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  • 1
    Online-Ressource
    Online-Ressource
    Cham :Springer International Publishing AG,
    Schlagwort(e): Metalloenzymes. ; Electronic books.
    Materialart: Online-Ressource
    Seiten: 1 online resource (362 pages)
    Ausgabe: 1st ed.
    ISBN: 9783319124155
    Serie: Metal Ions in Life Sciences Series ; v.15
    DDC: 572.752
    Sprache: Englisch
    Anmerkung: Intro -- Historical Development and Perspectives of the Series -- Metal Ions in Life Sciences. -- Preface to Volume 15 -- Sustaining Life on Planet Earth: Metalloenzymes Mastering Dioxygen and Other Chewy Gases -- Contents -- Contributors to Volume 15 -- Titles of Volumes 1-44 in the Metal Ions in Biological Systems Series -- Contents of Volumes in the Metal Ions in Life Sciences Series -- Volume 1 Neurodegenerative Diseases and Metal Ions -- Volume 2 Nickel and Its Surprising Impact in Nature -- Volume 3 The Ubiquitous Roles of Cytochrome P450 Proteins -- Volume 4 Biomineralization. From Nature to Application -- Volume 5 Metallothioneins and Related Chelators -- Volume 6 Metal-Carbon Bonds in Enzymes and Cofactors -- Volume 7 Organometallics in Environment and Toxicology -- Volume 8 Metal Ions in Toxicology: Effects, Interactions, Interdependencies -- Volume 9 Structural and Catalytic Roles of Metal Ions in RNA -- Volume 10 Interplay between Metal Ions and Nucleic Acids -- Volume 11 Cadmium: From Toxicity to Essentiality -- Volume 12 Metallomics and the Cell -- Volume 13 Interrelations between Essential Metal Ions and Human Diseases -- Volume 14 The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment -- Volume 15 Sustaining Life on Planet Earth: Metalloenzymes Mastering Dioxygen and Other Chewy Gases (this book) -- Volume 16 The Alkali Metal Ions: Their Role for Life (in preparation) -- Chapter 1: The Magic of Dioxygen -- 1 Introduction -- 2 The Rise of Dioxygen in the Atmosphere -- 3 The Dark Side of Dioxygen -- 4 Outlook -- Abbreviations and Definitions -- References -- Chapter 2: Light-Dependent Production of Dioxygen in Photosynthesis -- 1 Introduction -- 2 Geometric and Electronic Structure of the Mn4CaO5 Cluster -- 2.1 Geometric and Electronic Structural Changes During S State Transitions. , 3 X-Ray Diffraction and Spectroscopy of Photosystem II at Room Temperature Using Femtosecond X-Ray Pulses -- 3.1 Simultaneous X-Ray Spectroscopy and Diffraction of Photosystem II -- 3.1.1 X-Ray Emission Spectroscopy of Photosystem II at Room Temperature Using the X-Ray Free Electron Laser -- 3.1.2 X-Ray Diffraction Studies of Photosystem II at Room Temperature Using the X-Ray Free Electron Laser -- 3.2 Intermediate S State Transitions and Mechanism of Dioxygen Evolution -- 3.2.1 X-Ray Free Electron Laser-Based X-Ray Diffraction and X-Ray Emission Spectroscopy of Photosystem II in the S1 and S2 Sta... -- 4 Membrane Inlet Mass Spectrometry and Photosystem II -- 4.1 Membrane Inlet Mass Spectrometry and S State Turnover in X-Ray Free Electron Laser Studies -- 4.2 Time-Resolved Membrane Inlet Mass Spectrometry and Insights into Oxygen Evolution -- 5 Concluding Remarks and Future Directions -- Abbreviations and Definitions -- References -- Chapter 3: Production of Dioxygen in the Dark: Dismutases of Oxyanions -- 