that closely link thioredoxin family proteins with cellular processes affected in FRDA will serve as a cornerstone to design improved therapeutic strategies.

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Jakupoglu, Cemile, Gerhard K. H. Przemeck, Manuela Schneider, Stéphanie G. Moreno, Nadja Mayr, Antonis K. Hatzopoulos, Martin Hrabé de Angelis, et al. "Cytoplasmic Thioredoxin Reductase Is Essential for Embryogenesis but Dispensable for Cardiac Development." Molecular and Cellular Biology 25, no. 5 (March 1, 2005): 1980–88. http://dx.doi.org/10.1128/mcb.25.5.1980-1988.2005.

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ABSTRACT Two distinct thioredoxin/thioredoxin reductase systems are present in the cytosol and the mitochondria of mammalian cells. Thioredoxins (Txn), the main substrates of thioredoxin reductases (Txnrd), are involved in numerous physiological processes, including cell-cell communication, redox metabolism, proliferation, and apoptosis. To investigate the individual contribution of mitochondrial (Txnrd2) and cytoplasmic (Txnrd1) thioredoxin reductases in vivo, we generated a mouse strain with a conditionally targeted deletion of Txnrd1. We show here that the ubiquitous Cre-mediated inactivation of Txnrd1 leads to early embryonic lethality. Homozygous mutant embryos display severe growth retardation and fail to turn. In accordance with the observed growth impairment in vivo, Txnrd1-deficient embryonic fibroblasts do not proliferate in vitro. In contrast, ex vivo-cultured embryonic Txnrd1-deficient cardiomyocytes are not affected, and mice with a heart-specific inactivation of Txnrd1 develop normally and appear healthy. Our results indicate that Txnrd1 plays an essential role during embryogenesis in most developing tissues except the heart.

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Sytykiewicz, Hubert, Iwona Łukasik, Sylwia Goławska, Iwona Sprawka, Artur Goławski, Julia Sławianowska, and Katarzyna Kmieć. "Expression of Thioredoxin/Thioredoxin Reductase System Genes in Aphid-Challenged Maize Seedlings." International Journal of Molecular Sciences 21, no. 17 (August 31, 2020): 6296. http://dx.doi.org/10.3390/ijms21176296.

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Thioredoxins (Trxs) and thioredoxin reductases (TrxRs) encompass a highly complex network involved in sustaining thiol-based redox homeostasis in plant tissues. The purpose of the study was to gain a new insight into transcriptional reprogramming of the several genes involved in functioning of Trx/TrxR system in maize (Zea mays L.) seedlings, exposed to the bird cherry-oat aphid (Rhopalosiphum padi L.) or the rose-grass aphid (Metopolophium dirhodum Walk.) infestation. The biotests were performed on two maize genotypes (susceptible Złota Karłowa and relatively resistant Waza). The application of real-time qRT-PCR technique allowed to identify a molecular mechanism triggered in more resistant maize plants, linked to upregulation of thioredoxins-encoding genes (Trx-f, Trx-h, Trx-m, Trx-x) and thioredoxin reductase genes (Ftr1, Trxr2). Significant enhancement of TrxR activity in aphid-infested Waza seedlings was also demonstrated. Furthermore, we used an electrical penetration graph (EPG) recordings of M. dirhodum stylet activities in seedlings of the two studied maize varieties. Duration of phloem phase (E1 and E2 models) of rose-grass aphids was about three times longer while feeding in Waza plants, compared to Złota Karłowa cv. The role of activation of Trx/TrxR system in maintaining redox balance and counteracting oxidative-induced damages of macromolecules in aphid-stressed maize plants is discussed.

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Buey, Rubén M., David Fernández-Justel, Gloria González-Holgado, Marta Martínez-Júlvez, Adrián González-López, Adrián Velázquez-Campoy, Milagros Medina, Bob B. Buchanan, and Monica Balsera. "Unexpected diversity of ferredoxin-dependent thioredoxin reductases in cyanobacteria." Plant Physiology 186, no. 1 (February 18, 2021): 285–96. http://dx.doi.org/10.1093/plphys/kiab072.

