DOCSLIB.ORG

Ferritin: Mechanistic Studies and Electron Transfer Properties

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ferritin: Mechanistic Studies and Electron Transfer Properties Brigham Young University BYU ScholarsArchive Theses and Dissertations 2006-08-08 Ferritin: Mechanistic Studies and Electron Transfer Properties Bo Zhang Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Biochemistry Commons, and the Chemistry Commons BYU ScholarsArchive Citation Zhang, Bo, "Ferritin: Mechanistic Studies and Electron Transfer Properties" (2006). Theses and Dissertations. 766. https://scholarsarchive.byu.edu/etd/766 This Dissertation is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. FERRITIN: MECHANISTIC STUDIES AND ELECTRON TRANSFER PROPERTIES by Bo Zhang A dissertation submitted to the faculty of Brigham Young University In partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Chemistry and Biochemistry Brigham Young University August 2006 BRIGHAM YOUNG UNIVERSITY GRADUATE COMMITTEE APPROVAL of a dissertation submitted by Bo Zhang This dissertation has been read by each member of the following graduate committee and by majority vote has been found to be satisfactory. ________________________________ ________________________________ Date Gerald D. Watt, Chair ________________________________ ________________________________ Date Roger G. Harrison ________________________________ ________________________________ Date Barry M. Willardson ________________________________ ________________________________ Date Craig D. Thulin ________________________________ ________________________________ Date S. Scott Zimmerman ii BRIGHAM YOUNG UNIVERSITY As chair of the candidate’s graduate committee, I have read the dissertation of Bo Zhang in its final form and have found that (1) its format, citations, and bibliographical style are consistent and acceptable and fulfill university and department style requirements; (2) its illustrative materials including figures, tables, and charts are in place; and (3) the final manuscript is satisfactory to the graduate committee and is ready for submission to the university library. ________________________________ ________________________________ Date Gerald D. Watt Chair, Graduate Committee Accepted for the Department ________________________________ Paul B. Farnsworth Department Chair Accepted for the College ________________________________ G. Rex Bryce Associate Dean, College of Physical and Mathematical Sciences iii ABSTRACT FERRITIN: MECHANISTIC STUDIES AND ELECTRON TRANSFER PROPERTIES Bo Zhang Department of Chemistry and Biochemistry Doctor of Philosophy Ferritins are ubiquitous iron storage proteins in living systems. Although much is known about the iron deposition process in ferritin and a mechanism has been developed, several important issues still remain unknown. One lingering question is the less than stoichiometric quantities of hydrogen peroxide detected in previous studies on animal ferritins. Extensive experimental data on identifying the species in competition for peroxide equivalents point to a surprising conclusion that H2O2 generated in the ferroxidase reaction is consumed by amine buffers that are commonly employed in in vitro ferritin studies, while non-nitrogen containing buffers, such as acetate, phosphate, and carbonate, do not react with H2O2. The effects of amine buffer oxidation on the 2+ Fe /O2 stoichiometry, the kinetics and the molecular mechanism of iron deposition are discussed. iv The ~2 nm ferritin shell surrounding the ~4000 Fe(O)OH mineral core was originally thought to isolate the core from the environment. However, synthesized Co- and Mn(O)OH cores in horse spleen and bacteria ferritins are shown to be rapidly reduced by ascorbic acid and horse spleen ferritin containing a reduced Fe(II) core (Fe(II)-HoSF) presumably without direct contact. Further experiments demonstrate that both Fe(II)-HoSF and Co-/Mn-ferritins bind to gold electrodes and exchange electrons through the metallic conductor. These results provide the first direct evidence for electron transfer (ET) through the ferritin shell. The nature of the ET pathway is further investigated by loading iron into native and recombinant ferritins using large oxidants that are too big to enter the ferritin interior and must accept electrons from Fe2+ through this pathway. Experimental results suggest that the endogenous redox center in heteropolymeric animal ferritins and the heme groups in bacteria ferritins mediate ET through the protein shell. Finally, the diffusion properties of ferritin pores are examined toward iron (2+ and 3+) and anion transfer. Iron transfer is studied by the formation of Prussian blue II III - ([Fe