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Bravo-Chaucanés CP, Abadio AKR, Kioshima ÉS, Felipe MSS, Barbosa JARG. Crystal structure of thioredoxin 1 from Cryptococcus neoformans at 1.8 Å resolution shows unexpected plasticity of the loop preceding the catalytic site. Biochem Biophys Rep 2020; 21:100724. [PMID: 32021910 PMCID: PMC6994535 DOI: 10.1016/j.bbrep.2019.100724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 11/19/2019] [Accepted: 12/28/2019] [Indexed: 11/26/2022] Open
Abstract
An elevated prevalence of cryptococcal infection is a tendency in low-income countries and constitutes a global public health problem due to factors such as the limited efficacy of antifungal therapy and the AIDS/transplant immunocompromised patients. The fungus Cryptococcus neoformans, implicated in this burden, has had several genes validated as drug targets. Among them, the thioredoxin system is one of the major regulators of redox homeostasis and antioxidant defense acting on protein disulfide bonds. Thioredoxin 1 from C. neoformans (CnTrx1) was cloned and expressed in E. coli and the recombinant protein was purified and crystallized. Functional assay shows that CnTrx1 catalyzes the reduction of insulin disulfide bonds using dithiothreitol, while acting as a monomer in solution. The crystal structure of oxidized CnTrx1 at 1.80 Å resolution presents a dimer in the asymmetric unit with typical Trx-fold. Differences between the monomers in the asymmetric unit are found specially in the loop leading to the Cys-Gly-Pro-Cys active-site motif, being even larger when compared to those found between reduced and oxidized states of other thioredoxins. Although the thioredoxins have been isolated and characterized from many organisms, this new structural report provides important clues for understanding the binding and specificity of CnTrx1 to its targets.
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Affiliation(s)
- Claudia Patricia Bravo-Chaucanés
- Laboratório de Biofísica Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF, Brazil
| | | | | | - Maria Sueli Soares Felipe
- Universidade Católica de Brasília, Pós-Graduação em Ciências Genômicas e Biotecnologia, Brasília, DF, Brazil
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2
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Structural and Biochemical Insights into the Reactivity of Thioredoxin h1 from Chlamydomonas reinhardtii. Antioxidants (Basel) 2019; 8:antiox8010010. [PMID: 30609656 PMCID: PMC6356897 DOI: 10.3390/antiox8010010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 12/14/2018] [Accepted: 12/18/2018] [Indexed: 02/07/2023] Open
Abstract
Thioredoxins (TRXs) are major protein disulfide reductases of the cell. Their redox activity relies on a conserved Trp-Cys-(Gly/Pro)-Pro-Cys active site bearing two cysteine (Cys) residues that can be found either as free thiols (reduced TRXs) or linked together by a disulfide bond (oxidized TRXs) during the catalytic cycle. Their reactivity is crucial for TRX activity, and depends on the active site microenvironment. Here, we solved and compared the 3D structure of reduced and oxidized TRX h1 from Chlamydomonas reinhardtii (CrTRXh1). The three-dimensional structure was also determined for mutants of each active site Cys. Structural alignments of CrTRXh1 with other structurally solved plant TRXs showed a common spatial fold, despite the low sequence identity. Structural analyses of CrTRXh1 revealed that the protein adopts an identical conformation independently from its redox state. Treatment with iodoacetamide (IAM), a Cys alkylating agent, resulted in a rapid and pH-dependent inactivation of CrTRXh1. Starting from fully reduced CrTRXh1, we determined the acid dissociation constant (pKa) of each active site Cys by Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry analyses coupled to differential IAM-based alkylation. Based on the diversity of catalytic Cys deprotonation states, the mechanisms and structural features underlying disulfide redox activity are discussed.
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3
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Lemaire SD, Tedesco D, Crozet P, Michelet L, Fermani S, Zaffagnini M, Henri J. Crystal Structure of Chloroplastic Thioredoxin f2 from Chlamydomonas reinhardtii Reveals Distinct Surface Properties. Antioxidants (Basel) 2018; 7:E171. [PMID: 30477165 PMCID: PMC6316601 DOI: 10.3390/antiox7120171] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/13/2018] [Accepted: 11/20/2018] [Indexed: 12/14/2022] Open
Abstract
Protein disulfide reduction by thioredoxins (TRXs) controls the conformation of enzyme active sites and their multimeric complex formation. TRXs are small oxidoreductases that are broadly conserved in all living organisms. In photosynthetic eukaryotes, TRXs form a large multigenic family, and they have been classified in different types: f, m, x, y, and z types are chloroplastic, while o and h types are located in mitochondria and cytosol. In the model unicellular alga Chlamydomonas reinhardtii, the TRX family contains seven types, with f- and h-types represented by two isozymes. Type-f TRXs interact specifically with targets in the chloroplast, controlling photosynthetic carbon fixation by the Calvin⁻Benson cycle. We solved the crystal structures of TRX f2 and TRX h1 from C. reinhardtii. The systematic comparison of their atomic features revealed a specific conserved electropositive crown around the active site of TRX f, complementary to the electronegative surface of their targets. We postulate that this surface provides specificity to each type of TRX.
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Affiliation(s)
- Stéphane D Lemaire
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 8226 CNRS Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Daniele Tedesco
- Bio-Pharmaceutical Analysis Section (Bio-PhASe), Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy.
| | - Pierre Crozet
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 8226 CNRS Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Laure Michelet
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 8226 CNRS Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Simona Fermani
- Department of Chemistry "Giacomo Ciamician", University of Bologna, via Selmi 2, 40126 Bologna, Italy.
| | - Mirko Zaffagnini
- Laboratory of Molecular Plant Physiology, Department of Pharmacy and Biotechnology, University of Bologna, via Irnerio 42, 40126 Bologna, Italy.
| | - Julien Henri
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 8226 CNRS Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France.
