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Bernard Knoops - One of the best experts on this subject based on the ideXlab platform.
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The curious case of Peroxiredoxin-5: what its absence in aves can tell us and how it can be used
BMC Evolutionary Biology, 2018Co-Authors: Marc Pirson, André Clippe, Bernard KnoopsAbstract:Background Peroxiredoxins are ubiquitous thiol-dependent peroxidases that represent a major antioxidant defense in both prokaryotic cells and eukaryotic organisms. Among the six vertebrate Peroxiredoxin isoforms, Peroxiredoxin-5 (PRDX5) appears to be a particular Peroxiredoxin, displaying a different catalytic mechanism, as well as a wider substrate specificity and subcellular distribution. In addition, several evolutionary peculiarities, such as loss of subcellular targeting in certain species, have been reported for this enzyme. Results Western blotting analyses of 2-cys PRDXs (PRDX1–5) failed to identify the PRDX5 isoform in chicken tissue homogenates. Thereafter, via in silico analysis of PRDX5 orthologs, we went on to show that the PRDX5 gene is conserved in all branches of the amniotes clade, with the exception of aves. Further investigation of bird genomic sequences and expressed tag sequences confirmed the disappearance of the gene, though TRMT112 , a gene located closely to the 5′ extremity of the PRDX5 gene, is conserved. Finally, using in ovo electroporation to overexpress the long and short forms of human PRDX5, we showed that, though the gene is lost in birds, subcellular targeting of human PRDX5 is conserved in the chick. Conclusions Further adding to the distinctiveness of this enzyme, this study reports converging evidence supporting loss of PRDX5 in aves. In-depth analysis revealed that this absence is proper to birds as PRDX5 appears to be conserved in non-avian amniotes. Finally, taking advantage of the in ovo electroporation technique, we validate the subcellular targeting of human PRDX5 in the chick embryo and bring forward this gain-of-function model as a potent way to study PRDX5 functions in vivo.
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Multiple Roles of Peroxiredoxins in Inflammation
Molecules and cells, 2016Co-Authors: Bernard Knoops, Vasiliki Argyropoulou, Sarah Becker, Laura Ferté, Oksana KuznetsovaAbstract:Inflammation is a pathophysiological response to infection or tissue damage during which high levels of reactive oxygen and nitrogen species are produced by phagocytes to kill microorganisms. Reactive oxygen and nitrogen species serve also in the complex regulation of inflammatory processes. Recently, it has been proposed that Peroxiredoxins may play key roles in innate immunity and inflammation. Indeed, Peroxiredoxins are evolutionarily conserved peroxidases able to reduce, with high rate constants, hydrogen peroxide, alkyl hydroperoxides and peroxynitrite which are generated during inflammation. In this minireview, we point out different possible roles of Peroxiredoxins during inflammatory processes such as cytoprotective enzymes against oxidative stress, modulators of redox signaling, and extracellular pathogen- or damage-associated molecular patterns. A better understanding of Peroxiredoxin functions in inflammation could lead to the discovery of new therapeutic targets.
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Peroxiredoxin 5 structure mechanism and function of the mammalian atypical 2 cys Peroxiredoxin
Antioxidants & Redox Signaling, 2011Co-Authors: Bernard Knoops, Julie Goemaere, Valerie Van Der Eecken, Jeanpaul DeclercqAbstract:Peroxiredoxin 5 (PRDX5) was the last member to be identified among the six mammalian Peroxiredoxins. It is also the unique atypical 2-Cys Peroxiredoxin in mammals. Like the other five members, PRDX5 is widely expressed in tissues but differs by its surprisingly large subcellular distribution. In human cells, it has been shown that PRDX5 can be addressed to mitochondria, peroxisomes, the cytosol, and the nucleus. PRDX5 is a peroxidase that can use cytosolic or mitochondrial thioredoxins to reduce alkyl hydroperoxides or peroxynitrite with high rate constants in the 10(6) to 10(7) M(-1)s(-1) range, whereas its reaction with hydrogen peroxide is more modest, in the 10(5) M(-1)s(-1) range. PRDX5 crystal structures confirmed the proposed enzymatic mechanisms based on biochemical data but revealed also some specific unexpected structural features. So far, PRDX5 has been viewed mainly as a cytoprotective antioxidant enzyme acting against endogenous or exogenous peroxide attacks rather than as a redox sensor. Accordingly, overexpression of the enzyme in different subcellular compartments protects cells against death caused by nitro-oxidative stresses, whereas gene silencing makes them more vulnerable. Thus, more than 10 years after its molecular cloning, mammalian PRDX5 appears to be a unique Peroxiredoxin exhibiting specific functional and structural features.