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Abstract Thioredoxin reductases control the redox state of thioredoxins (Trxs)—ubiquitous proteins that regulate a spectrum of enzymes by dithiol–disulfide exchange reactions. In most organisms, Trx is reduced by NADPH via a thioredoxin reductase flavoenzyme (NTR), but in oxygenic photosynthetic organisms, this function can also be performed by an iron-sulfur ferredoxin (Fdx)-dependent thioredoxin reductase (FTR) that links light to metabolic regulation. We have recently found that some cyanobacteria, such as the thylakoid-less Gloeobacter and the ocean-dwelling green oxyphotobacterium Prochlorococcus, lack NTR and FTR but contain a thioredoxin reductase flavoenzyme (formerly tentatively called deeply-rooted thioredoxin reductase or DTR), whose electron donor remained undefined. Here, we demonstrate that Fdx functions in this capacity and report the crystallographic structure of the transient complex between the plant-type Fdx1 and the thioredoxin reductase flavoenzyme from Gloeobacter violaceus. Thereby, our data demonstrate that this cyanobacterial enzyme belongs to the Fdx flavin-thioredoxin reductase (FFTR) family, originally described in the anaerobic bacterium Clostridium pasteurianum. Accordingly, the enzyme hitherto termed DTR is renamed FFTR. Our experiments further show that the redox-sensitive peptide CP12 is modulated in vitro by the FFTR/Trx system, demonstrating that FFTR functionally substitutes for FTR in light-linked enzyme regulation in Gloeobacter. Altogether, we demonstrate the FFTR is spread within the cyanobacteria phylum and propose that, by substituting for FTR, it connects the reduction of target proteins to photosynthesis. Besides, the results indicate that FFTR acquisition constitutes a mechanism of evolutionary adaptation in marine phytoplankton such as Prochlorococcus that live in low-iron environments.

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Lee, Hang-mao, Karl Josef Dietz, and Ralf Hofestädt. "Prediction of thioredoxin and glutaredoxin target proteins by identifying reversibly oxidized cysteinyl residues." Journal of Integrative Bioinformatics 7, no. 3 (December 1, 2010): 208–18. http://dx.doi.org/10.1515/jib-2010-130.

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Summary A significant part of cellular proteins undergo reversible thiol-dependent redox transitions which often control or switch protein functions. Thioredoxins and glutaredoxins constitute two key players in this redox regulatory protein network. Both interact with various categories of proteins containing reversibly oxidized cysteinyl residues. The identification of thioredoxin/glutaredoxin target proteins is a critical step in constructing the redox regulatory network of cells or subcellular compartments. Due to the scarcity of thioredoxin/glutaredoxin target protein records in the public database, a tool called Reversibly Oxidized Cysteine Detector (ROCD) is implemented here to identify potential thioredoxin/glutaredoxin target proteins computationally, so that the in silico construction of redox regulatory network may become feasible. ROCD was tested on 46 thioredoxin target proteins in plant mitochondrion, and the recall rate was 66.7% when 50% sequence identity was chosen for structural model selection. ROCD will be used to predict the thioredoxin/glutaredoxin target proteins in human liver mitochondrion for our redox regulatory network construction project. The ROCD will be developed further to provide prediction with more reliability and incorporated into biological network visualization tools as a node prediction component. This work will advance the capability of traditional database- or text mining-based method in the network construction.

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Achard, Maud E. S., Amanda J. Hamilton, Tarek Dankowski, Begoña Heras, Mark S. Schembri, Jennifer L. Edwards, Michael P. Jennings, and Alastair G. McEwan. "A Periplasmic Thioredoxin-Like Protein Plays a Role in Defense against Oxidative Stress in Neisseria gonorrhoeae." Infection and Immunity 77, no. 11 (August 17, 2009): 4934–39. http://dx.doi.org/10.1128/iai.00714-09.

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ABSTRACT Thioredoxin-like proteins of the TlpA/ResE/CcmG subfamily are known to face the periplasm in gram-negative bacteria. Using the tlpA gene of Bradyrhizobium japonicum as a query, we identified a locus (NGO1923) in Neisseria gonorrhoeae that encodes a thioredoxin-like protein (NG_TlpA). Bioinformatics analysis indicated that the predicted NG_TlpA protein contained a cleavable signal peptide at the N terminus, and secondary structure analysis identified a thioredoxin fold with a helical insertion (∼25 residues), similar to that found in B. japonicum TlpA but absent in cytoplasmic thioredoxins. Biochemical characterization of a recombinant form of NG_TlpA revealed a standard redox potential (E0′) of −206 mV. This property and the observation that the oxidized form of the protein exhibited greater thermal stability than the reduced species indicated that NG_TlpA is a reducing thioredoxin and not an oxidizing thiol-disulfide oxidoreductase like DsbA. The thioredoxin activity of NG_TlpA was confirmed in an insulin disulfide reduction assay. A tlpA mutant of N. gonorrhoeae strain 1291 was found to be highly sensitive to oxidative killing by paraquat and hydrogen peroxide, indicating an antioxidant role for the NG_TlpA in this bacterium. The tlpA mutant also exhibited reduced intracellular survival in human primary cervical epithelial cells.

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Henderson, Brian, Peter Tabona, Stephen Poole, and Sean P. Nair. "Cloning and Expression of the Actinobacillus actinomycetemcomitans Thioredoxin (trx) Gene and Assessment of Cytokine Inhibitory Activity." Infection and Immunity 69, no. 1 (January 1, 2001): 154–58. http://dx.doi.org/10.1128/iai.69.1.154-158.2001.