1 Introduction -- 2 Geochemistry of the Oxochlorates -- 2.1 Oxochlorates as Respiratory Anions -- 2.2 Natural Abundance of Perchlorate on Earth -- 2.3 Atmospheric and Extraterrestrial Origins of Perchlorate -- 2.4 Perchlorate on Mars -- 3 Perchlorate Respiration -- 3.1 Diversity of Perchlorate-Respiring Microbes -- 3.2 Genetics and Genomics of Perchlorate-Respiring Microbes -- 3.3 (Per)chlorate Reductases -- 3.4 Chlorite Dismutases and Perchlorate Respiration -- 4 Oxygen Generation by Chlorite Dismutases -- 4.1 Structures -- 4.1.1 Primary Structures: Diversity and Hallmarks of O2 Generation -- 4.1.2 Heme-Binding Domain -- 4.1.3 Active Site -- 4.1.4 Tertiary Structures and Oligomerization States -- 4.2 Reactivity and Mechanism -- 4.2.1 Diversity of Reactions Catalyzed by Chlorite Dismutases -- 4.2.2 Possible Pathways for O-O Formation. , 4.2.3 Catalytic Efficiency -- 4.2.4 Reaction Intermediates -- 4.2.5 Structure-Activity Relationships: Highlights -- 4.2.6 Heme and Protein Stability in Diverse Chlorite Dismutase Family Proteins -- 5 Synthetic and Biochemical Models -- 5.1 Chlorite as Reagent with Related Synthetic Metalloporphyrins -- 5.2 Reactions of Chlorite with Horseradish Peroxidase: Implications for Chlorite Dismutases -- 6 General Conclusions -- Abbreviations and Definitions -- References -- Chapter 4: Respiratory Conservation of Energy with Dioxygen: Cytochrome c Oxidase -- 1 Introduction -- 2 The Structures of Bovine Heart Cytochrome c Oxidase -- 2.1 Purification and Crystallization of Bovine Heart Cytochrome c Oxidase -- 2.2 X-Ray Structure of the Protein Moiety -- 2.3 Structure and Stoichiometry of the Metal Sites -- 2.4 Lipid Structures and Contents -- 3 Mechanism of Dioxygen Reduction -- 3.1 Resonance Raman Analysis -- 3.2 X-Ray Structural Data -- 3.3 Biomimetic Studies -- 4 Proton Pump Mechanism -- 4.1 Coupling Between Dioxygen Reduction and Proton Pump -- 4.2 Single Electron Injection Analyses of the Intermediates of the Catalytic Cycle -- 4.2.1 FO Transition -- 4.2.2 The Other Transitions -- 4.3 D-Pathway Mechanism -- 4.3.1 Water-Gated Mechanism -- 4.3.2 Experimental Results Suggesting that Both Chemical and Pumped Protons Are Transferred Through the D-Pathway -- 4.4 H-Pathway Mechanism -- 4.4.1 Structure and Function of the H-Pathway -- 4.4.2 The Structure for Proton Collection and Timely Closure of the Water Channel -- 4.4.3 Mutational Analyses of the H-Pathway -- 4.5 Diversity in Proton Transfer Pathways -- 5 General Conclusions -- Abbreviations and Definitions -- References -- Chapter 5: Transition Metal Complexes and the Activation of Dioxygen -- 1 Introduction -- 1.1 Overview -- 1.2 Paradigm for Dioxygen Activation by Metalloprotein Active Sites. , 2 Dioxygen Activation by Iron Porphyrins -- 2.1 Dioxygen Activation at Heme-Iron Centers: Lessons from Cytochrome P450cam -- 2.2 Iron-Porphyrin Complexes as Heme Models -- 2.2.1 Fe(III)-Superoxo Intermediates -- 2.2.2 Fe(III)-Peroxo Intermediates -- 2.2.3 Fe(III)-Hydroperoxo (Alkylperoxo) Intermediates -- 2.2.4 Fe(IV)-Oxo Intermediates -- 2.2.5 Reactivity of Iron-Porphyrin Intermediates -- Factors Affecting O-O Bond Cleavage: Heterolysis versus Homolysis -- Alkane Hydroxylation by Fe(IV)-Oxo Intermediates -- O-Atom Transfer Reactivity -- Role of the Axial Ligand