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4
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Zhang W, Niu X, Ding J, Hu Y, Jin C. Intra- and inter-protein couplings of backbone motions underlie protein thiol-disulfide exchange cascade. Sci Rep 2018; 8:15448. [PMID: 30337655 PMCID: PMC6193951 DOI: 10.1038/s41598-018-33766-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/06/2018] [Indexed: 11/09/2022] Open
Abstract
The thioredoxin (Trx)-coupled arsenate reductase (ArsC) is a family of enzymes that catalyzes the reduction of arsenate to arsenite in the arsenic detoxification pathway. The catalytic cycle involves a series of relayed intramolecular and intermolecular thiol-disulfide exchange reactions. Structures at different reaction stages have been determined, suggesting significant conformational fluctuations along the reaction pathway. Herein, we use two state-of-the-art NMR methods, the chemical exchange saturation transfer (CEST) and the CPMG-based relaxation dispersion (CPMG RD) experiments, to probe the conformational dynamics of B. subtilis ArsC in all reaction stages, namely the enzymatic active reduced state, the intra-molecular C10-C82 disulfide-bonded intermediate state, the inactive oxidized state, and the inter-molecular disulfide-bonded protein complex with Trx. Our results reveal highly rugged energy landscapes in the active reduced state, and suggest global collective motions in both the C10-C82 disulfide-bonded intermediate and the mixed-disulfide Trx-ArsC complex.
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Affiliation(s)
- Wenbo Zhang
- College of Life Sciences, Peking University, Beijing, 100871, China.,Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, 100871, China
| | - Xiaogang Niu
- College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.,Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, 100871, China
| | - Jienv Ding
- College of Life Sciences, Peking University, Beijing, 100871, China.,Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, 100871, China.,National Institutes of Health, DHHS 1050 Boyles Street, Frederick, MD, 21702, USA
| | - Yunfei Hu
- College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China. .,Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, 100871, China. .,Medical College of Soochow University, Suzhou, 215123, China.
| | - Changwen Jin
- College of Life Sciences, Peking University, Beijing, 100871, China. .,College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China. .,Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, 100871, China. .,Beijing National Laboratory for Molecular Sciences, Peking University, Beijing, 100871, China.
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5
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Trost P, Fermani S, Calvaresi M, Zaffagnini M. Biochemical basis of sulphenomics: how protein sulphenic acids may be stabilized by the protein microenvironment. PLANT, CELL & ENVIRONMENT 2017; 40:483-490. [PMID: 27390911 DOI: 10.1111/pce.12791] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/17/2016] [Accepted: 06/20/2016] [Indexed: 05/04/2023]
Abstract
Among protein residues, cysteines are one of the prominent candidates to ROS-mediated and RNS-mediated post-translational modifications, and hydrogen peroxide (H2 O2 ) is the main ROS candidate for inducing cysteine oxidation. The reaction with H2 O2 is not common to all cysteine residues, being their reactivity an utmost prerequisite for the sensitivity towards H2 O2 . Indeed, only deprotonated Cys (i.e. thiolate form, S- ) can react with H2 O2 leading to sulphenic acid formation (SOH), which is considered as a major/central player of ROS sensing pathways. However, cysteine sulphenic acids are generally unstable because they can be further oxidized to irreversible forms (sulphinic and sulphonic acids, SO2 H and SO3 H, respectively), or alternatively, they can proceed towards further modifications including disulphide bond formation (SS), S-glutathionylation (SSG) and sulphenamide formation (SN). To understand why and how cysteine residues undergo primary oxidation to sulphenic acid, and to explore the stability of cysteine sulphenic acids, a combination of biochemical, structural and computational studies are required. Here, we will discuss the current knowledge of the structural determinants for cysteine reactivity and sulphenic acid stability within protein microenvironments.
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Affiliation(s)
- P Trost
- Department of Pharmacy and Biotechnologies, University of Bologna, Bologna, Italy
| | - S Fermani
- Department of Chemistry "G. Ciamician", University of Bologna, Bologna, Italy
| | - M Calvaresi
- Department of Chemistry "G. Ciamician", University of Bologna, Bologna, Italy
| | - M Zaffagnini
- Department of Pharmacy and Biotechnologies, University of Bologna, Bologna, Italy
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6
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Selles B, Zannini F, Couturier J, Jacquot JP, Rouhier N. Atypical protein disulfide isomerases (PDI): Comparison of the molecular and catalytic properties of poplar PDI-A and PDI-M with PDI-L1A. PLoS One 2017; 12:e0174753. [PMID: 28362814 PMCID: PMC5375154 DOI: 10.1371/journal.pone.0174753] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 03/14/2017] [Indexed: 11/18/2022] Open
Abstract
Protein disulfide isomerases are overwhelmingly multi-modular redox catalysts able to perform the formation, reduction or isomerisation of disulfide bonds. We present here the biochemical characterization of three different poplar PDI isoforms. PDI-A is characterized by a single catalytic Trx module, the so-called a domain, whereas PDI-L1a and PDI-M display an a-b-b’-a’ and a°-a-b organisation respectively. Their activities have been tested in vitro using purified recombinant proteins and a series of model substrates as insulin, NADPH thioredoxin reductase, NADP malate dehydrogenase (NADP-MDH), peroxiredoxins or RNase A. We demonstrated that PDI-A exhibited none of the usually reported activities, although the cysteines of the WCKHC active site signature are able to form a disulfide with a redox midpoint potential of -170 mV at pH 7.0. The fact that it is able to bind a [Fe2S2] cluster upon Escherichia coli expression and anaerobic purification might indicate that it does not have a function in dithiol-disulfide exchange reactions. The two other proteins were able to catalyze oxidation or reduction reactions, PDI-L1a being more efficient in most cases, except that it was unable to activate the non-physiological substrate NADP-MDH, in contrast to PDI-M. To further evaluate the contribution of the catalytic domains of PDI-M, the dicysteinic motifs have been independently mutated in each a domain. The results indicated that the two a domains seem interconnected and that the a° module preferentially catalyzed oxidation reactions whereas the a module catalyzed reduction reactions, in line with the respective redox potentials of -170 mV and -190 mV at pH 7.0. Overall, these in vitro results illustrate that the number and position of a and b domains influence the redox properties and substrate recognition (both electron donors and acceptors) of PDI which contributes to understand why this protein family expanded along evolution.