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ABSTRACT Thioredoxin is a ubiquitous redox control and cell stress protein. Unexpectedly, in recent years, thioredoxins have been found to exhibit both cytokine and chemokine activities, and there is increasing evidence that this class of protein plays a role in the pathogenesis of inflammatory diseases. In spite of this evidence, it has been reported that the oral bacterium and periodontopathogen Actinobacillus actinomycetemcomitans secretes an immunosuppressive factor (termed suppressive factor 1 [SF1] [T. Kurita-Ochiai and K. Ochiai, Infect. Immun. 64:50–54, 1996]) whose N-terminal sequence, we have determined, identifies it as thioredoxin. We have cloned and expressed the gene encoding the thioredoxin of A. actinomycetemcomitans and have purified the protein to homogeneity. The A. actinomycetemcomitans trx gene has 52 and 76% identities, respectively, to the trx genes ofEscherichia coli and Haemophilus influenzae. Enzymatic analysis revealed that the recombinant protein had the expected redox activity. When the recombinant thioredoxin was tested for its capacity to inhibit the production of cytokines by human peripheral blood mononuclear cells, it showed no significant inhibitory capacity. We therefore conclude that the thioredoxin of A. actinomycetemcomitans does not act as an immunosuppressive factor, at least with human leukocytes in cultures, and that the identity of SF1 remains to be elucidated.

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Brown, Simone B., Raymond J. Turner, Rodney S. Roche, and Kenneth J. Stevenson. "Conformational analysis of thioredoxin using organoarsenical reagents as probes. A time-resolved fluorescence anisotropy and size exclusion chromatography study." Biochemistry and Cell Biology 67, no. 1 (January 1, 1989): 25–33. http://dx.doi.org/10.1139/o89-004.

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Reduced thioredoxin was subjected to chemical modification studies employing organoarsenical reagents specific for "spatially close" thiols. Modification was monitored by the loss in the free thiol content, by the percent incorporation of radiolabelled organoarsenical reagents, and by observing the changes in the amounts of the various thioredoxins by size exclusion chromatography. The rate of modification depends upon the polarity, rigidity, and size of the reagents. Small nonpolar organoarsenical reagents readily modified reduced thioredoxin, whereas polar and large reagents do not. Modifications resulted in the formation of stable 15-membered cyclodithioarsenite ring structures with no apparent changes in the secondary structure of the protein. Modification was reversed by the extrusion of the arsenical moiety by addition of 2,3-dimercaptopropanol. We have further characterized the oxidized, reduced, and modified thioredoxins by size exclusion chromatography and fluorescence anisotropy decay measurements. Both techniques show an increase in the hydrated volume of the protein upon reduction. Upon modification, the hydrodynamic volume of the protein further swells. Fluorescence anisotropy decay reveals that with modification there is loosening of the protein so that a "domain" containing the fluorophores can relax independently of the whole protein structure.Key words: thioredoxin, organoarsenical modification, protein conformation, size exclusion HPLC, fluorescence anisotropy.

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Mihara, Shoko, Kazunori Sugiura, Keisuke Yoshida, and Toru Hisabori. "Thioredoxin targets are regulated in heterocysts of cyanobacterium Anabaena sp. PCC 7120 in a light-independent manner." Journal of Experimental Botany 71, no. 6 (December 21, 2019): 2018–27. http://dx.doi.org/10.1093/jxb/erz561.

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Abstract In the nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120, glucose 6-phosphate dehydrogenase (G6PDH) plays an important role in producing the power for reducing nitrogenase under light conditions. Our previous study showed that thioredoxin suppresses G6PDH by reducing its activator protein OpcA, implying that G6PDH is inactivated under light conditions because thioredoxins are reduced by the photosynthetic electron transport system in cyanobacteria. To address how Anabaena sp. PCC 7120 maintains G6PDH activity even under light conditions when nitrogen fixation occurs, we investigated the redox regulation system in vegetative cells and specific nitrogen-fixing cells named heterocysts, individually. We found that thioredoxin target proteins were more oxidized in heterocysts than in vegetative cells under light conditions. Alterations in the redox regulation mechanism of heterocysts may affect the redox states of thioredoxin target proteins, including OpcA, so that G6PDH is activated in heterocysts even under light conditions.

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Kang, Zhenhui, Tong Qin, and Zhiping Zhao. "Thioredoxins and thioredoxin reductase in chloroplasts: A review." Gene 706 (July 2019): 32–42. http://dx.doi.org/10.1016/j.gene.2019.04.041.

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Ying, Sheng-Hua, Xiao-Hui Wang, and Ming-Guang Feng. "Characterization of a thioredoxin (BbTrx) from the entomopathogenic fungus Beauveria bassiana and its expression in response to thermal stress." Canadian Journal of Microbiology 56, no. 11 (November 2010): 934–42. http://dx.doi.org/10.1139/w10-081.

