DOCSLIB.ORG

Characterization of the Membrane-Bound Full-Length Complex Between Cytochrome B5 and Cytochrome P450

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Characterization of the Membrane-Bound Full-Length Complex Between Cytochrome B5 and Cytochrome P450 Characterization of the membrane-bound full-length complex between cytochrome b5 and cytochrome P450 2B4 by Stéphanie Valérie Le Clair A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Chemistry) in the University of Michigan 2013 Doctoral Committee: Professor Ayyalusamy Ramamoorthy, Chair Professor Michael Morris Professor Kristina Håkansson Assistant Professor Akira Ono © Stéphanie Valérie Le Clair 2013 DEDICATION To the Ramslab family ii ACKNOWLEDGEMENTS I would like to thank John, Sylvia and all other invaluable staff at C.H. – they saved my life in more ways than one. Thank you to Shani, Denise, Gustavo and Kevin for being essential parts of both my support system and my life – I would not have made it through graduate school without them. I would also like to thank Myron Campbell for believing me and taking my situation seriously. Importantly, I would like to thank Rams – he has really supported me throughout this graduate school journey. I am forever grateful to him for his kindness and support, and for giving me the room to grow as a scientist and a person. He has been the greatest sponsor for which I could have ever asked. Like any relationships, there were ups and downs, but through it all, I always knew that Rams had good intentions and wanted what was best for me. Thank you, Rams. I would like to thank the Rams Lab members – I consider all of them family. They were all such wonderful coworkers and made graduate school so much fun (we have pictures to prove it!). Special thanks to Neil for being so dedicated to teaching all of us the theory behind NMR. Thank you to Kevin for always listening, exploring U of M buildings and for pulling me through both the fun and hard times of graduate school. Thank you to Kazu for all the laughs and for paying me visits when we both stayed late iii in the lab. Thank you to Ron for being an older brother to me and continuing to support me even after leaving the lab. Thank you to Ron also for starting all the Rams lab traditions (the last supper, the birthday tradition and recess) and for creating a new kind of atmosphere in the lab. Thank you to both Ron and Pieter for all the inside jokes and for being a continuous source of laughter (the videos still make me laugh). Thank you to Vivek for always being willing to teach me about structure determination. Thank you to Shivani for teaching me how to prepare NMR samples, run NMR experiments and run HADDOCK simulations. Thank you to Meng for reminding me why I love science, for making research fun again and for keeping me company on late nights when I was working on my thesis in the office. Thank you to Nicole for the dance party and all the silliness. Thank you to the entire Cytochrome Team for stimulating scientific discussions both in group meetings and every day. Thank you to each member of the Rams lab – I always knew that I could talk to each one of them about any research obstacle I encountered. Thank you to my parents who allowed me to obtain an excellent undergraduate education. Thank you to all my professors at St. Mary’s who made me love science and who are great mentors and friends, even to this day. Thank you to SAPAC, OSCR and the Dean of Students Advisory Board for giving additional opportunities to grow as a person. Thank you to the SAPAC and OSCR staff for being so caring, encouraging and always being willing to meet with me and field any of my questions. iv TABLE OF CONTENTS DEDICATION........................................................................................................................ii ACKNOWLEDGMENTS.......................................................................................................iii LIST OF TABLES...................................................................................................................xi LIST OF FIGURES...............................................................................................................xiv LIST OF APPENDICES.........................................................................................................xx LIST OF ABBREVIATIONS..................................................................................................xxi CHAPTER 1 - Introduction: Biological background ............................................................ 1 1.1 Cytochrome b5 (cyt b5) .............................................................................................. 1 1.1.1 Cyt b5 background .............................................................................................. 1 1.1.2 Cyt b5 significance .............................................................................................. 4 1.1.3 Cyt b5 and its promiscuous association with numerous redox partners ........... 