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Affiliation(s)
- Benjamin Selles
- UMR 1136 Interactions Arbres/Microorganismes, Université de Lorraine/ INRA, Faculté des Sciences et Technologies, Vandoeuvre-lès-Nancy, France
| | - Flavien Zannini
- UMR 1136 Interactions Arbres/Microorganismes, Université de Lorraine/ INRA, Faculté des Sciences et Technologies, Vandoeuvre-lès-Nancy, France
| | - Jérémy Couturier
- UMR 1136 Interactions Arbres/Microorganismes, Université de Lorraine/ INRA, Faculté des Sciences et Technologies, Vandoeuvre-lès-Nancy, France
| | - Jean-Pierre Jacquot
- UMR 1136 Interactions Arbres/Microorganismes, Université de Lorraine/ INRA, Faculté des Sciences et Technologies, Vandoeuvre-lès-Nancy, France
| | - Nicolas Rouhier
- UMR 1136 Interactions Arbres/Microorganismes, Université de Lorraine/ INRA, Faculté des Sciences et Technologies, Vandoeuvre-lès-Nancy, France
- * E-mail:
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7
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Iqbal A, Moraes AH, Valente AP, Almeida FCL. Structures of the reduced and oxidized state of the mutant D24A of yeast thioredoxin 1: insights into the mechanism for the closing of the water cavity. JOURNAL OF BIOMOLECULAR NMR 2015; 63:417-423. [PMID: 26482062 DOI: 10.1007/s10858-015-9996-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 10/14/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Anwar Iqbal
- Institute of Medical Biochemistry, National Center of Nuclear Magnetic Resonance Jiri Jonas, Federal University of Rio de Janeiro, Av. Carlos Chagas Filho, 373 CCS/Anexo CNRMN, Rio de Janeiro, RJ, 21941-920, Brazil
- Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adolfo Henrique Moraes
- Institute of Medical Biochemistry, National Center of Nuclear Magnetic Resonance Jiri Jonas, Federal University of Rio de Janeiro, Av. Carlos Chagas Filho, 373 CCS/Anexo CNRMN, Rio de Janeiro, RJ, 21941-920, Brazil
- Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Paula Valente
- Institute of Medical Biochemistry, National Center of Nuclear Magnetic Resonance Jiri Jonas, Federal University of Rio de Janeiro, Av. Carlos Chagas Filho, 373 CCS/Anexo CNRMN, Rio de Janeiro, RJ, 21941-920, Brazil
- Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fabio C L Almeida
- Institute of Medical Biochemistry, National Center of Nuclear Magnetic Resonance Jiri Jonas, Federal University of Rio de Janeiro, Av. Carlos Chagas Filho, 373 CCS/Anexo CNRMN, Rio de Janeiro, RJ, 21941-920, Brazil.
- Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
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8
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Kirkensgaard KG, Hägglund P, Shahpiri A, Finnie C, Henriksen A, Svensson B. A novel twist on molecular interactions between thioredoxin and nicotinamide adenine dinucleotide phosphate-dependent thioredoxin reductase. Proteins 2013; 82:607-19. [PMID: 24123219 DOI: 10.1002/prot.24437] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/19/2013] [Accepted: 09/26/2013] [Indexed: 12/31/2022]
Abstract
The ubiquitous disulfide reductase thioredoxin (Trx) regulates several important biological processes such as seed germination in plants. Oxidized cytosolic Trx is regenerated by nicotinamide adenine dinucleotide phosphate (NADPH)-dependent thioredoxin reductase (NTR) in a multistep transfer of reducing equivalents from NADPH to Trx via a tightly NTR-bound flavin. Here, interactions between NTR and Trx are predicted by molecular modelling of the barley NTR:Trx complex (HvNTR2:HvTrxh2) and probed by site directed mutagenesis. Enzyme kinetics analysis reveals mutants in a loop of the flavin adenine dinucleotide (FAD)-binding domain of HvNTR2 to strongly affect the interaction with Trx. In particular, Trp42 and Met43 play key roles for recognition of the endogenous HvTrxh2. Trx from Arabidopsis thaliana is also efficiently recycled by HvNTR2 but turnover in this case appears to be less dependent on these two residues, suggesting a distinct mode for NTR:Trx recognition. Comparison between the HvNTR2:HvTrxh2 model and the crystal structure of the Escherichia coli NTR:Trx complex reveals major differences in interactions involving the FAD- and NADPH-binding domains as supported by our experiments. Overall, the findings suggest that NTR:Trx interactions in different biological systems are fine-tuned by multiple intermolecular contacts.
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Affiliation(s)
- Kristine G Kirkensgaard
- Enzyme and Protein Chemistry Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark; The Protein Chemistry Group, Carlsberg Laboratory, DK-1799 København V, Denmark
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9
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Cheng Z, Zhang J, Ballou DP, Williams CH. Reactivity of thioredoxin as a protein thiol-disulfide oxidoreductase. Chem Rev 2011; 111:5768-83. [PMID: 21793530 DOI: 10.1021/cr100006x] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Zhiyong Cheng
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-5606, USA
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10
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Mottonen JM, Xu M, Jacobs DJ, Livesay DR. Unifying mechanical and thermodynamic descriptions across the thioredoxin protein family. Proteins 2009; 75:610-27. [PMID: 19004018 DOI: 10.1002/prot.22273] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We compare various predicted mechanical and thermodynamic properties of nine oxidized thioredoxins (TRX) using a Distance Constraint Model (DCM). The DCM is based on a nonadditive free energy decomposition scheme, where entropic contributions are determined from rigidity and flexibility of structure based on distance constraints. We perform averages over an ensemble of constraint topologies to calculate several thermodynamic and mechanical response functions that together yield quantitative stability/flexibility relationships (QSFR). Applied to the TRX protein family, QSFR metrics display a rich variety of similarities and differences. In particular, backbone flexibility is well conserved across the family, whereas cooperativity correlation describing mechanical and thermodynamic couplings between the residue pairs exhibit distinctive features that readily standout. The diversity in predicted QSFR metrics that describe cooperativity correlation between pairs of residues is largely explained by a global flexibility order parameter describing the amount of intrinsic flexibility within the protein. A free energy landscape is calculated as a function of the flexibility order parameter, and key values are determined where the native-state, transition-state, and unfolded-state are located. Another key value identifies a mechanical transition where the global nature of the protein changes from flexible to rigid. The key values of the flexibility order parameter help characterize how mechanical and thermodynamic response is linked. Variation in QSFR metrics and key characteristics of global flexibility are related to the native state X-ray crystal structure primarily through the hydrogen bond network. Furthermore, comparison of three TRX redox pairs reveals differences in thermodynamic response (i.e., relative melting point) and mechanical properties (i.e., backbone flexibility and cooperativity correlation) that are consistent with experimental data on thermal stabilities and NMR dynamical profiles. The results taken together demonstrate that small-scale structural variations are amplified into discernible global differences by propagating mechanical couplings through the H-bond network.