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A thioredoxin (BbTrx) was identified from the entomopathogenic fungus Beauveria bassiana . The cloned nucleotide sequence consisted of a 423-bp open reading frame encoding a 141-amino-acid thioredoxin, a 1011-bp 5′ region, and a 419-bp 3′ region. The deduced protein sequence of BbTrx, including a common 95-amino-acid conserved domain and a unique 46-amino-acid carboxy terminal region, was similar (≤38% identity) to that of other thioredoxins and phylogenetically closest to that from Neurospora crassa . In insulin solution containing dithiothreitol at 25 °C, recombinant BbTrx or a truncated form lacking the carboxy terminal region (BbTrxD) exhibited disulfide reduction activity. BbTrxD was more active after pre-incubation at 40–75 °C, and cells expressing BbTrxD showed significantly higher tolerance to thermal stress (51 °C). The BbTrx expression in B. bassiana was greatly elevated when stressed at 40 °C. The results indicate that the new thioredoxin is a potential target for improving the thermotolerance of B. bassiana formulations.

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Keselman, Anna, Ranjan Nath Pulak, Keren Moyal, and Noah Isakov. "PICOT: A Multidomain Protein with Multiple Functions." ISRN Immunology 2011 (October 19, 2011): 1–7. http://dx.doi.org/10.5402/2011/426095.

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The PICOT protein possesses three highly conserved regions that include an aminoterminal thioredoxin-like homology domain and a tandem repeat of a carboxyterminal PICOT homology domain with an overall conformation that resembles a glutaredoxin homology domain. In contrast to the classical dithiol thioredoxins and glutaredoxins, PICOT possesses a single cysteine residue in each of its three domains and is therefore distinct from the classical thioredoxin and glutaredoxin redox enzymes. Recent studies demonstrated that PICOT is a prerequisite for mouse embryogenesis and participates in several independent biological systems in the adult. This paper examines advances made over the past few years in understanding the role of PICOT in various biological systems.

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30

Muller, E. G. "A glutathione reductase mutant of yeast accumulates high levels of oxidized glutathione and requires thioredoxin for growth." Molecular Biology of the Cell 7, no. 11 (November 1996): 1805–13. http://dx.doi.org/10.1091/mbc.7.11.1805.

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A glutathione reductase null mutant of Saccharomyces cerevisiae was isolated in a synthetic lethal genetic screen for mutations which confer a requirement for thioredoxin. Yeast mutants that lack glutathione reductase (glr1 delta) accumulate high levels of oxidized glutathione and have a twofold increase in total glutathione. The disulfide form of glutathione increases 200-fold and represents 63% of the total glutathione in a glr1 delta mutant compared with only 6% in wild type. High levels of oxidized glutathione are also observed in a trx1 delta, trx2 delta double mutant (22% of total), in a glr1 delta, trx1 delta double mutant (71% of total), and in a glr1 delta, trx2 delta double mutant (69% of total). Despite the exceptionally high ratio of oxidized/reduced glutathione, the glr1 delta mutant grows with a normal cell cycle. However, either one of the two thioredoxins is essential for growth. Cells lacking both thioredoxins and glutathione reductase are not viable under aerobic conditions and grow poorly anaerobically. In addition, the glr1 delta mutant shows increased sensitivity to the thiol oxidant diamide. The sensitivity to diamide was suppressed by deletion of the TRX2 gene. The genetic analysis of thioredoxin and glutathione reductase in yeast runs counter to previous studies in Escherichia coli and for the first time links thioredoxin with the redox state of glutathione in vivo.

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Pérez-Pérez, María Esther, Alejandro Mata-Cabana, Ana María Sánchez-Riego, Marika Lindahl, and Francisco J. Florencio. "A Comprehensive Analysis of the Peroxiredoxin Reduction System in the Cyanobacterium Synechocystis sp. Strain PCC 6803 Reveals that All Five Peroxiredoxins Are Thioredoxin Dependent." Journal of Bacteriology 191, no. 24 (October 9, 2009): 7477–89. http://dx.doi.org/10.1128/jb.00831-09.

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ABSTRACT Cyanobacteria perform oxygenic photosynthesis, which gives rise to the continuous production of reactive oxygen species, such as superoxide anion radicals and hydrogen peroxide, particularly under unfavorable growth conditions. Peroxiredoxins, which are present in both chloroplasts and cyanobacteria, constitute a class of thiol-dependent peroxidases capable of reducing hydrogen peroxide as well as alkyl hydroperoxides. Chloroplast peroxiredoxins have been studied extensively and have been found to use a variety of endogenous electron donors, such as thioredoxins, glutaredoxins, or cyclophilin, to sustain their activities. To date, however, the endogenous reduction systems for cyanobacterial peroxiredoxins have not been systematically studied. We have expressed and purified all five Synechocystis sp. strain PCC 6803 peroxiredoxins, which belong to the classes 1-Cys Prx, 2-Cys Prx, type II Prx (PrxII), and Prx Q, and we have examined their capacities to interact with and receive electrons from the m-, x-, and y-type thioredoxins from the same organism, which are called TrxA, TrxB, and TrxQ, respectively. Assays for peroxidase activity demonstrated that all five enzymes could use thioredoxins as electron donors, whereas glutathione and Synechocystis sp. strain PCC 6803 glutaredoxins were inefficient. The highest catalytic efficiency was obtained for the couple consisting of PrxII and TrxQ thioredoxin. Studies of transcript levels for the peroxiredoxins and thioredoxins under different stress conditions highlighted the similarity between the PrxII and TrxQ thioredoxin expression patterns.