Fe (CN)6] ) encapsulated in the ferritin cavity, and is consistent with a binding- dissociation model proposed previously for iron transfer through the three-fold channels. When native HoSF is reduced by methyl viologen in saline solutions, small anions such as F-, Cl-, and Br-, accumulate in the ferritin interior while phosphate is released. No anion transfer is observed during the reduction of reconstituted HoSF with no phosphate in the core. The possibility of ferritin as an anion pump in vivo is proposed. v ACKNOWLEDGMENTS I am deeply grateful for Dr. Gerald D. Watt for his mentorship during my graduate studies. Through his example and teaching he has not only helped me become an insightful scientist but also a more open-minded human being. I hope to use what I have learned from him to benefit others in my future career. I appreciate the valuable assistance from my graduate committee. Their insightful questions and suggestions have assisted my approach and analysis of my research. Thanks in particular to Dr. John N. Harb of Department of Chemical Engineering and Dr. Richard K. Watt at BYU. I am also indebted to several graduate and undergraduate students I have worked with: Dr. Phillip Wilson, Dr. Tim Miller, Dr. Tom Lowry, Ammon Poesy, Jason Knealey, and Jared Bunker, Garrett Davis, and Kyrsten Crawford. I would like to thank sources of funding during my stay including NASA and Department of Chemistry & Biochemistry at BYU. The department has provided me the opportunity to be a graduate student and supported me with tuition, teaching assistantships, and fellowships. Finally, to my family and most importantly, to my wife, Li Li, I express my deepest appreciation for their support and patience during my graduate studies. I could never have completed this work without them. vi TABLE OF CONTENTS LIST OF TABLES………………………………………………………………………………..xi LIST OF FIGURES……………………………………………………………………………...xiii LIST OF SCHEMES……………………………………………………………………………xvii ABBREVIATIONS…………………………………………………………………………… xviii CHAPTER 1: Introduction to Ferritin…………………………………………………1 CHAPTER 2: Ferritin-Catalyzed Consumption of H2O2 by Amine Buffers Causes 2+ Variable Fe to O2 Stoichiometry of Iron Deposition in Horse Spleen Ferritin…...17 Abstract……………………...…………………………………………………...19 Introduction………………………………………………………………………20 Materials and Methods…………………………………………………………...23 Results……………………………………………………………………………26 Discussion…………...…………………………………………………………...43 CHAPTER 3: Synthesis and Characterization of Co- & Mn-Oxyhydroxide Cores Formed in Horse Spleen Ferritin………………………………………………………51 Abstract……………………...…………………………………………………...53 Introduction………………………………………………………………………54 Materials and Methods…………………………………………………………...56 Results……………………………………………………………………………61 Discussion…………...…………………………………………………………...73 vii CHAPTER 4: Electron Exchange between Fe(II)-HoSF and Co(III)/Mn(III) Reconstituted Horse Spleen and Azotobacter vinelandii Ferritins…………………...77 Abstract……………………...…………………………………………………...79 Introduction………………………………………………………………………80 Materials and Methods…………………………………………………………...83 Results……………………………………………………………………………87 Discussion…………...…………………………………………………………...97 CHAPTER 5: Anaerobic Iron Deposition into Horse Spleen, Recombinant Human Heavy and Bacteria Ferritins by Large Oxidants…………………………………...105 Abstract……………………...………………………………………………….107 Introduction……………………………………………………………………..108 Materials and Methods………………………………………………………….112 Results…………………………………………………………………………..115 Discussion…………...………………………………………………………….131 CHAPTER 6: Rate of Iron Transfer through the HoSF Shell Determined by Formation of Prussian Blue and Fe-Desferal within the Ferritin Cavity………….137 Abstract……………………...………………………………………………….139 Introduction……………………………………………………………………..140 Materials and Methods………………………………………………………….144 Results…………………………………………………………………………..149 Discussion…………...………………………………………………………….161 viii CHAPTER 7: Anions Transfer in Ferritin during Reduction of the Mineral Cores by Methyl Viologen …………………………………………………………………...169 Abstract……………………...………………………………………………….171 Introduction……………………………………………………………………..172 Materials and Methods………………………………………………………….174 Results…………………………………………………………………………..178 Discussion…………...………………………………………………………….186 REFERENCES………………………………………………………………………...191 ix x LIST OF TABLES 2+ 2+ Table 2-1. Fe /O2 stoichiometry vs buffers type and concentrations at 22 Fe /HoSF ………………………………….………………………………….…………………27 Table 4-1. First-order rate constants of electron transfer from Fe(II)-HoSF to Co- HoSF/AvBF in the absence and presence of a surface………………………………96 Table 5-1. Amount of iron in ferritin interior after Fe2+ deposition using large oxidants ………………………………….………………………………….………………..118 Table 5-2.