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Affiliation(s)
- James M Mottonen
- Department of Physics and Optical Science, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
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11
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Chung JS, Noguera-Mazon V, Lancelin JM, Kim SK, Hirasawa M, Hologne M, Leustek T, Knaff DB. Interaction domain on thioredoxin for Pseudomonas aeruginosa 5'-adenylylsulfate reductase. J Biol Chem 2009; 284:31181-9. [PMID: 19744922 DOI: 10.1074/jbc.m109.035634] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
NMR spectroscopy has been used to map the interaction domain on Escherichia coli thioredoxin for the thioredoxin- dependent 5'-adenylylsulfate reductase from Pseudomonas aeruginosa (PaAPR). Seventeen thioredoxin amino acids, all clustered around Cys-32 (the more surface-exposed of the two active-site cysteines), have been located at the PaAPR binding site. The center of the binding domain is dominated by nonpolar amino acids, with a smaller number of charged and polar amino acids located on the periphery of the site. Twelve of the amino acids detected by NMR have non-polar, hydrophobic side chains, including one aromatic amino acid (Trp-31). Four of the thioredoxin amino acids at the PaAPR binding site have polar side chains (Lys-36, Asp-61, Gln-62 and Arg-73), with three of the four having charged side chains. Site-directed mutagenesis experiments have shown that replacement of Lys-36, Asp-61, and Arg-73 and of the absolutely conserved Trp-31 significantly decreases the V(max) for the PaAPR-catalyzed reduction of 5'-adenylylsulfate, with E. coli thioredoxin serving as the electron donor. The most dramatic effect was observed with the W31A variant, which showed no activity as a donor to PaAPR. Although the thiol of the active-site Cys-256 of PaAPR is the point of the initial nucleophilic attack by reduced thioredoxin, mutagenic replacement of Cys-256 by serine has no effect on thioredoxin binding to PaAPR.
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Affiliation(s)
- Jung-Sung Chung
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, USA
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12
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Abstract
The dissociation mechanism of the thioredoxin (Trx) mixed disulfide complexes is unknown and has been debated for more than twenty years. Specifically, opposing arguments for the activation of the nucleophilic cysteine as a thiolate during the dissociation of the complex have been put forward. As a key model, the complex between Trx and its endogenous substrate, arsenate reductase (ArsC), was used. In this structure, a Cys29Trx-Cys89ArsC intermediate disulfide is formed by the nucleophilic attack of Cys29Trx on the exposed Cys82ArsC-Cys89ArsC in oxidized ArsC. With theoretical reactivity analysis, molecular dynamics simulations, and biochemical complex formation experiments with Cys-mutants, Trx mixed disulfide dissociation was studied. We observed that the conformational changes around the intermediate disulfide bring Cys32Trx in contact with Cys29Trx. Cys32Trx is activated for its nucleophilic attack by hydrogen bonds, and Cys32Trx is found to be more reactive than Cys82ArsC. Additionally, Cys32Trx directs its nucleophilic attack on the more susceptible Cys29Trx and not on Cys89ArsC. This multidisciplinary approach provides fresh insights into a universal thiol/disulfide exchange reaction mechanism that results in reduced substrate and oxidized Trx. Thioredoxins are found in all types of cells and control several essential functions of life, including promotion of cell growth, inhibition of apoptosis, and modulation of inflammation. Thioredoxin has two ‘free’ cysteines in its active site, which are used to break disulfide bonds in oxidized substrate proteins. In the first step, an intermediate thioredoxin-protein complex is formed, which is broken in the second step, releasing the substrate protein in its reduced state. In other words, the disulfide is being transferred from the substrate protein to thioredoxin, or the electrons coming from thioredoxin are shuttled to the protein substrate. The exact reaction mechanism, i.e., the detailed succession of steps in which the reaction takes place, of how this mixed disulfide is broken is not known and has been debated over the last twenty years. With a multidisciplinary approach, combining computational and experimental work, we provide fresh insights into how conformational changes activate the catalytic cysteines with which this universal reduction mechanism is completed with the correct regioselectivity. This work illustrates the strengths of computational approaches in probing phenomena which are otherwise very difficult to investigate experimentally.
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13
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Jacquot JP, Eklund H, Rouhier N, Schürmann P. Structural and evolutionary aspects of thioredoxin reductases in photosynthetic organisms. TRENDS IN PLANT SCIENCE 2009; 14:336-43. [PMID: 19446492 DOI: 10.1016/j.tplants.2009.03.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 03/27/2009] [Accepted: 03/31/2009] [Indexed: 05/24/2023]
Abstract
Thioredoxins (Trxs) are small oxidoreductases that are involved in redox homeostasis and are found in large numbers in the subcellular compartments of eukaryotic plant cells, including the chloroplasts. Also present in chloroplasts are two forms of thioredoxin reductase (TR), which use either NADPH or ferredoxin as an electron donor. In other compartments, two additional TR forms also use NADPH: one is distributed in all photosynthetic organisms and is similar to prokaryotic enzymes, whereas the other is restricted to algae and is similar to mammalian selenoproteins. Here, we review current knowledge of the different forms of TRs across organisms and discuss the possible evolutionary fate of this class of enzymes, which provide an example of convergent functional evolution.
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Affiliation(s)
- Jean-Pierre Jacquot
- Interactions Arbres Microorganismes UMR 1136, IFR 110, Nancy University, BP 239, 54506 Vandoeuvre Cedex, France.