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Kunchithapautham, Kannan, B. Padmavathi, R. B. Narayanan, P. Kaliraj, and Alan L. Scott. "Thioredoxin from Brugia malayi: Defining a 16-Kilodalton Class of Thioredoxins from Nematodes." Infection and Immunity 71, no. 7 (July 2003): 4119–26. http://dx.doi.org/10.1128/iai.71.7.4119-4126.2003.

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ABSTRACT Thioredoxins are a family of small redox proteins that undergo NADPH-dependent reduction by thioredoxin reductase. This results in a supply of reducing equivalents that cells use in a wide variety of biological reactions, which include maintaining reduced forms of the enzymes important for protection against damage from high-energy oxygen radicals, the regulation of transcription factor activity, and the inhibition of apoptosis. Here we report on a new member of the thioredoxin family of proteins from the filarial nematode Brugia malayi, Bm-TRX-1, which defines a new subclass of 16-kDa thioredoxins that occur widely in nematodes, including Caenorhabditis elegans. In addition to being larger than the thioredoxins found in mammalian and bacterial species, the putative active site sequence of Bm-TRX-1, WCPPC, does not conform to the highly conserved WCGPC reported for thioredoxins from mammals to bacteria. Interestingly, an allelic form of Bm-TRX-1 was identified with an active site sequence WCPQC, which appears to be unique to the thioredoxins from filarial species. Bm-TRX-1 was between 98% and 35% identical to thioredoxins from other nematodes and ≈20% identical to the thioredoxins from mammals and Escherichia coli. Bm-TRX-1 was constitutively transcribed throughout the B. malayi life cycle, and Bm-TRX protein was detectable in somatic extracts and excretory-secretory products from adults and microfilariae. Recombinant Bm-TRX-1 had thiodisulfide reductase activity, as measured by the reduction of insulin, and protected DNA from the nicking activity of oxygen radicals. Overexpression of Bm-TRX-1 in a human monocyte cell line negatively regulated tumor necrosis factor alpha-induced p38 mitogen-activated protein kinase activity, suggesting a possible role of the 16-kDa Bm-TRX-1 in immunomodulation.

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Buchko, Garry W., Stephen N. Hewitt, Wesley C. Van Voorhis, and Peter J. Myler. "Solution NMR structures of oxidized and reducedEhrlichia chaffeensisthioredoxin: NMR-invisible structure owing to backbone dynamics." Acta Crystallographica Section F Structural Biology Communications 74, no. 1 (January 1, 2018): 46–56. http://dx.doi.org/10.1107/s2053230x1701799x.

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Thioredoxins are small ubiquitous proteins that participate in a diverse variety of redox reactionsviathe reversible oxidation of two cysteine thiol groups in a structurally conserved active site. Here, the NMR solution structures of a reduced and oxidized thioredoxin fromEhrlichia chaffeensis(Ec-Trx, ECH_0218), the etiological agent responsible for human monocytic ehrlichiosis, are described. The overall topology of the calculated structures is similar in both redox states and is similar to those of other thioredoxins: a five-stranded, mixed β-sheet (β1–β3–β2–β4–β5) surrounded by four α-helices. Unlike other thioredoxins studied by NMR in both redox states, the1H–15N HSQC spectrum of reducedEc-Trx was missing eight additional amide cross peaks relative to the spectrum of oxidizedEc-Trx. These missing amides correspond to residues Cys35–Glu39 in the active-site-containing helix (α2) and Ser72–Ile75 in a loop near the active site, and suggest a change in backbone dynamics on the millisecond-to-microsecond timescale associated with the breakage of an intramolecular Cys32–Cys35 disulfide bond in a thioredoxin. A consequence of the missing amide resonances is the absence of observable or unambiguous NOEs to provide the distance restraints necessary to define the N-terminal end of the α-helix containing the CPGC active site in the reduced state. This region adopts a well defined α-helical structure in other reported reduced thioredoxin structures, is mostly helical in oxidizedEc-Trx and CD studies ofEc-Trx in both redox states suggests there is no significant difference in the secondary structure of the protein. The NMR solution structure of reducedEc-Trx illustrates that the absence of canonical structure in a region of a protein may be owing to unfavorable dynamics prohibiting NOE observations or unambiguous NOE assignments.

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Bréhélin, Claire, Christophe Laloi, Aaron T. Setterdahl, David B. Knaff, and Yves Meyer. "Cytosolic, Mitochondrial Thioredoxins and Thioredoxin Reductases in Arabidopsis Thaliana." Photosynthesis Research 79, no. 3 (2004): 295–304. http://dx.doi.org/10.1023/b:pres.0000017165.55488.ca.