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Discovery of fragment molecules that bind the human Peroxiredoxin 5 active site.
PloS one, 2010Co-Authors: Sarah Barelier, Jean-marc Lancelin, Bernard Knoops, André Clippe, Dominique Linard, Julien Pons, Isabelle KrimmAbstract:The search for protein ligands is a crucial step in the inhibitor design process. Fragment screening represents an interesting method to rapidly find lead molecules, as it enables the exploration of a larger portion of the chemical space with a smaller number of compounds as compared to screening based on drug-sized molecules. Moreover, fragment screening usually leads to hit molecules that form few but optimal interactions with the target, thus displaying high ligand efficiencies. Here we report the screening of a homemade library composed of 200 highly diverse fragments against the human Peroxiredoxin 5 protein. Peroxiredoxins compose a family of peroxidases that share the ability to reduce peroxides through a conserved cysteine. The three-dimensional structures of these enzymes ubiquitously found throughout evolution have been extensively studied, however, their biological functions are still not well understood and to date few inhibitors have been discovered against these enzymes. Six fragments from the library were shown to bind to the Peroxiredoxin 5 active site and ligand-induced chemical shift changes were used to drive the docking of these small molecules into the protein structure. The orientation of the fragments in the binding pocket was confirmed by the study of fragment homologues, highlighting the role of hydroxyl functions that hang the ligands to the Peroxiredoxin 5 protein. Among the hit fragments, the small catechol molecule was shown to significantly inhibit Peroxiredoxin 5 activity in a thioredoxin peroxidase assay. This study reports novel data about the ligand-Peroxiredoxin interactions that will help considerably the development of potential Peroxiredoxin inhibitors.
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Discovery of fragment molecules that bind the human Peroxiredoxin 5 active site. : Screening of human Peroxiredoxin 5.
PLOS ONE, 2010Co-Authors: Sarah Barelier, Jean-marc Lancelin, Bernard Knoops, André Clippe, Dominique Linard, Julien Pons, Isabelle KrimmAbstract:The search for protein ligands is a crucial step in the inhibitor design process. Fragment screening represents an interesting method to rapidly find lead molecules, as it enables the exploration of a larger portion of the chemical space with a smaller number of compounds as compared to screening based on drug-sized molecules. Moreover, fragment screening usually leads to hit molecules that form few but optimal interactions with the target, thus displaying high ligand efficiencies. Here we report the screening of a homemade library composed of 200 highly diverse fragments against the human Peroxiredoxin 5 protein. Peroxiredoxins compose a family of peroxidases that share the ability to reduce peroxides through a conserved cysteine. The three-dimensional structures of these enzymes ubiquitously found throughout evolution have been extensively studied, however, their biological functions are still not well understood and to date few inhibitors have been discovered against these enzymes. Six fragments from the library were shown to bind to the Peroxiredoxin 5 active site and ligand-induced chemical shift changes were used to drive the docking of these small molecules into the protein structure. The orientation of the fragments in the binding pocket was confirmed by the study of fragment homologues, highlighting the role of hydroxyl functions that hang the ligands to the Peroxiredoxin 5 protein. Among the hit fragments, the small catechol molecule was shown to significantly inhibit Peroxiredoxin 5 activity in a thioredoxin peroxidase assay. This study reports novel data about the ligand-Peroxiredoxin interactions that will help considerably the development of potential Peroxiredoxin inhibitors.