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14
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Dangoor I, Peled-Zehavi H, Levitan A, Pasand O, Danon A. A small family of chloroplast atypical thioredoxins. PLANT PHYSIOLOGY 2009; 149:1240-50. [PMID: 19109414 PMCID: PMC2649386 DOI: 10.1104/pp.108.128314] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Accepted: 12/22/2008] [Indexed: 05/23/2023]
Abstract
The reduction and the formation of regulatory disulfide bonds serve as a key signaling element in chloroplasts. Members of the thioredoxin (Trx) superfamily of oxidoreductases play a major role in these processes. We have characterized a small family of plant-specific Trxs in Arabidopsis (Arabidopsis thaliana) that are rich in cysteine and histidine residues and are typified by a variable noncanonical redox active site. We found that the redox midpoint potential of three selected family members is significantly less reducing than that of the classic Trxs. Assays of subcellular localization demonstrated that all proteins are localized to the chloroplast. Selected members showed high activity, contingent on a dithiol electron donor, toward the chloroplast 2-cysteine peroxiredoxin A and poor activity toward the chloroplast NADP-malate dehydrogenase. The expression profile of the family members suggests that they have distinct roles. The intermediate redox midpoint potential value of the atypical Trxs might imply adaptability to function in modulating the redox state of chloroplast proteins with regulatory disulfides.
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Affiliation(s)
- Inbal Dangoor
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
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15
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Dubey S, Idicula-Thomas S, Anwaruddin M, Saravanan C, Varma RR, Maitra A. A novel 9-bp insertion detected in steroid 21-hydroxylase gene (CYP21A2): prediction of its structural and functional implications by computational methods. J Biomed Sci 2009; 16:3. [PMID: 19272182 PMCID: PMC2653521 DOI: 10.1186/1423-0127-16-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Accepted: 01/08/2009] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Steroid 21-hydroxylase deficiency is the most common cause of congenital adrenal hyperplasia (CAH). Detection of underlying mutations in CYP21A2 gene encoding steroid 21-hydroxylase enzyme is helpful both for confirmation of diagnosis and management of CAH patients. Here we report a novel 9-bp insertion in CYP21A2 gene and its structural and functional consequences on P450c21 protein by molecular modeling and molecular dynamics simulations methods. METHODS A 30-day-old child was referred to our laboratory for molecular diagnosis of CAH. Sequencing of the entire CYP21A2 gene revealed a novel insertion (duplication) of 9-bp in exon 2 of one allele and a well-known mutation I172N in exon 4 of other allele. Molecular modeling and simulation studies were carried out to understand the plausible structural and functional implications caused by the novel mutation. RESULTS Insertion of the nine bases in exon 2 resulted in addition of three valine residues at codon 71 of the P450c21 protein. Molecular dynamics simulations revealed that the mutant exhibits a faster unfolding kinetics and an overall destabilization of the structure due to the triple valine insertion was also observed. CONCLUSION The novel 9-bp insertion in exon 2 of CYP21A2 genesignificantly lowers the structural stability of P450c21 thereby leading to the probable loss of its function.
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Affiliation(s)
- Sudhisha Dubey
- Department of Molecular Endocrinology, National Institute for Research in Reproductive Health, Indian Council of Medical Research, J M Street, Parel, Mumbai, Maharashtra, India
| | - Susan Idicula-Thomas
- Biomedical Informatics Centre of Indian Council of Medical Research, National Institute for Research in Reproductive Health, J M Street, Parel, Mumbai, Maharashtra, India
| | - Mohammad Anwaruddin
- Biomedical Informatics Centre of Indian Council of Medical Research, National Institute for Research in Reproductive Health, J M Street, Parel, Mumbai, Maharashtra, India
| | - Chinnaraj Saravanan
- Department of Molecular Endocrinology, National Institute for Research in Reproductive Health, Indian Council of Medical Research, J M Street, Parel, Mumbai, Maharashtra, India
| | - R Raveendra Varma
- Department of Pediatrics and Neonatology, Mother's Hospital Trissur, Kerala, India
| | - Anurupa Maitra
- Department of Molecular Endocrinology, National Institute for Research in Reproductive Health, Indian Council of Medical Research, J M Street, Parel, Mumbai, Maharashtra, India
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16
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Mavridou DAI, Stevens JM, Goddard AD, Willis AC, Ferguson SJ, Redfield C. Control of periplasmic interdomain thiol:disulfide exchange in the transmembrane oxidoreductase DsbD. J Biol Chem 2008; 284:3219-3226. [PMID: 19004826 PMCID: PMC2631958 DOI: 10.1074/jbc.m805963200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The bacterial protein DsbD transfers reductant from the cytoplasm to the
otherwise oxidizing environment of the periplasm. This reducing power is
required for several essential pathways, including disulfide bond formation
and cytochrome c maturation. DsbD includes a transmembrane domain
(tmDsbD) flanked by two globular periplasmic domains (nDsbD/cDsbD); each
contains a cysteine pair involved in electron transfer via a disulfide
exchange cascade. The final step in the cascade involves reduction of the
Cys103-Cys109 disulfide of nDsbD by Cys461 of
cDsbD. Here we show that a complex between the globular periplasmic domains is
trapped in vivo only when both are linked by tmDsbD. We have found
previously (Mavridou, D. A., Stevens, J. M., Ferguson, S. J.,
& Redfield, C. (2007) J. Mol. Biol.370
,643
-65817544440) that the attacking
cysteine (Cys461) in isolated cDsbD has a high
pKa value (10.5) that makes this thiol relatively
unreactive toward the target disulfide in nDsbD. Here we show using NMR that
active-site pKa values change significantly when cDsbD
forms a complex with nDsbD. This modulation of pKa values
is critical for the specificity and function of cDsbD. Uncomplexed cDsbD is a
poor nucleophile, allowing it to avoid nonspecific reoxidation; however, in
complex with nDsbD, the nucleophilicity of cDsbD increases permitting
reductant transfer. The observation of significant changes in active-site
pKa values upon complex formation has wider implications
for understanding reactivity in thiol:disulfide oxidoreductases.
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Affiliation(s)
- Despoina A I Mavridou
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Julie M Stevens
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Alan D Goddard
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Antony C Willis
- Medical Research Council Immunochemistry Unit, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Stuart J Ferguson
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.
| | - Christina Redfield
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.