5 1.1.4 Rabbit cyt b5 ....................................................................................................... 7 1.2 Cytochrome P450 (cyt P450) .................................................................................. 11 1.2.1 Background and significance ........................................................................... 11 1.2.2 Structure and membrane topology of rabbit cyt P450 2B4 ............................ 13 1.3 The role of cyt b5 in cyt P450 reactions .................................................................. 20 1.4 Redox partner association theories ........................................................................ 31 1.5 Isotropic bicelles as a model membrane ................................................................ 33 1.5.1 DMPC/DHPC isotropic bicelles ......................................................................... 35 1.6 Goals of this research and dissertation layout ....................................................... 39 1.7 References .............................................................................................................. 40 CHAPTER 2 - Experimental methods for studying protein-protein complexes ............. 78 2.1 Site-directed mutagenesis and double mutant cycle analysis ............................... 78 v 2.2 1H-15N-TROSY-HSQC spectra for the study of large proteins .................................. 81 2.3 NMR chemical shift perturbation analysis .............................................................. 83 2.4 NMR differential line broadening analysis ............................................................. 85 2.5 High Ambiguity Driven biomolecular DOCKing (HADDOCK) ................................... 86 2.5.1 Ambiguous Interaction Restraints (AIRs) ......................................................... 87 2.5.2. Unambiguous restraints.................................................................................. 88 2.6 References .............................................................................................................. 89 CHAPTER 3 - Structure and dynamics of full-length cytochrome b5 .............................. 96 3.1 Summary ................................................................................................................. 96 3.2 Introduction ............................................................................................................ 97 3.3 Materials and methods ........................................................................................... 99 3.3.1 Materials .......................................................................................................... 99 3.3.2 Protein production and purification .............................................................. 100 3.3.3 Solution NMR spectroscopy ........................................................................... 101 3.3.3.1 Sequence specific assignment and structural determination ................ 101 3.3.3.2 Backbone 15N relaxation measurements ................................................ 102 3.3.4 TENSOR2 analysis ........................................................................................... 104 3.3.5 Structure determination of the cyt b5 soluble domain ................................. 104 3.3.6 Solid-state NMR spectroscopy ....................................................................... 105 3.3.7 Docking of heme into the cyt b5 NMR structure ........................................... 106 3.4 Results ................................................................................................................... 107 3.4.1 Sequence specific assignment of cyt b5 ......................................................... 107 3.4.2 Three-dimensional tertiary structure calculation of the soluble domain of full- length cyt b5 ............................................................................................................ 116 3.4.3 Backbone relaxation measurements ............................................................. 127 3.4.4 The structure of the soluble domain of cyt b5 is unaffected by its membrane environment ........................................................................................................... 131 3.4.5 Establishing the topology and structure of the transmembrane domain of full- length cyt b5 in bicelles ........................................................................................... 136 vi 3.5 Discussion .............................................................................................................. 137 3.6 Conclusion ............................................................................................................. 143
Load more

Recommended publications
  • Table S4. List of Enzymes Directly Involved in the Anti-Oxidant Defense Response