Jean-marc Lancelin - One of the best experts on this subject based on the ideXlab platform.
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Predicting and understanding the enzymatic inhibition of human Peroxiredoxin 5 by 4-substituted pyrocatechols by combining funnel metadynamics, solution NMR, and steady-state kinetics
Biochemistry, 2016Co-Authors: Mélissa Chow, Laura Troussicot, Marie Martin, Bastien Doumèche, Florence Guillière, Jean-marc LancelinAbstract:Funnel metadynamics is a kind of computational simulation used to enhance the sampling of protein ligand binding events in solution. By characterization of the binding interaction events, an estimated absolute binding free energy can be calculated. Nuclear magnetic resonance and funnel metadynamics were used to evaluate the binding of pyrocatechol derivatives (catechol, 4-methylcatechol, and 4-tert-butylcatechol) to human Peroxiredoxin 5. Human Peroxiredoxins are peroxidases involved in cellular peroxide homeostasis. Recently, overexpressed or suppressed Peroxiredoxin levels have been linked to various diseases. Here, the catechol derivatives were found to be inhibitors against human Peroxiredoxin 5 through a partial mixed type noncompetitive mechanism. Funnel metadynamics provided a microscopic model for interpreting the inhibition mechanism. Correlations were observed between the inhibition constants and the absolute binding free energy. Overall, this study showcases the fact that funnel metadynamics simulations can be employed as a preliminary approach to gain an in-depth understanding of potential enzyme inhibitors.
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Discovery of fragment molecules that bind the human Peroxiredoxin 5 active site.
PloS one, 2010Co-Authors: Sarah Barelier, Jean-marc Lancelin, Bernard Knoops, André Clippe, Dominique Linard, Julien Pons, Isabelle KrimmAbstract:The search for protein ligands is a crucial step in the inhibitor design process. Fragment screening represents an interesting method to rapidly find lead molecules, as it enables the exploration of a larger portion of the chemical space with a smaller number of compounds as compared to screening based on drug-sized molecules. Moreover, fragment screening usually leads to hit molecules that form few but optimal interactions with the target, thus displaying high ligand efficiencies. Here we report the screening of a homemade library composed of 200 highly diverse fragments against the human Peroxiredoxin 5 protein. Peroxiredoxins compose a family of peroxidases that share the ability to reduce peroxides through a conserved cysteine. The three-dimensional structures of these enzymes ubiquitously found throughout evolution have been extensively studied, however, their biological functions are still not well understood and to date few inhibitors have been discovered against these enzymes. Six fragments from the library were shown to bind to the Peroxiredoxin 5 active site and ligand-induced chemical shift changes were used to drive the docking of these small molecules into the protein structure. The orientation of the fragments in the binding pocket was confirmed by the study of fragment homologues, highlighting the role of hydroxyl functions that hang the ligands to the Peroxiredoxin 5 protein. Among the hit fragments, the small catechol molecule was shown to significantly inhibit Peroxiredoxin 5 activity in a thioredoxin peroxidase assay. This study reports novel data about the ligand-Peroxiredoxin interactions that will help considerably the development of potential Peroxiredoxin inhibitors.
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Discovery of fragment molecules that bind the human Peroxiredoxin 5 active site. : Screening of human Peroxiredoxin 5.