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17
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Rouhier N, Koh CS, Gelhaye E, Corbier C, Favier F, Didierjean C, Jacquot JP. Redox based anti-oxidant systems in plants: Biochemical and structural analyses. Biochim Biophys Acta Gen Subj 2008; 1780:1249-60. [DOI: 10.1016/j.bbagen.2007.12.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Revised: 12/11/2007] [Accepted: 12/17/2007] [Indexed: 12/18/2022]
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18
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Maeda K, Hägglund P, Finnie C, Svensson B, Henriksen A. Crystal structures of barley thioredoxin h isoforms HvTrxh1 and HvTrxh2 reveal features involved in protein recognition and possibly in discriminating the isoform specificity. Protein Sci 2008; 17:1015-24. [PMID: 18424513 DOI: 10.1110/ps.083460308] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
H-type thioredoxins (Trxs) constitute a particularly large Trx sub-group in higher plants. Here, the crystal structures are determined for the two barley Trx h isoforms, HvTrxh1 and HvTrxh2, in the partially radiation-reduced state to resolutions of 1.7 A, and for HvTrxh2 in the oxidized state to 2.0 A. The two Trxs have a sequence identity of 51% and highly similar fold and active-site architecture. Interestingly, the four independent molecules in the crystals of HvTrxh1 form two relatively large and essentially identical protein-protein interfaces. In each interface, a loop segment of one HvTrxh1 molecule is positioned along a shallow hydrophobic groove at the primary nucleophile Cys40 of another HvTrxh1 molecule. The association mode can serve as a model for the target protein recognition by Trx, as it brings the Met82 Cgamma atom (gamma position as a disulfide sulfur) of the bound loop segment in the proximity of the Cys40 thiol. The interaction involves three characteristic backbone-backbone hydrogen bonds in an antiparallel beta-sheet-like arrangement, similar to the arrangement observed in the structure of an engineered, covalently bound complex between Trx and a substrate protein, as reported by Maeda et al. in an earlier paper. The occurrence of an intermolecular salt bridge between Glu80 of the bound loop segment and Arg101 near the hydrophobic groove suggests that charge complementarity plays a role in the specificity of Trx. In HvTrxh2, isoleucine corresponds to this arginine, which emphasizes the potential for specificity differences between the coexisting barley Trx isoforms.
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Affiliation(s)
- Kenji Maeda
- Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
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19
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Amorim GC, Pinheiro AS, Netto LES, Valente AP, Almeida FCL. NMR solution structure of the reduced form of thioredoxin 2 from Saccharomyces cerevisiae. JOURNAL OF BIOMOLECULAR NMR 2007; 38:99-104. [PMID: 17340205 DOI: 10.1007/s10858-007-9144-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 01/03/2007] [Accepted: 01/08/2007] [Indexed: 05/14/2023]
Affiliation(s)
- Gisele Cardoso Amorim
- Centro Nacional de Ressonância Magnética Nuclear-Instituto de Bioquímica Médica-CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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20
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Roos G, Garcia-Pino A, Van Belle K, Brosens E, Wahni K, Vandenbussche G, Wyns L, Loris R, Messens J. The Conserved Active Site Proline Determines the Reducing Power of Staphylococcus aureus Thioredoxin. J Mol Biol 2007; 368:800-11. [PMID: 17368484 DOI: 10.1016/j.jmb.2007.02.045] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 02/10/2007] [Accepted: 02/13/2007] [Indexed: 11/15/2022]
Abstract
Nature uses thioredoxin-like folds in several disulfide bond oxidoreductases. Each of them has a typical active site Cys-X-X-Cys sequence motif, the hallmark of thioredoxin being Trp-Cys-Gly-Pro-Cys. The intriguing role of the highly conserved proline in the ubiquitous reducing agent thioredoxin was studied by site-specific mutagenesis of Staphylococcus aureus thioredoxin (Sa_Trx). We present X-ray structures, redox potential, pK(a), steady-state kinetic parameters, and thermodynamic stabilities. By replacing the central proline to a threonine/serine, no extra hydrogen bonds with the sulphur of the nucleophilic cysteine are introduced. The only structural difference is that the immediate chemical surrounding of the nucleophilic cysteine becomes more hydrophilic. The pK(a) value of the nucleophilic cysteine decreases with approximately one pH unit and its redox potential increases with 30 mV. Thioredoxin becomes more oxidizing and the efficiency to catalyse substrate reduction (k(cat)/K(M)) decreases sevenfold relative to wild-type Sa_Trx. The oxidized form of wild-type Sa_Trx is far more stable than the reduced form over the whole temperature range. The driving force to reduce substrate proteins is the relative stability of the oxidized versus the reduced form Delta(T(1/2))(ox/red). This driving force is decreased in the Sa_Trx P31T mutant. Delta(T(1/2))(ox/red) drops from 15.5 degrees C (wild-type) to 5.8 degrees C (P31T mutant). In conclusion, the active site proline in thioredoxin determines the driving potential for substrate reduction.
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Affiliation(s)
- Goedele Roos
- Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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21
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Maeda K, Hägglund P, Finnie C, Svensson B, Henriksen A. Structural basis for target protein recognition by the protein disulfide reductase thioredoxin. Structure 2007; 14:1701-10. [PMID: 17098195 DOI: 10.1016/j.str.2006.09.012] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 09/21/2006] [Accepted: 09/24/2006] [Indexed: 10/23/2022]
Abstract
Thioredoxin is ubiquitous and regulates various target proteins through disulfide bond reduction. We report the structure of thioredoxin (HvTrxh2 from barley) in a reaction intermediate complex with a protein substrate, barley alpha-amylase/subtilisin inhibitor (BASI). The crystal structure of this mixed disulfide shows a conserved hydrophobic motif in thioredoxin interacting with a sequence of residues from BASI through van der Waals contacts and backbone-backbone hydrogen bonds. The observed structural complementarity suggests that the recognition of features around protein disulfides plays a major role in the specificity and protein disulfide reductase activity of thioredoxin. This novel insight into the function of thioredoxin constitutes a basis for comprehensive understanding of its biological role. Moreover, comparison with structurally related proteins shows that thioredoxin shares a mechanism with glutaredoxin and glutathione transferase for correctly positioning substrate cysteine residues at the catalytic groups but possesses a unique structural element that allows recognition of protein disulfides.