    Table S4. List of Enzymes directly involved in the anti-oxidant defense response. Gene Name Gene Symbol Classification/Pathway 6-phosphogluconate dehydrogenase 6PGD NADPH regeneration/Pentose Phosphate Glucose-6-phosphate dehydrogenase G6PD NADPH regeneration/Pentose Phosphate Isocitrate Dehydrogenase 1 IDH1 NADPH regeneration/Krebs Isocitrate Dehydrogenase 2 IDH2 NADPH regeneration/Krebs Malic Enzyme 1 ME1 NADPH regeneration/Krebs Methylenetetrahydrofolate dehydrogenase 1 MTHFD1 NADPH regeneration/Folate Methylenetetrahydrofolate dehydrogenase 2 MTHFD2 NADPH regeneration/Folate Nicotinamide Nucleotide Transhydrogenase NNT NADPH regeneration/NAD Catalase CAT Antioxidants/Catalses/free radical detoxification Glutamate-cysteine ligase catalytic subunit GCLC Antioxidants/Glutathione synthesis Glutamate-cysteine ligase modifier subunit GCLM Antioxidants/Glutathione synthesis Glutathione peroxidase1 GPx1 Antioxidants/Glutathione Peroxidases/free radical detoxification Glutathione peroxidase2 GPx2 Antioxidants/Glutathione Peroxidases/free radical detoxification Glutathione peroxidase3 GPx3 Antioxidants/Glutathione Peroxidases/free radical detoxification Glutathione peroxidase4 GPx4 Antioxidants/Glutathione Peroxidases/free radical detoxification Glutathione peroxidase5 GPx5 Antioxidants/Glutathione Peroxidases/free radical detoxification Glutathione peroxidase6 GPx6 Antioxidants/Glutathione Peroxidases/free radical detoxification Glutathione peroxidase7 GPx7 Antioxidants/Glutathione Peroxidases/free radical detoxification Glutathione S-transferase
    [Show full text]
  • Inhibitory Effects of Some Flavonoids on Thioredoxin Reductase Purified from Chicken Liver ABSTRACT INTRODUCTION
    Brazilian Journal of Poultry Science Revista Brasileira de Ciência Avícola Inhibitory Effects of Some Flavonoids on ISSN 1516-635X 2019 / v.21 / n.2 / 001-008 Thioredoxin Reductase Purified from Chicken http://dx.doi.org/10.1590/1806-9061-2018-0982 Liver Original Article Author(s) ABSTRACT Türkoğlu E.AI https://orcid.org/0000-0001-7850-6456 Thioredoxin reductases (TrxRs) are selenocysteine-containing Kuzu MII https://orcid.org/0000-0002-1375-7673 flavoenzymes that reduce Trxin NADPH-dependent manner. In the Ayasan TIII https://orcid.org/0000-0001-7397-6483 view of the direct vital role of TrxR in a wide range of biochemical and IV Inci H https://orcid.org/0000-0002-9791-0435 physiological processes, methods to inhibit this enzyme are clinically Eratak SVV https://orcid.org/0000-0003-3788-8704 important. TrxR has recently emerged as a new candidate in anticancer I Department of Pharmaceutical Biotechnology, drug investigations because of overexpression in tumorous cells. In this Faculty of Pharmacy, University of Health Sciences, Istanbul 34668, Turkey. study, TrxR from chick liver was purified 94.6-fold with a yield of 4.86% II Deparment of Chemistry, Faculty of Science and a specific activity of 0.19 EU/mg. K and V values of TrxR for and Letters, Ağrı İbrahim Çeçen University, Ağrı M max 04100, Turkey. DTNB were calculated as 0.9 mM and 0,03 EU/mL, respectively. Then, III East Mediterranean Agricultural Research Institute, Karatas Road, Adana 01321, Turkey. the effects of the flavonoids hesperidin, naringenin, chlorogenic acid, IV Department of Animal Science, Faculty of ferulic acid, naringin, 3,4-dihydoxybenzoic acid, and ellagic acid on the Agriculture, Bingöl University, Bingöl 12000, Turkey.
    [Show full text]
  • Genomic Insights Into the Uncultured Genus &Lsquo
    The ISME Journal (2014) 8, 2463–2477 & 2014 International Society for Microbial Ecology All rights reserved 1751-7362/14 www.nature.com/ismej ORIGINAL ARTICLE Genomic insights into the uncultured genus ‘Candidatus Magnetobacterium’ in the phylum Nitrospirae Wei Lin1,2,7, Aihua Deng3,7, Zhang Wang4, Ying Li2,5, Tingyi Wen3, Long-Fei Wu2,6, Martin Wu4 and Yongxin Pan1,2 1Biogeomagnetism Group, Paleomagnetism and Geochronology Laboratory, Key Laboratory of the Earth’s Deep Interior, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China; 2France-China Bio-Mineralization and Nano-Structures Laboratory, Chinese Academy of Sciences, Beijing, China; 3CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; 4Department of Biology, University of Virginia, Charlottesville, VA, USA; 5State Key Laboratory of Agro-Biotechnology and Laboratoire International Associe Franco-Chinois de Bio-Mineralisation et Nano-Structures, College of Biological Sciences, China Agricultural University, Beijing, China and 6Laboratoire de Chimie Bacte´rienne, Aix-Marseille Universite´, CNRS, Marseille Cedex 20, France Magnetotactic bacteria (MTB) of the genus ‘Candidatus Magnetobacterium’ in phylum Nitrospirae are of great interest because of the formation of hundreds of bullet-shaped magnetite magneto- somes in multiple bundles of chains per cell. These bacteria are worldwide distributed in aquatic environments and have important roles in the biogeochemical cycles of iron and sulfur. However, except for a few short genomic fragments, no genome data are available for this ecologically important genus, and little is known about their metabolic capacity owing to the lack of pure cultures. Here we report the first draft genome sequence of 3.42 Mb from an uncultivated strain tentatively named ‘Ca.