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35

Knaff, David B. "Oxidation-reduction properties of thioredoxins and thioredoxin-regulated enzymes." Physiologia Plantarum 110, no. 3 (July 18, 2008): 309–13. http://dx.doi.org/10.1111/j.1399-3054.2000.1100304.x.

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Knaff, David B. "Oxidation-reduction properties of thioredoxins and thioredoxin-regulated enzymes." Physiologia Plantarum 110, no. 3 (November 2000): 309–13. http://dx.doi.org/10.1034/j.1399-3054.2000.1100304.x.

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37

Holmgren, A. "Thioredoxin." Annual Review of Biochemistry 54, no. 1 (June 1985): 237–71. http://dx.doi.org/10.1146/annurev.bi.54.070185.001321.

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Yamawaki, Hideyuki, Judith Haendeler, and Bradford C. Berk. "Thioredoxin." Circulation Research 93, no. 11 (November 28, 2003): 1029–33. http://dx.doi.org/10.1161/01.res.0000102869.39150.23.

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HIROTA, KIICHI, HAJIME NAKAMURA, HIROSHI MASUTANI, and JUNJI YODOI. "Thioredoxin Superfamily and Thioredoxin-Inducing Agents." Annals of the New York Academy of Sciences 957, no. 1 (May 2002): 189–99. http://dx.doi.org/10.1111/j.1749-6632.2002.tb02916.x.

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40

BYKHOVSKI, ALEXEI, TATIANA GLOBUS, TATYANA KHROMOVA, BORIS GELMONT, and DWIGHT WOOLARD. "RESONANT TERAHERTZ SPECTROSCOPY OF BACTERIAL THIOREDOXIN IN WATER: SIMULATION AND EXPERIMENT." International Journal of High Speed Electronics and Systems 18, no. 01 (March 2008): 109–17. http://dx.doi.org/10.1142/s0129156408005187.

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The experimental and computational study of bacterial thioredoxin, an E. coli protein, at THz frequencies is presented. The absorption spectrum of the entire protein in water was studied numerically in the terahertz range (0.1 – 2 THz). In our work, the initial X-ray molecular structure of thioredoxin was optimized using the molecular dynamical (MD) simulations at room temperature and atmospheric pressure. The effect of a liquid content of a bacterial cell was taken into account explicitly via the simulation of water molecules using the TIP3P water model. Using atomic trajectories from the room-temperature MD simulations, thioredoxin's THz vibrational spectrum and the absorption coefficient were calculated in a quasi harmonic approximation. For our terahertz transmission measurements, we used solutions of thioredoxin in distilled water obtained from Sigma. The experimental and simulated signatures are correlated and dominant peaks are close in frequencies. The results of this study demonstrate that terahertz spectroscopy is a promising tool in generating spectral data for cellular components of bio agents such as bacterial cells and spores.

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Hess, Natalia, Simon Richter, Michael Liebthal, Karl-Josef Dietz, and Angelika Mustroph. "The Phosphofructokinase Isoform AtPFK5 Is a Novel Target of Plastidic Thioredoxin-f-Dependent Redox Regulation." Antioxidants 10, no. 3 (March 7, 2021): 401. http://dx.doi.org/10.3390/antiox10030401.

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The chloroplast primary metabolism is of central importance for plant growth and performance. Therefore, it is tightly regulated in order to adequately respond to multiple environmental conditions. A major fluctuation that plants experience each day is the change between day and night, i.e., the change between assimilation and dissimilation. Among other mechanisms, thioredoxin-mediated redox regulation is an important component of the regulation of plastid-localized metabolic enzymes. While assimilatory processes such as the Calvin–Benson cycle are activated under illumination, i.e., under reducing conditions, carbohydrate degradation is switched off during the day. Previous analyses have identified enzymes of the oxidative pentose phosphate pathway to be inactivated by reduction through thioredoxins. In this work, we present evidence that an enzyme of the plastidic glycolysis, the phosphofructokinase isoform AtPFK5, is also inactivated through reduction by thioredoxins, namely by thioredoxin-f. With the help of chemical oxidation, mutant analyses and further experiments, the highly conserved motif CXDXXC in AtPFK5 was identified as the target sequence for this regulatory mechanism. However, knocking out this isoform in plants had only very mild effects on plant growth and performance, indicating that the complex primary metabolism in plants can overcome a lack in AtPFK5 activity.

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AlOkda, Abdelrahman, and Jeremy M. Van Raamsdonk. "Evolutionarily Conserved Role of Thioredoxin Systems in Determining Longevity." Antioxidants 12, no. 4 (April 17, 2023): 944. http://dx.doi.org/10.3390/antiox12040944.