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Affiliation(s)
- Kenji Maeda
- Enzyme and Protein Chemistry, BioCentrum-DTU, Søltofts Plads, Building 224, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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22
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Limacher A, Glaser AG, Meier C, Schmid-Grendelmeier P, Zeller S, Scapozza L, Crameri R. Cross-reactivity and 1.4-A crystal structure of Malassezia sympodialis thioredoxin (Mala s 13), a member of a new pan-allergen family. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2007; 178:389-96. [PMID: 17182577 DOI: 10.4049/jimmunol.178.1.389] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have identified thioredoxins (Trx) of Malassezia sympodialis, a yeast involved in the pathogenesis of atopic eczema, and of Aspergillus fumigatus, a fungus involved in pulmonary complications, as novel IgE-binding proteins. We show that these Trx, including the human enzyme, represent cross-reactive structures recognized by serum IgE from individuals sensitized to M. sympodialis Trx. Moreover, all three proteins were able to elicit immediate-type allergic skin reactions in sensitized individuals, indicating a humoral immune response based on molecular mimicry. To analyze structural elements involved in these reactions, the three-dimensional structure of M. sympodialis Trx (Mala s 13) has been determined at 1.4-A resolution by x-ray diffraction analysis. The structure was solved by molecular replacement and refined to a crystallographic R factor of 14.0% and a free R factor of 16.8% and shows the typical Trx fold. Mala s 13 shares 45% sequence identity with human Trx and superposition of the solved Mala s 13 structure with those of human Trx reveals a high similarity with a root mean square deviation of 1.11 A for all Calpha atoms. In a detailed analysis of the molecular surface in combination with sequence alignment, we identified conserved solvent-exposed amino acids scattered over the surface in both structures which cluster to patches, thus forming putative conformational B cell epitopes potentially involved in IgE-mediated cross- and autoreactivity.
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Affiliation(s)
- Andreas Limacher
- Swiss Institute of Allergy and Asthma Research (SIAF), Davos, Switzerland
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23
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Tian G, Xiang S, Noiva R, Lennarz WJ, Schindelin H. The crystal structure of yeast protein disulfide isomerase suggests cooperativity between its active sites. Cell 2006; 124:61-73. [PMID: 16413482 DOI: 10.1016/j.cell.2005.10.044] [Citation(s) in RCA: 291] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 08/24/2005] [Accepted: 10/11/2005] [Indexed: 01/01/2023]
Abstract
Protein disulfide isomerase plays a key role in catalyzing the folding of secretory proteins. It features two catalytically inactive thioredoxin domains inserted between two catalytically active thioredoxin domains and an acidic C-terminal tail. The crystal structure of yeast PDI reveals that the four thioredoxin domains are arranged in the shape of a twisted "U" with the active sites facing each other across the long sides of the "U." The inside surface of the "U" is enriched in hydrophobic residues, thereby facilitating interactions with misfolded proteins. The domain arrangement, active site location, and surface features strikingly resemble the Escherichia coli DsbC and DsbG protein disulfide isomerases. Biochemical studies demonstrate that all domains of PDI, including the C-terminal tail, are required for full catalytic activity. The structure defines a framework for rationalizing the differences between the two active sites and their respective roles in catalyzing the formation and rearrangement of disulfide bonds.
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Affiliation(s)
- Geng Tian
- Department of Biochemistry and Cell Biology, State University of New York at Stony Brook, NY 11794, USA
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24
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Hisabori T, Motohashi K, Hosoya-Matsuda N, Ueoka-Nakanishi H, Romano PGN. Towards a Functional Dissection of Thioredoxin Networks in Plant Cells. Photochem Photobiol 2006; 83:145-51. [PMID: 16706599 DOI: 10.1562/2006-02-27-ir-816] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Thioredoxins are a ubiquitous family of redox equivalent mediators, long considered to possess a limited number of target enzymes. Recent progress in proteomic research has allowed the identification of a wide variety of candidate proteins with which this small protein may interact in vivo. Moreover, the activity of thioredoxin itself has been recently found to be subject to regulation by posttranslational modifications, adding an additional level of complexity to the function of this intriguing enzyme family. The current review charts the technical progress made in the continuing discovery of the numerous and diverse roles played by these proteins in the regulation of redox networks in plant cells.
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Affiliation(s)
- Toru Hisabori
- Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan.
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25
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Stefankova P, Maderova J, Barak I, Kollarova M, Otwinowski Z. Expression, purification and X-ray crystallographic analysis of thioredoxin from Streptomyces coelicolor. Acta Crystallogr Sect F Struct Biol Cryst Commun 2005; 61:164-8. [PMID: 16510983 PMCID: PMC1952260 DOI: 10.1107/s1744309104032993] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Accepted: 12/13/2004] [Indexed: 12/28/2022]
Abstract
Thioredoxins are ubiquitous proteins that serve as reducing agents and general protein disulfide reductases. In turn, they are reduced by electrons obtained from the NADPH-containing thioredoxin reductase. Thioredoxins have been isolated and characterized from a large number of organisms. The Gram-positive bacterium Streptomyces coelicolor contains three thioredoxins that are involved in unknown biological processes. trxA from S. coelicolor was cloned and expressed in Escherichia coli and the protein purified and crystallized using the hanging-drop method of vapour diffusion. The crystal structure of thioredoxin A has been determined at 1.5 A resolution using a synchrotron-radiation source. The protein reveals a thioredoxin-like fold with a typical CXXC active site. The crystal exhibits the symmetry of space group P2(1)2(1)2, with unit-cell parameters a = 43.6, b = 71.8, c = 33.2 A.