    [Show full text]
  • Emerging Players in the Regulation of Protein S-Nitrosation in Plants
    plants Review Thioredoxins: Emerging Players in the Regulation of Protein S-Nitrosation in Plants Tereza Jedelská , Lenka Luhová and Marek Petˇrivalský * Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitel ˚u27, 78371 Olomouc, Czech Republic; [email protected] (T.J.); [email protected] (L.L.) * Correspondence: [email protected] Received: 17 August 2020; Accepted: 22 October 2020; Published: 24 October 2020 Abstract: S-nitrosation has been recognized as an important mechanism of ubiquitous posttranslational modification of proteins on the basis of the attachment of the nitroso group to cysteine thiols. Reversible S-nitrosation, similarly to other redox-based modifications of protein thiols, has a profound effect on protein structure and activity and is considered as a convergence of signaling pathways of reactive nitrogen and oxygen species. This review summarizes the current knowledge on the emerging role of the thioredoxin-thioredoxin reductase (TRXR-TRX) system in protein denitrosation. Important advances have been recently achieved on plant thioredoxins (TRXs) and their properties, regulation, and functions in the control of protein S-nitrosation in plant root development, translation of photosynthetic light harvesting proteins, and immune responses. Future studies of plants with down- and upregulated TRXs together with the application of genomics and proteomics approaches will contribute to obtain new insights into plant S-nitrosothiol metabolism and its regulation. Keywords: denitrosation;
    [Show full text]
  • DHFR Inhibitors: Reading the Past for Discovering Novel Anticancer Agents
    molecules Review DHFR Inhibitors: Reading the Past for Discovering Novel Anticancer Agents Maria Valeria Raimondi 1,*,† , Ornella Randazzo 1,†, Mery La Franca 1 , Giampaolo Barone 1 , Elisa Vignoni 2, Daniela Rossi 2 and Simona Collina 2,* 1 Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, via Archirafi 32, 90123 Palermo, Italy; [email protected] (O.R.); [email protected] (M.L.F.); [email protected] (G.B.) 2 Drug Sciences Department, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, via Taramelli 12, 27100 Pavia, Italy; [email protected] (E.V.); [email protected] (D.R.) * Correspondence: [email protected] (M.V.R.); [email protected] (S.C.); Tel.: +390-912-389-1915 (M.V.R.); +390-382-987-379 (S.C.) † These Authors contributed equally to this work. Academic Editors: Simona Collina and Mariarosaria Miloso Received: 25 February 2019; Accepted: 20 March 2019; Published: 22 March 2019 Abstract: Dihydrofolate reductase inhibitors are an important class of drugs, as evidenced by their use as antibacterial, antimalarial, antifungal, and anticancer agents. Progress in understanding the biochemical basis of mechanisms responsible for enzyme selectivity and antiproliferative effects has renewed the interest in antifolates for cancer chemotherapy and prompted the medicinal chemistry community to develop novel and selective human DHFR inhibitors, thus leading to a new generation of DHFR inhibitors. This work summarizes the mechanism of action, chemical, and anticancer profile of the DHFR inhibitors discovered in the last six years. New strategies in DHFR drug discovery are also provided, in order to thoroughly delineate the current landscape for medicinal chemists interested in furthering this study in the anticancer field.