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Thioredoxin and thioredoxin reductase are evolutionarily conserved antioxidant enzymes that protect organisms from oxidative stress. These proteins also play roles in redox signaling and can act as a redox-independent cellular chaperone. In most organisms, there is a cytoplasmic and mitochondrial thioredoxin system. A number of studies have examined the role of thioredoxin and thioredoxin reductase in determining longevity. Disruption of either thioredoxin or thioredoxin reductase is sufficient to shorten lifespan in model organisms including yeast, worms, flies and mice, thereby indicating conservation across species. Similarly, increasing the expression of thioredoxin or thioredoxin reductase can extend longevity in multiple model organisms. In humans, there is an association between a specific genetic variant of thioredoxin reductase and lifespan. Overall, the cytoplasmic and mitochondrial thioredoxin systems are both important for longevity.

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KERN, Renée, Abderrahim MALKI, Arne HOLMGREN, and Gilbert RICHARME. "Chaperone properties of Escherichia coli thioredoxin and thioredoxin reductase." Biochemical Journal 371, no. 3 (May 1, 2003): 965–72. http://dx.doi.org/10.1042/bj20030093.

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Thioredoxin, thioredoxin reductase and NADPH form the thioredoxin system and are the major cellular protein disulphide reductase. We report here that Escherichia coli thioredoxin and thioredoxin reductase interact with unfolded and denatured proteins, in a manner similar to that of molecular chaperones that are involved in protein folding and protein renaturation after stress. Thioredoxin and/or thioredoxin reductase promote the functional folding of citrate synthase and α-glucosidase after urea denaturation. They also promote the functional folding of the bacterial galactose receptor, a protein without any cysteines. Furthermore, redox cycling of thioredoxin/thioredoxin reductase in the presence of NADPH and cystine stimulates the renaturation of the galactose receptor, suggesting that the thioredoxin system functions like a redox-powered chaperone machine. Thioredoxin reductase prevents the aggregation of citrate synthase under heat-shock conditions. It forms complexes that are more stable than those formed by thioredoxin with several unfolded proteins such as reduced carboxymethyl α-lactalbumin and unfolded bovine pancreatic trypsin inhibitor. These results suggest that the thioredoxin system, in addition to its protein disulphide isomerase activity possesses chaperone-like properties, and that its thioredoxin reductase component plays a major role in this function.

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Mallén-Ponce, Manuel J., María José Huertas, and Francisco J. Florencio. "Exploring the Diversity of the Thioredoxin Systems in Cyanobacteria." Antioxidants 11, no. 4 (March 28, 2022): 654. http://dx.doi.org/10.3390/antiox11040654.

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Cyanobacteria evolved the ability to perform oxygenic photosynthesis using light energy to reduce CO2 from electrons extracted from water and form nutrients. These organisms also developed light-dependent redox regulation through the Trx system, formed by thioredoxins (Trxs) and thioredoxin reductases (TRs). Trxs are thiol-disulfide oxidoreductases that serve as reducing substrates for target enzymes involved in numerous processes such as photosynthetic CO2 fixation and stress responses. We focus on the evolutionary diversity of Trx systems in cyanobacteria and discuss their phylogenetic relationships. The study shows that most cyanobacteria contain at least one copy of each identified Trx, and TrxA is the only one present in all genomes analyzed. Ferredoxin thioredoxin reductase (FTR) is present in all groups except Gloeobacter and Prochlorococcus, where there is a ferredoxin flavin-thioredoxin reductase (FFTR). Our data suggest that both TRs may have coexisted in ancestral cyanobacteria together with other evolutionarily related proteins such as NTRC or DDOR, probably used against oxidative stress. Phylogenetic studies indicate that they have different evolutionary histories. As cyanobacteria diversified to occupy new habitats, some of these proteins were gradually lost in some groups. Finally, we also review the physiological relevance of redox regulation in cyanobacteria through the study of target enzymes.

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Steinert, Peter, Karin Plank-Schumacher, Marisa Montemartini, Hans-Jürgen Hecht, and Leopold Flohé. "Permutation of the Active Site Motif of Tryparedoxin 2." Biological Chemistry 381, no. 3 (March 14, 2000): 211–19. http://dx.doi.org/10.1515/bc.2000.028.

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Abstract Tryparedoxins (TXN) are thioredoxinrelated proteins which, as trypanothione:peroxiredoxin oxidoreductases, constitute the trypanothionedependent antioxidant defense and may also serve as substrates for ribonucleotide reductase in trypanosomatids. The active site motif of TXN2, [40]WCPPCR[45], of Crithidia fasciculata was mutated by sitedirected mutagenesis and eight corresponding muteins were expressed in E. coli as terminally Histagged proteins, purified to homogeneity by nickel chelate chromatography, and characterized in terms of specific activity, specificity and, if possible, kinetics. Exchange of Cys41 and Cys44 by serine yielded inactive products confirming their presumed involvement in catalysis. Exchange of Arg45 by aspartate resulted in loss of activity, suggesting an activation of active site cysteines by the positive charge of Arg45. Substitution of Trp40 by phenylalanine or tyrosine resulted in moderate decrease of specific activity, as did exchange of Pro42 by glycine. Kinetic analysis of these three muteins revealed that primarily the reaction with trypanothione is affected by the mutations. Simulation of thioredoxin or glutaredoxin like active sites in TXN2 (P42G and W40T/P43Y, respectively) did not result in thioredoxin or glutaredoxin like activities. These data underscore that TXNs, although belonging to the thioredoxin superfamily, represent a group of enzymes distinct from thioredoxins and glutaredoxins in terms of specificity, and appear attractive as molecular targets for the design of trypanocidal compounds.