in Hydroxylation and O-Atom Transfer Reactions -- 2.3 Iron-Porphyrin/Copper Complexes as Cytochrome c Oxidase Models -- 2.3.1 (mu-Peroxo)Iron-Copper Intermediates -- 2.3.2 Reactivity of Iron-Copper Dioxygen Intermediates -- 3 Dioxygen Activation by Non-heme Iron Complexes -- 3.1 Monoiron Models of Mononuclear Non-heme Iron Active Sites -- 3.1.1 Monoiron Superoxo and Hydroperoxo Complexes -- 3.1.2 Monoiron(IV)-Oxo Complexes -- 3.1.3 Monoiron-Cofactor Complexes: Catecholates and α-Ketoglutarates -- 3.2 Diiron Models of Dinuclear Non-heme Diiron Active Sites -- 3.2.1 (Peroxo)diiron Complexes -- 3.2.2 High Valent Diiron-Oxo Complexes -- 4 Dioxygen Activation by Copper Complexes -- 4.1 Mononuclear Models of Monocopper Active Sites in Enzymes -- 4.1.1 1:1 Cu/O2 Adducts -- 4.1.2 CuOOR Complexes -- 4.1.3 Targeting [CuO]+ and Related Monocopper Species -- 4.2 Dicopper Models of Dicopper Active Sites in Enzymes -- 4.2.1 Peroxo- and Bis(mu-oxo)dicopper Complexes -- 4.2.2 (mu-Oxo)dicopper Complexes -- 4.3 Tricopper Models of Multicopper Active Sites in Enzymes -- 5 Concluding Remarks -- Abbreviations and Definitions -- References -- Chapter 6: Methane Monooxygenase: Functionalizing Methane at Iron and Copper -- 1 Introduction -- 2 Particulate Methane Monooxygenase -- 2.1 Architecture -- 2.2 Metal Centers. , 2.3 Identifying the Active Site -- 2.3.1 Proposed Active Sites -- 2.3.2 Evidence for a Dicopper Active Site -- 2.4 Substrate Access and Product Egress from the Dicopper Site -- 2.4.1 Access to the Substrate-Binding Pocket -- 2.4.2 Substrate and Product Channeling -- 2.4.3 Electron Sources -- 2.5 Mechanism -- 2.5.1 Spectroscopic Identification of an Oxygen Intermediate -- 2.5.2 Computational Studies and Comparisons to Copper Model Compounds -- 2.5.3 Mechanism of C-H Bond Breaking -- 2.6 Unresolved Questions -- 3 Soluble Methane Monooxygenase -- 3.1 Genetics and System Components -- 3.1.1 Soluble Methane Monooxygenase -- 3.1.2 Related Bacterial Multicomponent Monooxygenases and Substrate Specificities -- 3.2 Component Structures and Function -- 3.2.1 Soluble Methane Monooxygenase Hydroxylase -- 3.2.2 The Reductase and Electron Transfer to the Hydroxylase -- 3.2.3 The Regulatory Protein and Interactions with the Hydroxylase -- 3.3 The Diiron Center -- 3.3.1 The Oxidized Hydroxylase -- 3.3.2 The Reduced Hydroxylase -- 3.4 Protein Component Complexes -- 3.4.1 Reductase Binding and Effects on the Hydroxylase -- 3.4.2 Hydroxylase Activation by the Regulatory Protein -- 3.4.3 Structures of Regulatory Protein-Hydroxylase Complexes -- 3.4.4 The Activated Soluble Methane Monooxygenase Diiron Center -- 3.4.5 Comparisons to Toluene Monooxygenases and Phenyl Hydroxylase -- 3.5 Substrate Access to the Catalytic Diiron Center -- 3.5.1 Cavities for O2 and Hydrocarbons -- 3.5.2 Proton Delivery -- 3.6 Dimetallic Activation of O2 and Methane -- 3.6.1 Reaction of O2 with the Reduced Hydroxylase -- 3.6.2 Peroxo Intermediates -- 3.6.3 Intermediates Q and Q* -- 3.6.4 The Product-Bound Hydroxylase -- 3.6.5 C-H Bond Activation by Different Intermediates -- 4 Concluding Remarks and Future Directions -- Abbreviations and Definitions -- References. , Chapter 7: Metal Enzymes in ``Impossible´´ Microorganisms Catalyzing the Anaerobic Oxidation of Ammonium and Methane.