    [Show full text]
  • Free Radical Reduction by Thioredoxin Reductase at the Surface of Normal and Vitiliginous Human Keratinocytes*
    Free Radical Reduction by Thioredoxin Reductase at the Surface of Normal and Vitiliginous Human Keratinocytes* Karin U. Schallreuter, M .D ., Mark R. Pittelkow, M.D., and John M. Wood, Ph.D. Departm ents of Dermatology (KUS) an d Biochemistry (JMW) , University of Minneso ta School of Medicine, Minnea polis, and · Department of Dermatology, Mayo Clinic (MRP), Roches ter, Minnesota, U.S.A. Cell cultures of human keratinocytes contain m embrane­ ulated by calcium concentrations of the cell culture m edium. associated thioredoxin reductase that is extremely active in Stratified keratinocytes are half as active in medium con­ reducin g radicals on the outer plasma membrane. This en­ taining 2 mM Ca + + compared with 0.1 mM Ca + + con­ zyme activity was confirmed by its purification from cul­ centration. (4) Product inhibition of the enzyme occurs tures of stratified human keratinocytes by affinity column with oxidized coenzyme NADP + (i. e., 87% inhibition of chro m atography. The enzym e was assayed both in vivo enzyme activity over 30 min). The enzyme is heat stable and in vitro usin g a spin-labeled quaternary ammonium at temperatures of70°C for 10 min. It is inactivated at 75°C . compound as the substrate, under saturating conditions in A comparative study of thioredoxin reductase activity on free radical substrate. Specific activities were determined stratified differentiated and undifferentiated rapidly grow­ by monitoring the sequential decrease in the amplitude of ing celI s was performed . Also, enzyme activity was quan­ the electron spin resonance signal per unit of cell protein . titated for cultured keratinocytes isolated from vitiliginous The following properties were found: (1) Cultures of adult and normal skin of the same donor.
    [Show full text]
  • Microbiology Letters
    RESEARCH LETTER A thioredoxin reductase-like protein from the thermophile, Thermus scotoductus SA-01, displaying iron reductase activity Phillip Armand Bester, Derek Litthauer, Lizelle A. Piater & Esta van Heerden Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa Downloaded from https://academic.oup.com/femsle/article/302/2/182/647366 by guest on 29 September 2021 Correspondence: Esta van Heerden, Abstract Department of Microbial, Biochemical and Food Biotechnology, University of the Free The transition metal iron is an important element for the sustenance of life – it can State, Bloemfontein 9300, South Africa. function either as an electron acceptor or as a donor and serves as a cofactor in Tel.: 12751 401 2472; fax: 12751 444 3219; many enzymes activities. The cytoplasmic NAD(P)H-dependent ferric reductase e-mail: [email protected] in Thermus scotoductus SA-01 shares high sequence and structural similarity to prokaryotic thioredoxin reductases. Here we report the sequence of the ferric Received 9 June 2009; accepted 3 November reductase (which is typically annotated as a thioredoxin reductase-like protein) 2009. and a comparative kinetic study with the thioredoxin reductase from SA-01. Final version published online December 2009. Structurally, the most noteworthy difference, immediately apparent from the protein sequence, is the absence of the disulphide redox centre in the ferric DOI:10.1111/j.1574-6968.2009.01852.x reductase. This is the first report relating the attributes of such a redox protein to Editor: Christiane Dahl its ability to reduce a ferric substrate. Keywords ferric reductase; thioredoxin reductase; thermophilic; Thermus scotoductus SA-01.
    [Show full text]
  • Ferroptosis-Related Flavoproteins: Their Function and Stability
    International Journal of Molecular Sciences Review Ferroptosis-Related Flavoproteins: Their Function and Stability R. Martin Vabulas Charité-Universitätsmedizin, Institute of Biochemistry, Charitéplatz 1, 10117 Berlin, Germany; [email protected]; Tel.: +49-30-4505-28176 Abstract: Ferroptosis has been described recently as an iron-dependent cell death driven by peroxida- tion of membrane lipids. It is involved in the pathogenesis of a number of diverse diseases. From the other side, the induction of ferroptosis can be used to kill tumor cells as a novel therapeutic approach. Because of the broad clinical relevance, a comprehensive understanding of the ferroptosis-controlling protein network is necessary. Noteworthy, several proteins from this network are flavoenzymes. This review is an attempt to present the ferroptosis-related flavoproteins in light of their involvement in anti-ferroptotic and pro-ferroptotic roles. When available, the data on the structural stability of mutants and cofactor-free apoenzymes are discussed. The stability of the flavoproteins could be an important component of the cellular death processes. Keywords: flavoproteins; riboflavin; ferroptosis; lipid peroxidation; protein quality control 1. Introduction Human flavoproteome encompasses slightly more than one hundred enzymes that par- ticipate in a number of key metabolic pathways. The chemical versatility of flavoproteins relies on the associated cofactors, flavin mononucleotide (FMN) and flavin adenine dinu- cleotide (FAD). In humans, flavin cofactors are biosynthesized from a precursor riboflavin that has to be supplied with food. To underline its nutritional essentiality, riboflavin is called vitamin B2. In compliance with manifold cellular demands, flavoproteins have been accommo- Citation: Vabulas, R.M. dated to operate at different subcellular locations [1].