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Benáková, Štěpánka, Blanka Holendová, and Lydie Plecitá-Hlavatá. "Redox Homeostasis in Pancreatic β-Cells: From Development to Failure." Antioxidants 10, no. 4 (March 27, 2021): 526. http://dx.doi.org/10.3390/antiox10040526.

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Redox status is a key determinant in the fate of β-cell. These cells are not primarily detoxifying and thus do not possess extensive antioxidant defense machinery. However, they show a wide range of redox regulating proteins, such as peroxiredoxins, thioredoxins or thioredoxin reductases, etc., being functionally compartmentalized within the cells. They keep fragile redox homeostasis and serve as messengers and amplifiers of redox signaling. β-cells require proper redox signaling already in cell ontogenesis during the development of mature β-cells from their progenitors. We bring details about redox-regulated signaling pathways and transcription factors being essential for proper differentiation and maturation of functional β-cells and their proliferation and insulin expression/maturation. We briefly highlight the targets of redox signaling in the insulin secretory pathway and focus more on possible targets of extracellular redox signaling through secreted thioredoxin1 and thioredoxin reductase1. Tuned redox homeostasis can switch upon chronic pathological insults towards the dysfunction of β-cells and to glucose intolerance. These are characteristics of type 2 diabetes, which is often linked to chronic nutritional overload being nowadays a pandemic feature of lifestyle. Overcharged β-cell metabolism causes pressure on proteostasis in the endoplasmic reticulum, mainly due to increased demand on insulin synthesis, which establishes unfolded protein response and insulin misfolding along with excessive hydrogen peroxide production. This together with redox dysbalance in cytoplasm and mitochondria due to enhanced nutritional pressure impact β-cell redox homeostasis and establish prooxidative metabolism. This can further affect β-cell communication in pancreatic islets through gap junctions. In parallel, peripheral tissues losing insulin sensitivity and overall impairment of glucose tolerance and gut microbiota establish local proinflammatory signaling and later systemic metainflammation, i.e., low chronic inflammation prooxidative properties, which target β-cells leading to their dedifferentiation, dysfunction and eventually cell death.

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Yang, Jie-Lin, Dong-Qiang Zhao, and Li-Ying Feng. "Thioredoxin, thioredoxin-interacting protein and digestive diseases." World Chinese Journal of Digestology 19, no. 18 (2011): 1926. http://dx.doi.org/10.11569/wcjd.v19.i18.1926.

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Arnér, Elias S. J., and Arne Holmgren. "Physiological functions of thioredoxin and thioredoxin reductase." European Journal of Biochemistry 267, no. 20 (October 2000): 6102–9. http://dx.doi.org/10.1046/j.1432-1327.2000.01701.x.

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Holmgren, Arne. "Redox regulation by thioredoxin and thioredoxin reductase." BioFactors 11, no. 1-2 (2000): 63–64. http://dx.doi.org/10.1002/biof.5520110117.

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Garrigós, Víctor, Cecilia Picazo, Emilia Matallana, and Agustín Aranda. "Wine Yeast Peroxiredoxin TSA1 Plays a Role in Growth, Stress Response and Trehalose Metabolism in Biomass Propagation." Microorganisms 8, no. 10 (October 6, 2020): 1537. http://dx.doi.org/10.3390/microorganisms8101537.

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Peroxiredoxins are a family of peroxide-degrading enzymes for challenging oxidative stress. They receive their reducing power from redox-controlling proteins called thioredoxins, and these, in turn, from thioredoxin reductase. The main cytosolic peroxiredoxin is Tsa1, a moonlighting protein that also acts as protein chaperone a redox switch controlling some metabolic events. Gene deletion of peroxiredoxins in wine yeasts indicate that TSA1, thioredoxins and thioredoxin reductase TRR1 are required for normal growth in medium with glucose and sucrose as carbon sources. TSA1 gene deletion also diminishes growth in molasses, both in flasks and bioreactors. The TSA1 mutation brings about an expected change in redox parameters but, interestingly, it also triggers a variety of metabolic changes. It influences trehalose accumulation, lowering it in first molasses growth stages, but increasing it at the end of batch growth, when respiratory metabolism is set up. Glycogen accumulation at the entry of the stationary phase also increases in the tsa1Δ mutant. The mutation reduces fermentative capacity in grape juice, but the vinification profile does not significantly change. However, acetic acid and acetaldehyde production decrease when TSA1 is absent. Hence, TSA1 plays a role in the regulation of metabolic reactions leading to the production of such relevant enological molecules.

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Journal articles on the topic 'Thioredoxin'

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