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  • 2
    Online-Ressource
    Online-Ressource
    Dordrecht :Springer Netherlands,
    Schlagwort(e): Gases -- Environmental aspects. ; Electronic books.
    Materialart: Online-Ressource
    Seiten: 1 online resource (363 pages)
    Ausgabe: 1st ed.
    ISBN: 9789401792691
    Serie: Metal Ions in Life Sciences Series ; v.14
    DDC: 541.0423
    Sprache: Englisch
    Anmerkung: Intro -- Historical Development and Perspectives of the Series -- Metal Ions in Life Sciences. -- Preface to Volume 14 -- The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment -- Contents -- Contributors to Volume 14 -- Titles of Volumes 1-44 in the Metal Ions in Biological Systems Series -- Contents of Volumes in the Metal Ions in Life Sciences Series -- Volume 1 Neurodegenerative Diseases and Metal Ions -- Volume 2 Nickel and Its Surprising Impact in Nature -- Volume 3 The Ubiquitous Roles of Cytochrome P450 Proteins -- Volume 4 Biomineralization. From Nature to Application -- Volume 5 Metallothioneins and Related Chelators -- Volume 6 Metal-Carbon Bonds in Enzymes and Cofactors -- Volume 7 Organometallics in Environment and Toxicology -- Volume 8 Metal Ions in Toxicology: Effects, Interactions, Interdependencies -- Volume 9 Structural and Catalytic Roles of Metal Ions in RNA -- Volume 10 Interplay between Metal Ions and Nucleic Acids -- Volume 11 Cadmium: From Toxicity to Essentiality -- Volume 12 Metallomics and the Cell -- Volume 13 Interrelations between Essential Metal Ions and Human Diseases -- Volume 14 The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment (this book) -- Volume 15 Sustaining Life on Planet Earth: Metalloenzymes Mastering Dioxygen and Other Chewy Gases (in press) -- Volume 16 The Alkali Metal Ions: Their Role for Life (in preparation) -- Chapter 1: The Early Earth Atmosphere and Early Life Catalysts -- 1 The Early Earth Atmosphere and Lithosphere -- 1.1 Earth´s Internal Structure -- 2 Catalysts in the Early Earth -- 3 Clays as Possible Catalysts in the Synthesis of Biomolecules -- 4 General Conclusions -- Abbreviations -- References -- Chapter 2: Living on Acetylene. A Primordial Energy Source -- 1 Introduction -- 2 Acetylene -- 2.1 Properties of Acetylene. , 2.2 Sources and Bioavailability of Acetylene on Earth and Other Planets -- 3 Bacteria Living on Acetylene -- 3.1 Pelobacter acetylenicus -- 4 Acetylene Hydratase from Pelobacter acetylenicus -- 4.1 Biochemical and Spectroscopic Properties -- 4.2 Molybdenum-Substituted Enzyme -- 4.3 Crystallization -- 4.4 Structural Overview -- 4.5 Active Site Setup -- 4.6 Site-Directed Mutagenesis -- 4.7 Density Functional Theory Calculations on the Substrate Binding Mode and Amino Acid Protonation States -- 4.8 Towards the Reaction Mechanism -- 5 Conclusions -- Abbreviations and Definitions -- References -- Chapter 3: Carbon Monoxide. Toxic Gas and Fuel for Anaerobes and Aerobes: Carbon Monoxide Dehydrogenases -- 1 Introduction -- 1.1 Chemistry of Carbon Monoxide -- 1.2 Carbon Monoxide in the Biosphere -- 1.2.1 Biological Cycle of Carbon Monoxide -- 1.2.1.1 Sources of Carbon Monoxide -- 1.2.1.2 Removal of Carbon Monoxide -- 1.2.2 Use of Carbon Monoxide under Aerobic and