PLOS ONE, 2010Co-Authors: Sarah Barelier, Jean-marc Lancelin, Bernard Knoops, André Clippe, Dominique Linard, Julien Pons, Isabelle KrimmAbstract:The search for protein ligands is a crucial step in the inhibitor design process. Fragment screening represents an interesting method to rapidly find lead molecules, as it enables the exploration of a larger portion of the chemical space with a smaller number of compounds as compared to screening based on drug-sized molecules. Moreover, fragment screening usually leads to hit molecules that form few but optimal interactions with the target, thus displaying high ligand efficiencies. Here we report the screening of a homemade library composed of 200 highly diverse fragments against the human Peroxiredoxin 5 protein. Peroxiredoxins compose a family of peroxidases that share the ability to reduce peroxides through a conserved cysteine. The three-dimensional structures of these enzymes ubiquitously found throughout evolution have been extensively studied, however, their biological functions are still not well understood and to date few inhibitors have been discovered against these enzymes. Six fragments from the library were shown to bind to the Peroxiredoxin 5 active site and ligand-induced chemical shift changes were used to drive the docking of these small molecules into the protein structure. The orientation of the fragments in the binding pocket was confirmed by the study of fragment homologues, highlighting the role of hydroxyl functions that hang the ligands to the Peroxiredoxin 5 protein. Among the hit fragments, the small catechol molecule was shown to significantly inhibit Peroxiredoxin 5 activity in a thioredoxin peroxidase assay. This study reports novel data about the ligand-Peroxiredoxin interactions that will help considerably the development of potential Peroxiredoxin inhibitors.
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Protein-protein interactions within Peroxiredoxin systems.
Photosynthesis research, 2006Co-Authors: Valérie Noguera-mazon, Isabelle Krimm, Olivier Walker, Jean-marc LancelinAbstract:Peroxiredoxin systems in plants were demonstrated involved in crucial roles related to reactive oxygenated species (ROS) metabolism and the linked cell signalling to ROS. Peroxiredoxins function as peroxidasic systems that combine at least a reactivating reductant agent like thioredoxins, and sometimes glutaredoxins and glutathion. In the past three years a number of Peroxiredoxin structures were solved by crystallography in different experimental crystallisation conditions. The structures have revealed a significant propensity of Peroxiredoxins for oligomerism that was confirmed by biophysical studies in solution using NMR and other methods as analytical ultra-centrifugation. These studies showed that quaternary structures of Peroxiredoxins involve specific protein-protein interaction interfaces that rely upon the Peroxiredoxin types and/or their redox conditions. The protein-protein interactions with the reactivating redoxins essentially lead to transient unstable complexes. We review herein the different protein-protein interactions characterized or deduced from those reports.
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Protein–protein interactions within Peroxiredoxin systems
Photosynthesis Research, 2006Co-Authors: Valérie Noguera-mazon, Isabelle Krimm, Olivier Walker, Jean-marc LancelinAbstract:Peroxiredoxin systems in plants were demonstrated involved in crucial roles related to reactive oxygenated species (ROS) metabolism and the linked cell signalling to ROS. Peroxiredoxins function as peroxidasic systems that combine at least a reactivating reductant agent like thioredoxins, and sometimes glutaredoxins and glutathion. In the past three years a number of Peroxiredoxin structures were solved by crystallography in different experimental crystallisation conditions. The structures have revealed a significant propensity of Peroxiredoxins for oligomerism that was confirmed by biophysical studies in solution using NMR and other methods as analytical ultra-centrifugation. These studies showed that quaternary structures of Peroxiredoxins involve specific protein–protein interaction interfaces that rely upon the Peroxiredoxin types and/or their redox conditions. The protein–protein interactions with the reactivating redoxins essentially lead to transient unstable complexes. We review herein the different protein–protein interactions characterized or deduced from those reports.
Isabelle Krimm - One of the best experts on this subject based on the ideXlab platform.
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Discovery of fragment molecules that bind the human Peroxiredoxin 5 active site.
