scholarly journals Chaperone properties of Escherichia coli thioredoxin and thioredoxin reductase

2003 ◽  
Vol 371 (3) ◽  
pp. 965-972 ◽  
Author(s):  
Renée KERN ◽  
Abderrahim MALKI ◽  
Arne HOLMGREN ◽  
Gilbert RICHARME
Keyword(s):  
Escherichia Coli ◽  
Citrate Synthase ◽  
Thioredoxin Reductase ◽  
Cellular Protein ◽  
Unfolded Proteins ◽  
Urea Denaturation ◽  
Isomerase Activity ◽  
Protein Renaturation ◽  
Thioredoxin System ◽  
Pancreatic Trypsin Inhibitor

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.

Bacterial and mammalian thioredoxin systems activate iodothyronine 5′-deiodination

1988 ◽  
Vol 66 (5) ◽  
pp. 460-464 ◽  
Author(s):  
Arun K. Das ◽  
Brian C. W. Hummel ◽  
Florence K. Gleason ◽  
Arne Holmgren ◽  
Paul G. Walfish
Keyword(s):  
Escherichia Coli ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Thioredoxin Reductase ◽  
Relative Mass ◽  
Rat Liver Microsomes ◽  
Liver Cytosol ◽  
E Coli ◽  
Thioredoxin System ◽  
Rat Liver Cytosol

The identity of a dithiol (designated DFB) of relative mass (Mr) = 13 000, reported previously to be present infraction B of rat liver cytosol and to participate as a cofactor in the 5′-deiodination of iodothyronines, has been investigated. Substitution of highly purified thioredoxin from Escherichia coli for fraction B or of highly purified thioredoxin reductase from either E. coli or rat liver for cytosolic fraction A (containing DFB reductase) permits deiodination of 3,3′,5′-[l25I]triiodothyronine by rat liver microsomes to proceed. Addition of antibodies to highly purified rat-liver thioredoxin or thioredoxin reductase inhibits deiodination. Thus, the thioredoxin system largely accounts for the activity of the cytosolic cofactor system supporting 5′-deiodination of 3,3′,5′-triiodothyronine in rat liver.

scholarly journals Crystallization and Preliminary X-ray Characterization of Thioredoxin Reductase from Escherichia coli

1989 ◽  
Vol 264 (22) ◽  
pp. 12752-12753
Author(s):  
J Kuriyan ◽  
L Wong ◽  
M Russel ◽  
P Model
Keyword(s):  
Escherichia Coli ◽  
Thioredoxin Reductase ◽  
X Ray

Large-scale production of citrate synthase from a cloned gene

1982 ◽  
Vol 60 (12) ◽  
pp. 1143-1147 ◽  
Author(s):  
Harry W. Duckworth ◽  
Alexander W. Bell
Keyword(s):  
Escherichia Coli ◽  
Large Scale ◽  
Citrate Synthase ◽  
Specific Activity ◽  
Tetracycline Resistance ◽  
Scale Production ◽  
Ampicillin Resistance ◽  
Colicin E1 ◽  
Large Scale Production ◽  
Cloned Gene

Starting with a colicin E1 resistance recombinant plasmid which contains gltA, the gene for citrate synthase in Escherichia coli, we have constructed an ampicillin-resistance plasmid containing the gltA region as a 2.9-kilobase-pair insert in the tetracycline-resistance region of pBR322. Escherichia coli HB101 harbouring this plasmid, when grown on rich medium containing ampicillin, contains citrate synthase as about 8% of its soluble protein. The enzyme has been purified from this rich source and is identical to the chromosomal enzyme prepared previously in every property tested, except for specific activity, which is 64 U∙mg−1 as compared with 45–50 U∙mg−1 previously obtained. The N-terminal sequences of both enzymes are reported, and they are identical up to residue 16 at least. The overall yield of pure enzyme, starting with the cells grown in 15 L of medium, is 600–800 mg.

scholarly journals Antioxidant Activities and Selenogene Transcription in the European Sea Bass (Dicentrarchus labrax) Liver Depend, in a Non-linear Manner, on the Se/Hg Molar Ratio of the Feeds

2021 ◽  
Author(s):  
Marinelle Espino ◽  
Harkaitz Eguiraun ◽  
Oihane Diaz de Cerio ◽  
José Antonio Carrero ◽  
Nestor Etxebarria ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Dicentrarchus Labrax ◽  
Thioredoxin Reductase ◽  
Sea Bass ◽  
Molar Ratio ◽  
Antioxidant Systems ◽  
European Sea Bass ◽  
Thioredoxin System ◽  
Non Linear ◽  
Linear Manner

AbstractFeeding 3.9 and 6.7 mg Hg/kg (Se/Hg molar ratios of 0.8 and 0.4, respectively) for 14 days negatively affected Dicentrarchus labrax growth and total DNTB- and thioredoxin-reductase (TrxR) activities and the transcription of four redox genes (txn1, gpx1, txnrd3, and txnrd2) in the liver, but a diet with 0.5 mg Hg/kg (Se/Hg molar ratio 6.6) slightly increased both reductase activities and the transcription of txn1, gpx1, and txnrd2. Feeding 6.7 mg Hg/kg for 53 days downregulated the genes of the thioredoxin system (txn1, txnrd3, and txnrd2) but upregulated gpx1, confirming the previously proposed complementarity among the antioxidant systems. Substitution of 20% of the feed by thawed white fish (hake) slightly counteracted the negative effects of Hg. The effects were not statistically significant and were dependent, in a non-linear manner, on the Se/Hg molar ratio of the feed but not on its Hg concentration. These results stress the need to consider the Se/Hg molar ratio of the feed/food when evaluating the toxicity of Hg.

scholarly journals Protein Folding by Domain V of Escherichia coli 23S rRNA: Specificity of RNA-Protein Interactions

2008 ◽  
Vol 190 (9) ◽  
pp. 3344-3352 ◽  
Author(s):  
Dibyendu Samanta ◽  
Debashis Mukhopadhyay ◽  
Saheli Chowdhury ◽  
Jaydip Ghosh ◽  
Saumen Pal ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Protein Folding ◽  
Carbonic Anhydrase ◽  
Protein Interactions ◽  
23S Rrna ◽  
Unfolded Proteins ◽  
Bovine Carbonic Anhydrase ◽  
Egg White Lysozyme ◽  
General Protein ◽  
Domain V

ABSTRACT The peptidyl transferase center, present in domain V of 23S rRNA of eubacteria and large rRNA of plants and animals, can act as a general protein folding modulator. Here we show that a few specific nucleotides in Escherichia coli domain V RNA bind to unfolded proteins and, as shown previously, bring the trapped proteins to a folding-competent state before releasing them. These nucleotides are the same for the proteins studied so far: bovine carbonic anhydrase, lactate dehydrogenase, malate dehydrogenase, and chicken egg white lysozyme. The amino acids that interact with these nucleotides are also found to be specific in the two cases tested: bovine carbonic anhydrase and lysozyme. They are either neutral or positively charged and are present in random coils on the surface of the crystal structure of both the proteins. In fact, two of these amino acid-nucleotide pairs are identical in the two cases. How these features might help the process of protein folding is discussed.

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