Anaerobic Conditions -- 1.2.2.1 Fates of Carbon Monoxide under Aerobic Conditions -- 1.2.2.2 Fates of Carbon Monoxide under Anaerobic Conditions -- 2 Structure and Function of Carbon Monoxide Dehydrogenases -- 2.1 Cu,Mo-Containing Carbon Monoxide Dehydrogenases -- 2.1.1 Structure of Cu,Mo-Carbon Monoxide Dehydrogenases -- 2.1.2 Spectroscopic Investigations -- 2.1.3 Enzymatic Activity -- 2.1.4 Reaction Mechanism -- 2.2 Monofunctional Ni,Fe-Containing Carbon Monoxide Dehydrogenases -- 2.2.1 Function, Distribution, and Overall Structure -- 2.2.2 Electronic States and Structure of Cluster C -- 2.2.3 Pathways and Channels Involved in Catalysis -- 2.2.4 Inhibited States of Cluster C -- 2.2.5 Mechanism of Reversible Carbon Dioxide Reduction at Cluster C -- 2.3 Bifunctional Ni,Fe-Containing Carbon Monoxide Dehydrogenases -- 2.3.1 Classification and Distribution. , 2.3.2 Structural Characterization of Bacterial CODH/ACS -- 2.3.3 Substrate Binding and Reaction Mechanism -- 2.4 Cu,Mo versus Ni,Fe: Parallels and Differences in Catalytic Strategies -- 3 Concluding Remarks and Future Directions -- Abbreviations -- References -- Chapter 4: Investigations of the Efficient Electrocatalytic Interconversions of Carbon Dioxide and Carbon Monoxide by Nickel-C... -- 1 Direct Carbon Dioxide/Carbon Monoxide Interconversions in Biology -- 2 Nickel-Containing Carbon Monoxide Dehydrogenases -- 3 Protein Film Electrochemistry -- 4 Carbon Monoxide Dehydrogenases as Electrocatalysts -- 4.1 The Electrocatalytic Voltammograms of Class IV Enzymes -- 4.2 The Electrocatalytic Voltammograms of Class III Enzymes -- 5 Potential-Dependent Reactions with Inhibitors -- 5.1 How Class IV Carbon Monoxide Dehydrogenases Respond to Cyanide -- 5.2 How Class IV Carbon Monoxide Dehydrogenases Respond to Cyanate -- 5.3 How Class IV Carbon Monoxide Dehydrogenases Respond to Sulfide and Thiocyanate -- 6 Demonstrations of Technological Significance -- 7 Conclusions -- Abbreviations -- References -- Chapter 5: Understanding and Harnessing Hydrogenases, Biological Dihydrogen Catalysts -- 1 Introduction -- 2 Dihydrogen Cycles and Hydrogenases -- 2.1 The Global Dihydrogen Cycle -- 2.2 Dihydrogen Cycling in Microbial Communities -- 2.3 Solar Dihydrogen Economy -- 2.3.1 Hydrogenase Photoelectrolysis Devices -- 2.3.2 Photosynthetic Dihydrogen -- 3 [NiFe] Hydrogenases -- 3.1 Structure and Function -- 3.1.1 Mechanisms for Dioxygen Tolerance -- 3.1.2 [NiFeSe] Hydrogenases -- 3.2 Biosynthesis -- 4 Nickel-Free Hydrogenases: [FeFe] and [Fe] Enzymes -- 4.1 [FeFe] Hydrogenase Structure and Function -- 4.2 [FeFe] Hydrogenase Biosynthesis -- 4.3 [Fe] Hydrogenases -- 5 Insights into Hydrogenase Mechanism from Small Molecule Mimics -- 6 General Conclusions. , Abbreviations and Definitions -- References -- Chapter 6: Biochemistry of Methyl-Coenzyme M Reductase: The Nickel Metalloenzyme that Catalyzes the Final Step in Synthesis an... -- 1 Introduction -- 1.1 Nickel Enzymes Involved in Metabolism of Environment- and Energy-Relevant Gases -- 1.2 Methyl-Coenzyme M Reductase and Its Involvement in Generation and Utilization of Methane -- 1.3 Ramifications of Methanogenesis in Energy and the Environment -- 1.4 Discoveries Underpinning Recent Studies of