PloS one, 2010Co-Authors: Sarah Barelier, Jean-marc Lancelin, Bernard Knoops, André Clippe, Dominique Linard, Julien Pons, Isabelle KrimmAbstract:The search for protein ligands is a crucial step in the inhibitor design process. Fragment screening represents an interesting method to rapidly find lead molecules, as it enables the exploration of a larger portion of the chemical space with a smaller number of compounds as compared to screening based on drug-sized molecules. Moreover, fragment screening usually leads to hit molecules that form few but optimal interactions with the target, thus displaying high ligand efficiencies. Here we report the screening of a homemade library composed of 200 highly diverse fragments against the human Peroxiredoxin 5 protein. Peroxiredoxins compose a family of peroxidases that share the ability to reduce peroxides through a conserved cysteine. The three-dimensional structures of these enzymes ubiquitously found throughout evolution have been extensively studied, however, their biological functions are still not well understood and to date few inhibitors have been discovered against these enzymes. Six fragments from the library were shown to bind to the Peroxiredoxin 5 active site and ligand-induced chemical shift changes were used to drive the docking of these small molecules into the protein structure. The orientation of the fragments in the binding pocket was confirmed by the study of fragment homologues, highlighting the role of hydroxyl functions that hang the ligands to the Peroxiredoxin 5 protein. Among the hit fragments, the small catechol molecule was shown to significantly inhibit Peroxiredoxin 5 activity in a thioredoxin peroxidase assay. This study reports novel data about the ligand-Peroxiredoxin interactions that will help considerably the development of potential Peroxiredoxin inhibitors.
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Discovery of fragment molecules that bind the human Peroxiredoxin 5 active site. : Screening of human Peroxiredoxin 5.
PLOS ONE, 2010Co-Authors: Sarah Barelier, Jean-marc Lancelin, Bernard Knoops, André Clippe, Dominique Linard, Julien Pons, Isabelle KrimmAbstract:The search for protein ligands is a crucial step in the inhibitor design process. Fragment screening represents an interesting method to rapidly find lead molecules, as it enables the exploration of a larger portion of the chemical space with a smaller number of compounds as compared to screening based on drug-sized molecules. Moreover, fragment screening usually leads to hit molecules that form few but optimal interactions with the target, thus displaying high ligand efficiencies. Here we report the screening of a homemade library composed of 200 highly diverse fragments against the human Peroxiredoxin 5 protein. Peroxiredoxins compose a family of peroxidases that share the ability to reduce peroxides through a conserved cysteine. The three-dimensional structures of these enzymes ubiquitously found throughout evolution have been extensively studied, however, their biological functions are still not well understood and to date few inhibitors have been discovered against these enzymes. Six fragments from the library were shown to bind to the Peroxiredoxin 5 active site and ligand-induced chemical shift changes were used to drive the docking of these small molecules into the protein structure. The orientation of the fragments in the binding pocket was confirmed by the study of fragment homologues, highlighting the role of hydroxyl functions that hang the ligands to the Peroxiredoxin 5 protein. Among the hit fragments, the small catechol molecule was shown to significantly inhibit Peroxiredoxin 5 activity in a thioredoxin peroxidase assay. This study reports novel data about the ligand-Peroxiredoxin interactions that will help considerably the development of potential Peroxiredoxin inhibitors.
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Protein-protein interactions within Peroxiredoxin systems.
Photosynthesis research, 2006Co-Authors: Valérie Noguera-mazon, Isabelle Krimm, Olivier Walker, Jean-marc LancelinAbstract:Peroxiredoxin systems in plants were demonstrated involved in crucial roles related to reactive oxygenated species (ROS) metabolism and the linked cell signalling to ROS. Peroxiredoxins function as peroxidasic systems that combine at least a reactivating reductant agent like thioredoxins, and sometimes glutaredoxins and glutathion. In the past three years a number of Peroxiredoxin structures were solved by crystallography in different experimental crystallisation conditions. The structures have revealed a significant propensity of Peroxiredoxins for oligomerism that was confirmed by biophysical studies in solution using NMR and other methods as analytical ultra-centrifugation. These studies showed that quaternary structures of Peroxiredoxins involve specific protein-protein interaction interfaces that rely upon the Peroxiredoxin types and/or their redox conditions. The protein-protein interactions with the reactivating redoxins essentially lead to transient unstable complexes. We review herein the different protein-protein interactions characterized or deduced from those reports.