Load more

Recommended publications
  • Structure-Function Relationship of Metalloproteins
    RESEARCH ACTIVITIES Structure-Function Relationship of Metalloproteins Department of Life and Coordination-Complex Molecular Science Division of Biomolecular Functions FUJII, Hiroshi Associate Professor KURAHASHI, Takuya Assistant Professor CONG, Zhiqi IMS Fellow OHTSUKI, Akimichi Post-Doctoral Fellow WANG, Chunlan Graduate Student TANIZAWA, Misako Secretary Metalloproteins are a class of biologically important A d4 high-spin manganese(III) ion forms a Robin-Day Class II macromolecules, which have various functions such as oxygen mixed-valence system, in which electron transfer is occurring transport, electron transfer, oxidation, and oxygenation. These between the localized phenoxyl radical and the phenolate. This diverse functions of metalloproteins have been thought to is in clear contrast to a d8 low-spin nickel(II) ion with the depend on the ligands from amino acid, coordination struc- same salen ligand, which induces a delocalized radical (Robin- tures, and protein structures in immediate vicinity of metal Day Class III) over the two phenolate rings, as previously ions. In this project, we are studying the relationship between reported by others. The present findings point to a fascinating the electronic structures of the metal active sites and reactivity possibility that electron transfer could be drastically modu- of metalloproteins. lated by exchanging the metal ion that bridges the two redox centers. 1. One-Electron Oxidation of One-electron Oxidation Electronically-Diverse Manganese(III) and N N N N Nickel(II) Salen Complexes: Transition from M M R O O R R O O R Localized to Delocalized Mixed-Valence tBu tBu 3+ 2+ tBu tBu Ligand Radicals1) M = Mn , Ni t R = Bu, OCH3, Ph Electron Transfer Ligand radicals from salen complexes are unique mixed- Figure 1.
    [Show full text]
  • The Ferritin Fe2 Site at the Diiron Catalytic Center Controls the Reaction with O2 in the Rapid Mineralization Pathway
    The ferritin Fe2 site at the diiron catalytic center controls the reaction with O2 in the rapid mineralization pathway Takehiko Toshaa, Mohammad R. Hasana,1, and Elizabeth C. Theila,b,2 aCouncil on BioIron at Children’s Hospital Oakland Research Institute, 5700 Martin Luther King, Jr., Way, Oakland, CA 94609; and bDepartment of Nutritional Sciences and Toxicology, University of California, Berkeley, CA 94720 Edited by Edward I. Solomon, Stanford University, Stanford, CA, and approved October 13, 2008 (received for review June 2, 2008) Oxidoreduction in ferritin protein nanocages occurs at sites that Oxidoreductase/ferroxidase (Fox) catalytic centers with difer- bind two Fe(II) substrate ions and O2, releasing Fe(III)2–O products, rous binding sites, Fe1 and Fe2, occur in each ferritin subunit the biomineral precursors. Diferric peroxo intermediates form in except in animals, where a second gene encodes a catalytically ferritins and in the related diiron cofactor oxygenases. Cofactor inactive subunit (ferritin L) that co-assembles with the active iron is retained at diiron sites throughout catalysis, contrasting subunits in various ratios that depend on the tissue. The ferritin with ferritin. Four of the 6 active site residues are the same in oxidoreductase sites share properties with diiron cofactor cata- ferritins and diiron oxygenases; ferritin-specific Gln137 and variable lysts that include the first detectable reaction intermediate in Asp/Ser/Ala140 substitute for Glu and His, respectively, in diiron ferritin, a diferric peroxo (DFP) complex, characterized by cofactor active sites. To understand the selective functions of UV/visible (UV/vis), resonance Raman, Mo¨ssbauer, and ex- diiron substrate and diiron cofactor active site residues, we com- tended X-ray absorption fine structure (EXAFS) spectroscopies pared oxidoreductase activity in ferritin with diiron cofactor resi- (8–14).