Methyl-Coenzyme M Reductase -- 2 Structure and Properties of Methyl-Coenzyme M Reductase and Its Bound Coenzyme F430 -- 2.1 Structure, Properties, and Reactivity of Coenzyme F430 -- 2.2 Structure, Properties, and Reactivity of Methyl-Coenzyme M Reductase -- 3 Redox and Coordination Properties of the Nickel Center in Methyl-Coenzyme M Reductase -- 3.1 Coordination and Oxidation States of the Free F430 Cofactor and Its Pentamethyl Ester Derivative -- 3.2 Coordination and Oxidation States of the Nickel Center -- 4 The Catalytic Mechanism of Methyl-Coenzyme M Reductase -- 5 Summary and Prospects for Future Science and Technology -- Abbreviations -- References -- Chapter 7: Cleaving the N,N Triple Bond: The Transformation of Dinitrogen to Ammonia by Nitrogenases -- 1 Introduction -- 2 The Structural and Biochemical Properties of Mo-Nitrogenase -- 2.1 The Fe Protein and Its Associated Metal Clusters -- 2.1.1 The Polypeptide -- 2.1.2 The [Fe4S4] Cluster -- 2.2 The MoFe Protein and Its Associated Metal Clusters -- 2.2.1 The Polypeptide -- 2.2.2 The P-cluster -- 2.2.3 The FeMoco -- 3 The Catalytic Mechanism of Mo-Nitrogenase -- 3.1 The Thorneley-Lowe Model -- 3.1.1 The Fe Protein Cycle -- 3.1.2 The MoFe Protein Cycle -- 3.2 Further Development and Modifications of the Thorneley-Lowe Model -- 3.2.1 Intermediates of the MoFe Protein Cycle. , 3.2.1.1 The Substrate-Free M4 Intermediate -- 3.2.1.2 The M7 and M8 Intermediates -- 3.2.2 The Reductive Dihydrogen Elimination Mechanism -- 3.2.3 The Alternating Dinitrogen Reduction Pathway -- 4 The Distinct Structural and Catalytic Features of V-Nitrogenase -- 4.1 The Structural Features -- 4.1.1 The Fe Protein -- 4.1.2 The VFe Protein -- 4.2 The Catalytic Features -- 4.2.1 The Reduction of Dinitrogen -- 4.2.2 The Reduction of Carbon Monoxide -- 5 Conclusions -- Abbreviations -- References -- Chapter 8: No Laughing Matter: The Unmaking of the Greenhouse Gas Dinitrogen Monoxide by Nitrous Oxide Reductase -- 1 Introduction: The Biogeochemical Nitrogen Cycle -- 2 Nitrous Oxide: Environmental Effects and Atmospheric Chemistry -- 2.1 Chemical Properties of Dinitrogen Monoxide -- 2.2 Nitrous Oxide, the Greenhouse Effect, and Ozone Depletion -- 2.3 Abiotic and Biotic Sources -- 2.4 Bacterial Denitrification -- 3 Nitrous Oxide Reductase -- 3.1 Anatomy of an Unusual Copper Enzyme -- 3.1.1 Distinct Forms of the Enzyme -- 3.1.2 Three-Dimensional Structures -- 3.2 CuA: More than an Electron Transfer Center -- 3.2.1 Spectroscopic Properties of CuA -- 3.2.2 Three-Dimensional Structure(s) of CuA -- 3.2.3 Unexpected Flexibility: CuA in P. stutzeri Nitrous Oxide Reductase -- 3.3 The Tetranuclear CuZ Center -- 3.3.1 Structural Data on CuZ -- 3.3.2 States of CuZ and Catalytic Properties -- 4 Biogenesis and Assembly of Nitrous Oxide Reductase -- 4.1 The nos Operon -- 4.2 Protein Maturation and CuA Insertion -- 4.3 Assembly of CuZ -- 5 Activation of Nitrous Oxide: The Workings of Nitrous Oxide Reductase -- 5.1 Substrate Access -- 5.2 Gated Electron Transfer -- 5.3 Activation of Nitrous Oxide -- 5.4 The Fate of the Products -- 6 General Conclusions -- Abbreviations and Definitions -- References -- Chapter 9: The Production of Ammonia by Multiheme Cytochromes c. , 1 Introduction.