    [Show full text]
  • Mechanism and Structure of Thioredoxin Reductase from <I>Escherichia Coli</I>
    SERIAL REVIEW FLAVOPROTEIN STRUCTURE AND MECHANISM 6 Mechanism and structure of thioredoxin reductase from Escherichia coli CHARLES H. WILLIAMS, JR.’ Department of Veterans Affairs Medical Center, Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48105, USA The family of flavoproteins with redox-active cys- through a ternary complex; the kinetic evidence for tein/cystine residues that link the pyridine nucleotides such a complex is discussed.-Williams, C. H., Jr. with sulfur-containing substrates is an ever-growing one. Mechanism and structure of thioredoxin reductase In the case of thioredoxin reductase, the second sub- from Escherichia coli. FASEB J. 9, 1267-12 76 strate is the small protein thioredoxin, itself containing (1995) a redox-active disuffide, which in its reduced form is the substrate for ribonucleotide reductase. Like other mem- Key Words: thioredoxin reductase flavoprotein . disulfide reduc- bers of this family, thioredoxin reductase catalysis in- tase pyridine nucleotide thiol-disulfide interchange volves the reduction of the enzyme-bound FAD by NADPH, followed by electron transfer from the reduced THIOREDOXIN REDUCTASE CATALYZES THE REDUCTION of the flavin to the redox-active disulfide, which in turn is 12,000 Mr redox protein thioredoxin by NADPH, as shown responsible for the reduction of thioredoxin. The crystal below, where Tr(S2) is thioredoxin and Tr(SH)2 is reduced structure of the enzyme raises interesting mechanistic thioredoxin.2 questions about how this internal transfer of reducing equivalents takes place. The possible answers to these NADPH + H +Tr(S2) NADP +Tr(SH)2 questions provide the principal theme of this article. Thioredoxin reductase is a member of the pyridine nu- cleotide-disulfide oxidoreductase family of flavoenzymes.
    [Show full text]
  • Molecular Pharmacology and Antitumor Activity of Palmarumycin-Based Inhibitors of Thioredoxin Reductase
    630 Molecular pharmacology and antitumor activity of palmarumycin-based inhibitors of thioredoxin reductase Garth Powis,1 Peter Wipf,2 Stephen M. Lynch,2 Introduction 3 4 Anne Birmingham, and D. Lynn Kirkpatrick The cytosolic thioredoxin redox system is composed of thioredoxin-1 and thioredoxin reductase-1 reductase, 1Department of Experimental Therapeutics, M.D. Anderson Cancer Center, Houston, Texas; 2Department of Chemistry, which catalyzes the NADPH-dependent reduction of University of Pittsburgh, Pittsburgh, Pennsylvania; 3Arizona thioredoxin-1. Thioredoxin reductase-1 is an important Cancer Center; and 4ProlX Pharmaceuticals, Tucson, Arizona regulator of cancer cell growth and survival (1, 2). Thioredoxin-1 acting with peroxiredoxin-1 is an antioxi- dant that scavenges H2O2 (3). Thioredoxins are also able to Abstract reduce buried oxidized thiol residues in proteins (4) and The cytosolic thioredoxin redox system composed of regulate the activity of redox-sensitive transcription factors, thioredoxin-1 and the NADPH-dependent thioredoxin including p53 (5), nuclear factor-nB (6), the glucocorticoid reductase-1 reductase is an important regulator of cell receptor (7), activator protein-1 (8), hypoxia-inducible growth and survival. Thioredoxin-1 is overexpressed in factor-1 (HIF-1; ref. 9), Sp1 (10), and Nrf2 (11). Thiore- many human tumors where it is associated with doxin-1 also binds and inhibits the activity of the apoptosis- increased cell proliferation, decreased apoptosis, and inducing proteins, apoptosis signal-regulating kinase-1 (12) decreased patient survival. We hypothesized that thio- and, the tumor suppressor phosphatase and tensin homo- redoxin reductase-1 provides a target to inhibit the logue deleted on chromosome 10 (13), thus inhibiting activity of overexpressed thioredoxin-1 for the develop- apoptosis.