    [Show full text]
  • Concepts and Tools for Mechanism and Selectivity Analysis in Synthetic Organic Electrochemistry
    Concepts and tools for mechanism and selectivity analysis in synthetic organic electrochemistry Cyrille Costentina,1,2 and Jean-Michel Savéanta,1 aUniversité Paris Diderot, Sorbonne Paris Cité, Laboratoire d’Electrochimie Moléculaire, Unité Mixte de Recherche Université–CNRS 7591, 75205 Paris Cedex 13, France Contributed by Jean-Michel Savéant, April 2, 2019 (sent for review March 19, 2019; reviewed by Robert Francke and R. Daniel Little) As an accompaniment to the current renaissance of synthetic organic sufficient to record a current-potential response but small electrochemistry, the heterogeneous and space-dependent nature of enough to leave the substrates and cosubstrates (of the order of electrochemical reactions is analyzed in detail. The reactions that follow one part per million) almost untouched. Competition of the the initial electron transfer step and yield the products are intimately electrochemical/chemical events with diffusional transport under coupled with reactant transport. Depiction of the ensuing reactions precisely mastered conditions allows analysis of the kinetics profiles is the key to the mechanism and selectivity parameters. within extended time windows (from minutes to submicroseconds). Analysis is eased by the steady state resulting from coupling of However, for irreversible processes, these approaches are blind on diffusion with convection forced by solution stirring or circulation. reaction bifurcations occurring beyond the kinetically determining Homogeneous molecular catalysis of organic electrochemical reactions step, which are precisely those governing the selectivity of the re- of the redox or chemical type may be treated in the same manner. The same benchmarking procedures recently developed for the activation action. This is not the case of preparative-scale electrolysis accom- of small molecules in the context of modern energy challenges lead to panied by identification and quantitation of products.
    [Show full text]
  • Arxiv:1706.09241V1 [Cond-Mat.Mtrl-Sci] 28 Jun 2017 Based Electrolyte Supercapacitors Remain Somewhat Sim- Confinement Might Have a Drastic Influence on the Sol- Ilar
    Confinement Effects on an Electron Transfer Reaction in Nanoporous Carbon Electrodes Zhujie Li1;2;3, Guillaume Jeanmairet2;3, Trinidad M´endez-Morales1;2;3, Mario Burbano1;3, Matthieu Haefele1, Mathieu Salanne1;2;3 1Maison de la Simulation, CEA, CNRS, Univ. Paris-Sud, UVSQ, Universit´eParis-Saclay, F-91191 Gif-sur-Yvette, France 2Sorbonne Universit´es,UPMC Univ Paris 06, CNRS, Laboratoire PHENIX, F-75005 Paris, France and 3R´eseau sur le Stockage Electrochimique´ de l'Energie´ (RS2E), FR CNRS 3459, France∗ Nanoconfinement generally leads to drastic effect on the physical and chemical properties of ionic liquids. Here we investigate how the electrochemical reactivity in such media may be impacted inside nanoporous carbon electrodes. To this end, we study a simple electron transfer reaction using molecular dynamics simulations. The electrodes are held at constant electric potential by allowing the atomic charges on the carbon atoms to fluctuate. We show that the Fe3+=Fe2+ couple dissolved in an ionic liquid exhibits a deviation with respect to Marcus theory. This behavior is rationalized by the stabilization of a solvation state of the Fe3+ cation in the disordered nanoporous electrode that is not observed in the bulk. The simulation results are fitted with a recently proposed two solvation state model, which allows us to estimate the effect of such a deviation on the kinetics of electron transfer inside nanoporous electrodes. Nanoconfinement effects strongly impact on many liq- a supercapacitor16. Among the various questions raised uid properties, such as transport, diffusion coefficients, by this study, the most important ones are: How is the phase transitions, and solvation structures1{4.