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Protein–protein interactions within Peroxiredoxin systems
Photosynthesis Research, 2006Co-Authors: Valérie Noguera-mazon, Isabelle Krimm, Olivier Walker, Jean-marc LancelinAbstract:Peroxiredoxin systems in plants were demonstrated involved in crucial roles related to reactive oxygenated species (ROS) metabolism and the linked cell signalling to ROS. Peroxiredoxins function as peroxidasic systems that combine at least a reactivating reductant agent like thioredoxins, and sometimes glutaredoxins and glutathion. In the past three years a number of Peroxiredoxin structures were solved by crystallography in different experimental crystallisation conditions. The structures have revealed a significant propensity of Peroxiredoxins for oligomerism that was confirmed by biophysical studies in solution using NMR and other methods as analytical ultra-centrifugation. These studies showed that quaternary structures of Peroxiredoxins involve specific protein–protein interaction interfaces that rely upon the Peroxiredoxin types and/or their redox conditions. The protein–protein interactions with the reactivating redoxins essentially lead to transient unstable complexes. We review herein the different protein–protein interactions characterized or deduced from those reports.
Karljosef Dietz - One of the best experts on this subject based on the ideXlab platform.
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Peroxiredoxins in plants and cyanobacteria
Antioxidants & Redox Signaling, 2011Co-Authors: Karljosef DietzAbstract:I. Introduction II. Classification of Plant Prxs and Their Distribution in Plants and Cyanobacteria III. Peroxidase Activity of Peroxiredoxins IV. Conformational Dynamics and Interacting Partners of Prx In Vitro and In Vivo V. Typical 2-Cys Peroxiredoxins A. Characteristics of 2-CysPrxs B. Reduction of oxidized 2-CysPrx C. Consequences of 2-CysPrx deficiency VI. Peroxiredoxin Q, an Atypical 2-CysPrx of Chloroplasts and Cyanobacteria VII. 1-Cysteine Peroxiredoxin VIII. Type II Peroxiredoxins, the Most Widely Distributed Atypical 2-CysPrxs in Plants A. Principle features of type II Prx B. Cytosolic PrxII C. Plastid PrxIIE D. Mitochondrial PrxIIF E. Cyanobacterial type II Prx IX. Plant Glutathione Peroxidases X. Posttranslational Regulation of Peroxiredoxin Activities A. Hyperoxidation and sulfiredoxin B. Nitrosylation C. Other posttranslational Prx modifications XI. Role of Peroxiredoxins in Plant Metabolism A. Plastids and photosynthesis B. Mitochondria and respiration XII. Peroxiredoxins as Chaperone and ...
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Thermodynamics of 2-Cys Peroxiredoxin assembly determined by isothermal titration calorimetry.
Methods in enzymology, 2009Co-Authors: Sergio Barranco-medina, Karljosef DietzAbstract:Oligomerization is a frequently encountered physical characteristic of biological molecules that occurs for a wide number of transcription factors, ion channels, oxygen-carrying macromolecules such as hemocyanin and enzymes. On the other hand, unwanted protein oligomerization can lead to the formation of pathogenic structures related with Alzheimer and other diseases. Self-assembly is also a well-described phenomenon within Peroxiredoxins, a family of thiol peroxidases. Peroxiredoxin hyperaggregate formation is the key mechanism that triggers the switch between Prx activity as peroxidase and chaperone. The oligomerization process is fundamental for understanding the multiple Peroxiredoxin function. The chapter gives a detailed description of typical 2-Cys Peroxiredoxin oligomerization using isothermal titration calorimetry (ITC) and provides a recipe for studying the thermodynamic parameters of Peroxiredoxin assembly, that is, association and dissociation constant, enthalpy, entropy, and the Gibbs free energy of the process.