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Affiliation(s)
- Petra Stefankova
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynska dolina CH-1, 842 15 Bratislava, Slovak Republic
| | - Jana Maderova
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynska dolina CH-1, 842 15 Bratislava, Slovak Republic
- Department of Biochemistry, Southwestern Medical Center at Dallas, University of Texas, 5323 Harry Hines Boulevard, 75390 Dallas, Texas, USA
| | - Imrich Barak
- Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta, 845 51 Bratislava 45, Slovak Republic
| | - Marta Kollarova
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynska dolina CH-1, 842 15 Bratislava, Slovak Republic
| | - Zbyszek Otwinowski
- Department of Biochemistry, Southwestern Medical Center at Dallas, University of Texas, 5323 Harry Hines Boulevard, 75390 Dallas, Texas, USA
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Wahl MC, Irmler A, Hecker B, Schirmer RH, Becker K. Comparative structural analysis of oxidized and reduced thioredoxin from Drosophila melanogaster. J Mol Biol 2004; 345:1119-30. [PMID: 15644209 DOI: 10.1016/j.jmb.2004.11.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Revised: 11/01/2004] [Accepted: 11/02/2004] [Indexed: 10/26/2022]
Abstract
Thioredoxins (Trx) participate in essential antioxidant and redox-regulatory processes via a pair of conserved cysteine residues. In dipteran insects like Drosophila and Anopheles, which lack a genuine glutathione reductase (GR), thioredoxins fuel the glutathione system with reducing equivalents. Thus, characterizing Trxs from these organisms contributes to our understanding of redox control in GR-free systems and provides information on novel targets for insect control. Cytosolic Trx of Drosophila melanogaster (DmTrx) is the first thioredoxin that was crystallized for X-ray diffraction analysis in the reduced and in the oxidized form. Comparison of the resulting structures shows rearrangements in the active-site regions. Formation of the C32-C35 disulfide bridge leads to a rotation of the side-chain of C32 away from C35 in the reduced form. This is similar to the situation in human Trx and Trx m from spinach chloroplasts but differs from Escherichia coli Trx, where it is C35 that moves upon change of the redox state. In all four crystal forms that were analysed, DmTrx molecules are engaged in a non-covalent dimer interaction. However, as demonstrated by gel-filtration analyses, DmTrx does not dimerize under quasi in vivo conditions and there is no redox control of a putative monomer/dimer equilibrium. The dimer dissociation constants K(d) were found to be 2.2mM for reduced DmTrx and above 10mM for oxidized DmTrx as well as for the protein in the presence of reduced glutathione. In human Trx, oxidative dimerization has been demonstrated in vitro. Therefore, this finding may indicate a difference in redox control of GR-free and GR-containing organisms.
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Affiliation(s)
- Markus C Wahl
- Max-Planck-Institut für Biophysikalische Chemie, Arbeitsgruppe Röntgenkristallographie, Am Fassberg 11, D-37077 Göttingen, Germany.
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27
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Capitani G, Schürmann P. On the Quaternary Assembly of Spinach Chloroplast Thioredoxin m. PHOTOSYNTHESIS RESEARCH 2004; 79:281-5. [PMID: 16328794 DOI: 10.1023/b:pres.0000017197.03467.81] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Thioredoxin m from spinach chloroplast has been structurally characterized both by X-ray crystallography and by NMR. Thioredoxin m is known to be monomeric, a finding which is confirmed by the NMR results. The crystal structure of this protein, however, contains two independent molecules per asymmetric unit. This fact was interpreted as contrasting with the NMR results [Neira et al. (2001) Biochemistry 40: 15246-15256]. Based on computational and biochemical considerations, we show that the presence of two thioredoxin m molecules per asymmetric unit bears no biological significance and does not contrast with the NMR results. The non-covalent arrangement of two monomers found in the crystals represents a 'crystallization intermediate' formed under the conditions for crystal growth.
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Affiliation(s)
- Guido Capitani
- Biochemisches Institut, University of Zürich, 8057, Zürich, Switzerland
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28
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Maeda K, Finnie C, ØStergaard O, Svensson B. Identification, cloning and characterization of two thioredoxin h isoforms, HvTrxh1 and HvTrxh2, from the barley seed proteome. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:2633-43. [PMID: 12787030 DOI: 10.1046/j.1432-1033.2003.03637.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Two thioredoxin h isoforms, HvTrxh1 and HvTrxh2, were identified in two and one spots, respectively, in a proteome analysis of barley (Hordeum vulgare) seeds based on 2D gel electrophoresis and MS. HvTrxh1 was observed in 2D gel patterns of endosperm, aleurone layer and embryo of mature barley seeds, and HvTrxh2 was present mainly in the embryo. During germination, HvTrxh2 decreased in abundance and HvTrxh1 decreased in the aleurone layer and endosperm but remained at high levels in the embryo. On the basis of MS identification of the two isoforms, expressed sequence tag sequences were identified, and cDNAs encoding HvTrxh1 and HvTrxh2 were cloned by RT-PCR. The sequences were 51% identical, but showed higer similarity to thioredoxin h isoforms from other cereals, e.g. rice Trxh (74% identical with HvTrxh1) and wheat TrxTa (90% identical with HvTrxh2). Recombinant HvTrxh1, HvTrxh2 and TrxTa were produced in Escherichia coli and purified using a three-step procedure. The activity of the purified recombinant thioredoxin h isoforms was demonstrated using insulin and barley alpha-amylase/subtilisin inhibitor as substrates. HvTrxh1 and HvTrxh2 were also efficiently reduced by Arabidopsis thaliana NADP-dependent thioredoxin reductase (NTR). The biochemical properties of HvTrxh2 and TrxTa were similar, whereas HvTrxh1 had higher insulin-reducing activity and was a better substrate for Arabidopsis NTR than HvTrxh2, with a Km of 13 micro m compared with 44 micro m for HvTrxh2. Thus, barley seeds contain two distinct thioredoxin h isoforms which differ in temporal and spatial distribution and kinetic properties, suggesting that they may have different physiological roles.
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Affiliation(s)
- Kenji Maeda
- Department of Chemistry, Carlsberg Laboratory, Copenhagen, Denmark
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29
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Jacquot JP, Gelhaye E, Rouhier N, Corbier C, Didierjean C, Aubry A. Thioredoxins and related proteins in photosynthetic organisms: molecular basis for thiol dependent regulation. Biochem Pharmacol 2002; 64:1065-9. [PMID: 12213606 DOI: 10.1016/s0006-2952(02)01177-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Thioredoxins are small molecular weight disulfide oxidoreductases specialized in the reduction of disulfide bonds on other proteins. Generally, the enzymes which are selectively and reversibly reduced by these proteins oscillate between an oxidized and inactive conformation and a reduced and active conformation. Thioredoxin constitutes the archetype of a family of protein disulfide oxidoreductases which comprises glutaredoxin and protein disulfide isomerase. Thioredoxin and glutaredoxin serve many roles in the cell, including the redox regulation of target enzymes and transcription factors. They can also serve as hydrogen donors to peroxiredoxins, recently discovered heme free peroxidases, the function of which is to get rid of hydroperoxides in the cell. This review describes the molecular basis for the functioning and interaction between these enzymes in photosynthetic organisms.
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Affiliation(s)
- Jean-Pierre Jacquot
- UMR INRA UHP Interaction Arbres Microorganismes, Université Henri Poincaré, Vandoeuvre, France.
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