    [Show full text]
  • The Construction and Characterization of Mitochondrial Ferritin Overexpressing Mice
    Article The Construction and Characterization of Mitochondrial Ferritin Overexpressing Mice Xin Li 1,†, Peina Wang 1,†, Qiong Wu 1, Lide Xie 2, Yanmei Cui 1, Haiyan Li 1, Peng Yu 1 and Yan-Zhong Chang 1,* 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China; [email protected] (X.L.); [email protected] (P.W.); [email protected] (Q.W.); [email protected] (Y.C.); [email protected] (H.L.); [email protected] (P.Y.) 2 Department of Biomedical Engineering, Chengde Medical University, Chengde 067000, China; [email protected] * Correspondence: [email protected]; Tel.: +86-311-8078-6311 † These authors contributed equally to this work. Received: 31 May 2017; Accepted: 10 July 2017; Published: 13 July 2017 Abstract: Mitochondrial ferritin (FtMt) is a H-ferritin-like protein which localizes to mitochondria. Previous studies have shown that this protein can protect mitochondria from iron-induced oxidative damage, while FtMt overexpression in cultured cells decreases cytosolic iron availability and protects against oxidative damage. To investigate the in vivo role of FtMt, we established FtMt overexpressing mice by pro-nucleus microinjection and examined the characteristics of the animals. We first confirmed that the protein levels of FtMt in the transgenic mice were increased compared to wild-type mice. Interestingly, we found no significant differences in the body weights or organ to body weight ratios between wild type and transgenic mice. To determine the effects of FtMt overexpression on baseline murine iron metabolism and hematological indices, we measured serum, heart, liver, spleen, kidney, testis, and brain iron concentrations, liver hepcidin expression and red blood cell parameters.
    [Show full text]
  • The Potential for Transition Metal-Mediated Neurodegeneration in Amyotrophic Lateral Sclerosis
    REVIEW ARTICLE published: 23 July 2014 AGING NEUROSCIENCE doi: 10.3389/fnagi.2014.00173 The potential for transition metal-mediated neurodegeneration in amyotrophic lateral sclerosis David B. Lovejoy* and Gilles J. Guillemin Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia Edited by: Modulations of the potentially toxic transition metals iron (Fe) and copper (Cu) are impli- Roger S. Chung, Macquarie cated in the neurodegenerative process in a variety of human disease states including University, USA amyotrophic lateral sclerosis (ALS). However, the precise role played by these metals is Reviewed by: Junming Wang, University of still very much unclear, despite considerable clinical and experimental data suggestive of Mississippi Medical Center, USA a role for these elements in the neurodegenerative process.The discovery of mutations in Ramon Santos El-Bachá, Universidade the antioxidant enzyme Cu/Zn superoxide dismutase 1 (SOD-1) in ALS patients established Federal da Bahia, Brazil the first known cause of ALS. Recent data suggest that various mutations in SOD-1 affect *Correspondence: metal-binding of Cu and Zn, in turn promoting toxic protein aggregation. Copper home- David B. Lovejoy, Macquarie University, Australian School of ostasis is also disturbed in ALS, and may be relevant to ALS pathogenesis. Another set Advanced Medicine, Motor Neuron of interesting observations in ALS patients involves the key nutrient Fe. In ALS patients, and Neurodegenerative Diseases Fe loading can be inferred by studies showing increased expression of serum ferritin, an Research Group, Building F10A, 2 Fe-storage protein, with high serum ferritin levels correlating to poor prognosis. Magnetic Technology Place, NSW, 2109, Australia resonance imaging of ALS patients shows a characteristic T2 shortening that is attributed e-mail: [email protected] to the presence of Fe in the motor cortex.