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the function of the chloroplast 2 cysteine Peroxiredoxin in peroxide detoxification and its regulation
Journal of Experimental Botany, 2002Co-Authors: Karljosef Dietz, Frank Horling, Janine König, Margarete BaierAbstract:The Arabidopsis genome contains nine open reading frames with homology to members of the Peroxiredoxin (prx) family: one 1-Cys-prx, two 2-Cys-prx, five type II-prx, and one Peroxiredoxin Q. The function of the Peroxiredoxins in plant metabolism is only slowly emerging. They are assumed to reduce toxic peroxides to their corresponding alcohols with a rather broad substrate specificity. The 2-Cys Peroxiredoxins (2-CP) were recently identified as members of the antioxidant defence system of chloroplasts. Knock-out mutants of Synechocystis and antisense mutants of Arabidopsis have provided insight into the function of 2-CPs in the photosynthetic antioxidant network. This review summarizes present knowledge on the enzymatic mechanism, the physiological context and the genetic regulation of the 2-CPs in plants and cyanobacteria. In addition, an extrapolation on the metabolic role of the chloroplast 2-CP is attempted based on the molecular features of 2-CPs from other organisms.
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Type II Peroxiredoxin C, a member of the Peroxiredoxin family of Arabidopsis thaliana: its expression and activity in comparison with other Peroxiredoxins
Plant Physiology and Biochemistry, 2002Co-Authors: Frank Horling, Janine König, Karljosef DietzAbstract:Horling F, König J, Dietz K-J. Type II Peroxiredoxin C, a member of the Peroxiredoxin family of Arabidopsis thaliana: its expression and activity in comparison with other Peroxiredoxins. PLANT PHYSIOLOGY AND BIOCHEMISTRY. 2002;40(6-8):491-499
Mark B Hampton - One of the best experts on this subject based on the ideXlab platform.
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Quaternary structure influences the peroxidase activity of Peroxiredoxin 3.
Biochemical and biophysical research communications, 2018Co-Authors: N. Amy Yewdall, Alexander V. Peskin, Mark B Hampton, David C. Goldstone, F. Grant Pearce, Juliet A. GerrardAbstract:Peroxiredoxins are abundant peroxidase enzymes that are key regulators of the cellular redox environment. A major subgroup of these proteins, the typical 2-Cys Peroxiredoxins, can switch between dimers and decameric or dodecameric rings, during the catalytic cycle. The necessity of this change in quaternary structure for function as a peroxidase is not fully understood. In order to explore this, human Peroxiredoxin 3 (Prx3) protein was engineered to form both obligate dimers (S75E Prx3) and stabilised dodecameric rings (S78C Prx3), uncoupling structural transformations from the catalytic cycle. The obligate dimer, S75E Prx3, retained catalytic activity towards hydrogen peroxide, albeit significantly lower than the wildtype and S78C proteins, suggesting an evolutionary advantage of having higher order self-assemblies.
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Peroxiredoxin Involvement in the Initiation and Progression of Human Cancer.
Antioxidants & redox signaling, 2018Co-Authors: Mark B Hampton, Kate A Vick, John J. Skoko, Carola A. NeumannAbstract:Abstract Significance: It has been proposed that cancer cells are heavily dependent on their antioxidant defenses for survival and growth. Peroxiredoxins are a family of abundant thiol-dependent peroxidases that break down hydrogen peroxide, and they have a central role in the maintenance and response of cells to alterations in redox homeostasis. As such, they are potential targets for disrupting tumor growth. Recent Advances: Genetic disruption of Peroxiredoxin expression in mice leads to an increased incidence of neoplastic disease, consistent with a role for Peroxiredoxins in protecting genomic integrity. In contrast, many human tumors display increased levels of Peroxiredoxin expression, suggesting that strengthened antioxidant defenses provide a survival advantage for tumor progression. Peroxiredoxin inhibitors are being developed and explored as therapeutic agents in different cancer models. Critical Issues: It is important to complement Peroxiredoxin knockout and expression studies with an improved...
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Structures of Human Peroxiredoxin 3 Suggest Self-Chaperoning Assembly that Maintains Catalytic State.
