Regulation of the catalytic activity and structure of human thioredoxin 1 via oxidation and S-nitrosylation of cysteine residues

Hashemy, S. I. and Holmgren, A. (2008) Regulation of the catalytic activity and structure of human thioredoxin 1 via oxidation and S-nitrosylation of cysteine residues. Journal of Biological Chemistry, 283 (32). pp. 21890-21898.

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The mammalian cytosolic/nuclear thioredoxin system, comprising thioredoxin (Trx), selenoenzyme thioredoxin reductase (TrxR), and NADPH, is the major protein-disulfide reductase of the cell and has numerous functions. The active site of reduced Trx comprises Cys32-Gly-Pro-Cys35 thiols that catalyze target disulfide reduction, generating a disulfide. Human Trx1 has also three structural Cys residues in positions 62, 69, and 73 that upon diamide oxidation induce a second Cys62-Cys69 disulfide as well as dimers and multimers. We have discovered that after incubation with H2O2 only monomeric two-disulfide molecules are generated, and they are inactive but able to regain full activity in an autocatalytic process in the presence of NADPH and TrxR. There are conflicting results regarding the effects of S-nitrosylation on Trx antioxidant functions and which residues are involved. We found that S-nitrosoglutathione-mediated S-nitrosylation at physiological pH is critically dependent on the redox state of Trx. Starting from fully reduced human Trx, both Cys68 and Cys73 were nitrosylated, and the active site formed a disulfide; the nitrosylated Trx was not a substrate for TrxR but regained activity after a lag phase consistent with autoactivation. Treatment of a two-disulfide form of Trx1 with S-nitrosoglutathione resulted in nitrosylation of Cys73, which can act as a trans-nitrosylating agent as observed by others to control caspase 3 activity (Mitchell, D. A., and Marletta, M. A. (2005) Nat. Chem. Biol. 1, 154-158). The reversible inhibition of human Trx1 activity by H 2O2 and NO donors is suggested to act in cell signaling via temporal control of reduction for the transmission of oxidative and/or nitrosative signals in thiol redox control. © 2008 by The American Society for Biochemistry and Molecular Biology, Inc.

Item Type: Article
Additional Information: Cited By :113 Export Date: 16 February 2020 CODEN: JBCHA Correspondence Address: Holmgren, A.; Medical Nobel Inst. for Biochemistry, Dept. of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden; email:
Uncontrolled Keywords: Biomechanics Catalytic oxidation Mammals Oligomers Oxidation pH pH effects Respiratory mechanics Active sites Anti-oxidants Autoactivation Autocatalytic processes Caspase-3 Catalytic activities Cys residues Cysteine residues Diamide Disulfide reductases In cells Multimers Nitrosylation NO donors Redox states Reversible inhibitions Temporal controls Thioredoxin Thioredoxin reductases Proteins cysteine disulfide hydrogen peroxide insulin nitric oxide reactive oxygen metabolite reduced nicotinamide adenine dinucleotide phosphate s nitrosoglutathione thiol derivative thioredoxin reductase thioredoxin reductase 1 nitric oxide donor oxidizing agent proline thiol reagent antioxidant activity article disulfide bond enzyme active site enzyme activity enzyme assay enzyme structure enzyme substrate Escherichia coli human nonhuman oxidation reduction reaction polyacrylamide gel electrophoresis priority journal spectrophotometry catalysis chemical structure chemistry drug effect metabolism protein tertiary structure time Mammalia Humans Models, Molecular Nitric Oxide Donors Oxidants Oxidation-Reduction Protein Structure, Tertiary S-Nitrosoglutathione Sulfhydryl Reagents Thioredoxins Time Factors
Subjects: QU Biochemistry
Divisions: Mashhad University of Medical Sciences
Depositing User: mr lib3 lib3
Date Deposited: 29 Apr 2020 04:54
Last Modified: 29 Apr 2020 04:54

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