    [Show full text]
  • Mitochondria in Hematopoiesis and Hematological Diseases
    Oncogene (2006) 25, 4757–4767 & 2006 Nature Publishing Group All rights reserved 0950-9232/06 $30.00 www.nature.com/onc REVIEW Mitochondria in hematopoiesis and hematological diseases M Fontenay1, S Cathelin2, M Amiot3, E Gyan1 and E Solary2 1Inserm U567, Institut Cochin, Department of Hematology, Paris, Cedex, France; 2Inserm U601, Biology Institute, Nantes, Cedex, France and 3Inserm U517, Faculty of Medicine, Dijon, France Mitochondria are involved in hematopoietic cell homeo- Introduction stasis through multiple ways such as oxidative phosphor- ylation, various metabolic processes and the release of As in other tissues, mitochondria play many important cytochrome c in the cytosol to trigger caspase activation roles in hematopoietic cell homeostasis, including the and cell death. In erythroid cells, the mitochondrial steps production of adenosine triphosphate (ATP) by the in heme synthesis, iron (Fe) metabolism and Fe-sulfur process of oxidative phosphorylation, the release of (Fe-S) cluster biogenesis are of particular importance. death-promoting factors upon apoptotic stimuli and a Mutations in the specific d-aminolevulinic acid synthase variety of metabolic pathways such as heme synthesis. (ALAS) 2 isoform that catalyses the first and rate-limiting Mitochondria could also play a role in specific pathways step in heme synthesis pathway in the mitochondrial of hematopoietic cell differentiation through caspase matrix, lead to ineffective erythropoiesis that charac- activation.Alterations of these mitochondrial functions terizes X-linked
    [Show full text]
  • Oxidation-Reduction Reactions
    Oxidation-Reduction Reactions What is an Oxidation-Reduction, or Redox, reaction? Oxidation-reduction reactions, or redox reactions, are technically defined as any chemical reaction in which the oxidation number of the participating atom, ion, or molecule of a chemical compound changes. Some common redox reactions include fire, rusting of metals, browning of fruit, and photosynthesis. In simpler terms, redox reactions involve the transfer of electrons from one substance to another. In a redox reaction, electrons can never be “lost”; if one substance loses electrons, another substance must gain an equal number of electrons. Therefore, oxidation and reduction always happen at the same time; they are a matched set. What is Oxidation? Oxidation is the loss of electrons by an atom, ion, or molecule. The atom, ion, or molecule that is oxidized will become more positively charged. Oxidation may also involve the addition of oxygen or the loss of hydrogen. What is Reduction? Reduction is the gain of electrons by an atom, ion, or molecule. The atom, ion, or molecule that is reduced will become more negatively charged. Reduction may also involve the loss of oxygen or the gain of hydrogen. Tips for determining if an atom, ion, or compound has been Oxidized or Reduced: • Remembering one of the two following mnemonics can be of assistance in determining the difference between oxidation and reduction: 1) OIL RIG- Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons) or 2) LEO GER- Loss of Electrons- Oxidation, Gain of Electrons- Reduction • Atoms of metals tend to lose electrons to form positive ions (oxidation) • Atoms of non-metals tend to gain electrons to form negative ions (reduction).
    [Show full text]
  • Frataxin and Mitochondrial Fes Cluster Biogenesis Timothy L
    Wayne State University DigitalCommons@WayneState Biochemistry and Molecular Biology Faculty Department of Biochemistry and Molecular Biology Publications 8-27-2010 Frataxin and Mitochondrial FeS Cluster Biogenesis Timothy L. Stemmler Wayne State University, [email protected] Emmanuel Lesuisse Institut Jacques Monod Debumar Pain University of Medicine and Dentistry, New Jersey Andrew Dancis University of Pennsylvania Recommended Citation Stemmler, T. L., Lesuisse, E., Pain, D., and Dancis, A. (2010) J. Biol. Chem. 285, 26737-26743. doi:10.1074/jbc.R110.118679 Available at: http://digitalcommons.wayne.edu/med_biochem/13 This Article is brought to you for free and open access by the Department of Biochemistry and Molecular Biology at DigitalCommons@WayneState. It has been accepted for inclusion in Biochemistry and Molecular Biology Faculty Publications by an authorized administrator of DigitalCommons@WayneState. This is the author's post-print version, previously appearing in the Journal of Biological Chemistry , 2010, 285, 35, 26737-43. Available online at: http://www.jbc.org/ Frataxin and mitochondrial Fe-S cluster biogenesis | Timothy Stemmler, et. al Frataxin and mitochondrial Fe-S cluster biogenesis Timothy L. Stemmler 1, Emmanuel Lesuisse 2, Debumar Pain 3, Andrew Dancis 4 1. Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit, Michigan 48201 2. Laboratoire Mitochondrie, Metaux et Stress Oxydant, Institut Jacques Monod, CNRS-Universite Paris Diderot, France 75205 3. Department of Pharmacology and Physiology, UMDNJ, New Jersey Medical School, Newark, New Jersey 07101 4. Department of Medicine, Division of Hematology-Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 Abstract Friedreich’s ataxia is an inherited neurodegenerative disease caused by frataxin deficiency.