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  • 3
    ISSN: 1365-2958
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Notizen: Wolinella succinogenes can grow by anaerobic respiration with nitrate or nitrite using formate as electron donor. Two forms of nitrite reductase were isolated from the membrane fraction of W. succinogenes. One form consisted of a 58 kDa polypeptide (NrfA) that was identical to the periplasmic nitrite reductase. The other form consisted of NrfA and a 22 kDa polypeptide (NrfH). Both forms catalysed nitrite reduction by reduced benzyl viologen, but only the dimeric form catalysed nitrite reduction by dimethylnaphthoquinol. Liposomes containing heterodimeric nitrite reductase, formate dehydrogenase and menaquinone catalysed the electron transport from formate to nitrite; this was coupled to the generation of an electrochemical proton potential (positive outside) across the liposomal membrane. It is concluded that the electron transfer from menaquinol to the catalytic subunit (NrfA) of W. succinogenes nitrite reductase is mediated by NrfH. The structural genes nrfA and nrfH were identified in an apparent operon (nrfHAIJ) with two additional genes. The gene nrfA encodes the precursor of NrfA carrying an N-terminal signal peptide (22 residues). NrfA (485 residues) is predicted to be a hydrophilic protein that is similar to the NrfA proteins of Sulfurospirillum deleyianum and of Escherichia coli. NrfH (177 residues) is predicted to be a membrane-bound tetrahaem cytochrome c belonging to the NapC/NirT family. The products of nrfI and nrfJ resemble proteins involved in cytochrome c biogenesis. The C-terminal third of NrfI (902 amino acid residues) is similar to CcsA proteins from Gram-positive bacteria, cyanobacteria and chloroplasts. The residual N-terminal part of NrfI resembles Ccs1 proteins. The deduced NrfJ protein resembles the thioredoxin-like proteins (ResA) of Helicobacter pylori and of Bacillus subtilis, but lacks the common motif CxxC of ResA. The properties of three deletion mutants of W. succinogenes (ΔnrfJ,ΔnrfIJ and ΔnrfAIJ) were studied. Mutants ΔnrfAIJ and ΔnrfIJ did not grow with nitrite as terminal electron acceptor or with nitrate in the absence of NH4+ and lacked nitrite reductase activity, whereas mutant ΔnrfJ showed wild-type properties. The NrfA protein formed by mutant ΔnrfIJ seemed to lack part of the haem C, suggesting that NrfI is involved in NrfA maturation.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    [s.l.] : Macmillan Magazines Ltd.
    Nature 400 (1999), S. 476-480 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] The enzyme cytochrome c nitrite reductase catalyses the six-electron reduction of nitrite to ammonia as one of the key stepsin the biological nitrogen cycle, where it participates inthe anaerobic energy metabolism of dissimilatory nitrate ammonification. Here we report on the crystal structure ...