    [Show full text]
  • Thioredoxin Reductase Assay Kit (CS0170)
    Thioredoxin Reductase Assay Kit For the determination of thioredoxin reductase in mammalian cells and tissues Catalog Number CS0170 Storage Temperature –20 C TECHNICAL BULLETIN Product Description Thioredoxin Reductase 10 g Thioredoxin reductase is an ubiquitous enzyme that is (Catalog Number T9074) protein thought to be involved in many cellular processes such rat liver thioredoxin reductase in 50 mM as cell growth, p53 activity, and protection against Tris-HCl, pH 7.4, containing 1 mM EDTA, oxidation stress.1 The mammalian thioredoxin 300 mM NaCl, and 10% glycerol reductase reduces thioredoxins as well as non-disulfide substrates such as selenite, lipoic acids, lipid Thioredoxin Reductase Inhibitor Solution 0.05 ml hydroperoxides, and hydrogen peroxide.2 (Catalog Number T9199) The Thioredoxin Reductase Assay Kit uses a 5,5-Dithiobis(2-nitrobenzoic) acid 150 mg colorimetric assay for the determination of thioredoxin (DTNB, Catalog Number D8130) reductase activity. It is based on the reduction of 5,5-dithiobis(2-nitrobenzoic) acid (DTNB) with NADPH NADPH 25 mg to 5-thio-2-nitrobenzoic acid (TNB), which produces a (Catalog Number N6505) strong yellow color that is measured at 412 nm.3 Dimethyl Sulfoxide 7.5 ml The kit contains all the reagents needed for an easy (DMSO, Catalog Number D8418) and simple colorimetric assay of mammalian thioredoxin reductase. The kit also includes an inhibitor Reagents and Equipment Required but Not solution for specific inhibition of mammalian thioredoxin Provided reductase. Since several enzymes present in biological • Ultrapure (17 Mcm) water samples can reduce DTNB, the specific inhibitor is used • Spectrophotometer and 1 ml cuvette to determine the reduction of DTNB due only to • Microcentrifuge tubes thioredoxin reductase activity.
    [Show full text]
  • Three-Dimensional Structure of a Mammalian Thioredoxin Reductase: Implications for Mechanism and Evolution of a Selenocysteine-Dependent Enzyme
    Three-dimensional structure of a mammalian thioredoxin reductase: Implications for mechanism and evolution of a selenocysteine-dependent enzyme Tatyana Sandalova*, Liangwei Zhong†, Ylva Lindqvist*, Arne Holmgren†, and Gunter Schneider*‡ *Division of Molecular Structural Biology and †Medical Nobel Institute for Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden Edited by David R. Davies, National Institutes of Health, Bethesda, MD, and approved June 15, 2001 (received for review April 5, 2001) Thioredoxin reductases (TrxRs) from mammalian cells contain an are inhibited by a number of clinically used drugs (review in essential selenocysteine residue in the conserved C-terminal se- ref. 12). quence Gly-Cys-SeCys-Gly forming a selenenylsulfide in the oxi- Cloning and sequencing of a putative human (13) and the dized enzyme. Reduction by NADPH generates a selenolthiol, bovine and rat cytosolic TrxR (14) revealed that they are similar which is the active site in reduction of Trx. The three-dimensional to GR and not to the Escherichia coli TrxR enzyme. Compared structure of the SeCys498Cys mutant of rat TrxR in complex with with GR, the polypeptide chain of rat TrxR contains a C- -NADP؉ has been determined to 3.0-Å resolution by x-ray crystal- terminal extension of 16 residues carrying a penultimate seleno lography. The overall structure is similar to that of glutathione cysteine residue in the conserved sequence motif Gly-Cys- reductase (GR), including conserved amino acid residues binding SeCys-Gly (14, 15). The selenocysteine residue is essential the cofactors FAD and NADPH. Surprisingly, all residues directly because its replacement with cysteine results in a mutant rat interacting with the substrate glutathione disulfide in GR are TrxR enzyme with about 1% activity with Trx as substrate and conserved despite the failure of glutathione disulfide to act as a with a major loss in kcat (11).
    [Show full text]