    [Show full text]
  • Design and Fine-Tuning Redox Potentials of Metalloproteins Involved in Electron Transfer in Bioenergetics
    1 Design and Fine-tuning Redox Potentials of Metalloproteins Involved in Electron Transfer in Bioenergetics Parisa Hosseinzadeh and Yi Lu Abstract: 1. Introduction A significant portion of biological processes are involved with providing vital energy sources such as ATP, and controlling the flow of energy through living systems. These bioenergetics processes, the most important of which are photosynthesis and respiration, require electron transfer (ET) between different redox partners. Metalloproteins are one of the most widely used ET centers in biology. They can be classified into three major classes: cupredoxins, which include type 1 copper (T1Cu) proteins and CuA centers [1- 10], cytochromes [10-17], and iron-sulfur (FeS) proteins [10,18-24]. Each class of ET proteins transfer electrons between different redox partners which possess different reduction potentials (E°) (Figure 1). Therefore, the ET centers need to adjust their E° in a way that matches those of their redox partners. No single class of protein can cover the entire range of physiological E°, which is between ~ -1V, at which protons are reduced to H2, and 1V, at which water is oxidized to O2. Cupredoxins usually function at the high end of the E°, while FeS proteins are mostly involved in ET reactions possessing relatively low E° [10]. The E°’s of FeS proteins overlap significantly with those of cytochromes that often have intermediate E° among the three classes of ET proteins. Figure 1. Reduction potential range of metal centers in electron transfer metalloprotein. Adapted from ref. [10] 2 In this review, we first describe the importance of tuning E° of ET centers, including the metalloproteins described above.
    [Show full text]
  • Light Induced Electron Transfer of Metal Complexes
    Electron and Proton Transfer in Chemistry and Biology, edited by A. Müller et al. Studies in Physical and Theoretical Chemistry, Vol. 78 €> 1992 Elsevier Science Publishers B.V. All rights reserved. Light Induced Electron Transfer of Metal Complexes A. Vogler and H. Kunkely Institut für Anorganische Chemie Universität Regensburg Universitätsstraße 31 D-8400 Regensburg (Germany) * Summary Light induced electron transfer of metal complexes has been studied extensively during the last decade. This interest was stimulated by attempts to develop an artificial photosyn• thesis for the conversion and chemical storage of solar energy. Even if this goal has not yet been achieved photochemical redox processes of coordination compounds are now much better understood. In this review the various possibilities of photoinduced electron transfer are discussed and illustrated by selected examples. A distinction is made between intra- and intermolecular electron transfer which may occur as a direct optical transition or by an excited state electron transfer mechanism. Introduction The study of photochemical electron transfer processes involving coordination compounds (refs. 1-17) has become an important research subject during the last 10 years. These investigations were initiated, at least partially, by the desire to create an artificial photosynthetic system for the conversion and chemical storage of solar energy (refs. 18-20). It is well known that natural photosynthesis requires a light induced electron transfer as the basic process employing chlorophyll as the key compound. In order to imitate nature we have to improve our knowledge of photoredox processes. Coordination compounds, particularly those of transition metals, are excellent candi• dates for such studies. Metal complexes are generally redox active.
    [Show full text]
  • Kinetics and Mechanisms of Electron Transfer Reactions of Metal Complexes Ormond Jerry Parker Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1968 Kinetics and mechanisms of electron transfer reactions of metal complexes Ormond Jerry Parker Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Physical Chemistry Commons Recommended Citation Parker, Ormond Jerry, "Kinetics and mechanisms of electron transfer reactions of metal complexes " (1968). Retrospective Theses and Dissertations. 4619. https://lib.dr.iastate.edu/rtd/4619 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. This dissertation has been microfihned exactly as received 69-9882 PARKER, Ormond Jerry, 1939- KINETICS AND MECHANISMS OF ELECTRON TRANSFER REACTIONS OF METAL COMPLEXES. Iowa State University, Ph.D., 1968 Chemistry, physical University Microfilms. Inc., Ann Arbor, Michigan KINETICS AND MECHANISMS OF ELECTRON TRANSFER REACTIONS OF METAL COMPLEXES by Ormond Jerry Parker A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Major Subject: Physical Chemistry Approved: Signature was redacted for privacy. IffyCharge of Maj<6r Work Signature was redacted for privacy.
    [Show full text]