Structure (London England : 1993), 2016Co-Authors: N. Amy Yewdall, Mark B Hampton, Alok K. Mitra, Juliet A. Gerrard, David C. Goldstone, Hariprasad Venugopal, Ambroise Desfosses, Vahid Abrishami, Yuliana Yosaatmadja, Mazdak RadjainiaAbstract:Peroxiredoxins are antioxidant proteins primarily responsible for detoxification of hydroperoxides in cells. On exposure to various cellular stresses, Peroxiredoxins can acquire chaperone activity, manifested as quaternary reorganization into a high molecular weight (HMW) form. Acidification, for example, causes dodecameric rings of human Peroxiredoxin 3 (HsPrx3) to stack into long helical filaments. In this work, a 4.1-A resolution structure of low-pH-instigated helical filaments was elucidated, showing a locally unfolded active site and partially folded C terminus. A 2.8-A crystal structure of HsPrx3 was determined at pH 8.5 under reducing conditions, wherein dodecameric rings are arranged as a short stack, with symmetry similar to low-pH filaments. In contrast to previous observations, the crystal structure displays both a fully folded active site and ordered C terminus, suggesting that the HsPrx3 HMW form maintains catalytic activity. We propose a new role for the HMW form as a self-chaperoning assembly maintaining HsPrx3 function under stress.
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Reversible oxidation of mitochondrial Peroxiredoxin 3 in mouse heart subjected to ischemia and reperfusion
FEBS letters, 2009Co-Authors: Vikas Kumar, Mark B Hampton, Nailya Kitaeff, Mark B. Cannell, Christine C WinterbournAbstract:Peroxiredoxins decompose peroxides through reversible oxidation of their active site cysteines. The redox state of the 2-Cys Peroxiredoxins, 1, 2 and 3, was investigated in mouse hearts undergoing ischemia and reperfusion in a Langendorff system. The Peroxiredoxins were predominantly reduced in control hearts. Mitochondrial Peroxiredoxin 3 underwent significant oxidation to its disulfide-linked dimer during ischemia. Oxidation was largely reversed during reperfusion. No redox changes in cytoplasmic Peroxiredoxins 1 and 2 were apparent. Peroxiredoxin 3 oxidation suggests localized mitochondrial generation of reactive oxidants during ischemia. This local antioxidant activity of Peroxiredoxin 3 may have a role in maintaining cardiac function.
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Oxidation of mitochondrial Peroxiredoxin 3 during the initiation of receptor-mediated apoptosis
Free radical biology & medicine, 2007Co-Authors: Andrew G Cox, Elizabeth C. Ledgerwood, Juliet M. Pullar, Gillian Hughes, Mark B HamptonAbstract:Abstract It is hypothesized that activation of death receptors disrupts the redox homeostasis of cells and that this contributes to the induction of apoptosis. The redox status of the Peroxiredoxins, which are extremely sensitive to increases in H2O2 and disruption of the thioredoxin system, were monitored in Jurkat T lymphoma cells undergoing Fas-mediated apoptosis. The only detectable change during the early stages of apoptosis was oxidation of mitochondrial Peroxiredoxin 3. Increased H2O2 triggers Peroxiredoxin overoxidation to a sulphinic acid; however during apoptosis Peroxiredoxin 3 was captured as a disulfide, suggesting impairment of the thioredoxin system responsible for maintaining Peroxiredoxin 3 in its reduced form. Peroxiredoxin 3 oxidation was an early event, occurring within the same timeframe as increased mitochondrial oxidant production, caspase activation and cytochrome c release. It preceded other major apoptotic events including mitochondrial permeability transition and phosphatidylserine exposure, and glutathione depletion, global thiol protein oxidation and protein carbonylation. Peroxiredoxin 3 oxidation was also observed in U937 cells stimulated with TNF-α. We hypothesize that the selective oxidation of Peroxiredoxin 3 leads to an increase in mitochondrial H2O2 and that this may influence the progression of apoptosis.