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 56 (2000), S. 1673-1675 
    ISSN: 1399-0047
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Notizen: A group of anaerobic microorganisms use sulfate as the terminal electron acceptor for energy conservation. The process of sulfate reduction involves several enzymatic steps. One of them is the conversion of adenylyl sulfate (adenosine-5′-phosphosulfate) to sulfite, catalyzed by adenylylsulfate reductase. This enzyme is composed of a FAD-containing α-subunit and a β-subunit harbouring two [4Fe–4S] clusters. Adenylylsulfate reductase was isolated from Archaeoglobus fulgidus under anaerobic conditions and crystallized using the hanging-drop vapour-diffusion method using PEG 4000 as precipitant. The crystals grew in space group P212121, with unit-cell parameters a = 72.4, b = 113.2, c = 194.0 Å. The asymmetric unit probably contains two αβ units. The crystals diffract beyond 2 Å resolution and are suitable for X-ray structure analysis.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    BioMetals 4 (1991), S. 119-125 
    ISSN: 1572-8773
    Schlagwort(e): Bacterial hemoglobin ; Oxygenated hemoglobin ; High- and low-spin hemoglobin ; NADH-dependent hemoglobin reductase ; Iron superoxide dismutase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Vitreoscilla contained a homodimeric bacterial hemoglobin (VtHb). The purification of this protein yielded VtmetHb which exhibited electronic and electron paramagnetic resonance (EPR) spectra, showing that it existed predominantly in a high-spin ferric form, both axial and rhombic components being present. The preparations also contained variable amounts of low-spin components. There was no evidence that these high-spin and low-spin forms were in equilibrium. The former were reducible by NADH catalyzed by the NADH-metVtHb reductase, and the latter were not. High ionic strength and high pH led to the formation of low-spin metVtHb; both treatments were reversible. Cyanide and imidazole liganded to VtHb resulted in the conversion of high-spin to low-spin ferric heme centers, each with characteristic electronic and EPR spectra. Some preparations of VtHb exhibited EPR signals consistent with a sulfur ligand bound to the ferric site. When VtHb was treated with NADH plus the reductase in the presence of oxygen, the intensity of the high-spin EPR signals decreased significantly. No reduction occurred in the absence of oxygen, suggesting a possible role for the superoxide anion. Dithionite treatment of VtHb resulted in a slow reduction, but the main product of the reaction of dithionite-reduced VtHb with oxygen was VtmetHb, not VtHbO2. EPR spectra of whole cells ofVitreoscilla exhibited a variety of intense signals at low and high magnetic field, theg-values being consistent with the presence of high-spin ferric heme proteins, in addition to an iron-containing superoxide dismutase (FeSOD) and iron-sulfur proteins. EPR spectra of the cytosol fraction ofVitreoscilla showed the expected resonances for VtmetHb and FeSOD.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 156 (1991), S. 70-74 
    ISSN: 1432-072X
    Schlagwort(e): Nitrige reductase ; Hexaheme cytochrome c ; “Spirillum” strain 5175 ; Dissimilatory nitrate reduction to ammonia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract When grown with nitrate as terminal electron acceptor both the soluble (periplasm, cytoplasm) and the membrane fraction of “Spirillum” strain 5175 exhibited high nitrite reductase activity. The nitrite reductase obtained from the soluble fraction was purified 76-fold to electrophoretical homogeneity. The enzyme reduced nitrite to ammonia with a specific activity of 723 μmol NO inf2 sup- × (mg protein × min)-1. The molecular mass was 58±1 kDa by SDS-PAGE compared to 59±2 kDa determined by size exclusion chromatography under nondenaturing conditions. The enzyme (as isolated) contained 5.97±0.15 heme c molecules/Mr 58 kDa. The absorption spectrum was typical for c-type cytochrome with maxima at 280, 408, 532 and 610 nm (oxidized) and at 420, 523 and 553 nm (dithionite-reduced). The enzyme (as isolated) exhibited a complex set of high-spin and lowspin ferric heme resonances with g-values at 9.82, 3,85, 3.31, 2.95, 2.30 and 1.49 in agreement with data reported for electron paramagnetic resonance spectra of nitrite reductases from Desulfovibrio desulfuricans, Wolinella succinogenes and Escherichia coli.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-072X
    Schlagwort(e): Key words Sulfide oxidation ; Nitrate ammonification ; Sulfur respiration ; Sulfur reductase ; Sulfurospirillum deleyianum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Sulfurospirillum deleyianum grew in batch culture under anoxic conditions with sulfide (up to 5 mM) as electron donor, nitrate as electron acceptor, and acetate as carbon source. Nitrate was reduced to ammonia via nitrite, a quantitatively liberated intermediate. Four moles of sulfide were oxidized to elemental sulfur per mole nitrate converted to ammonia. The molar growth yield per mole sulfide consumed, Ym, was 1.5 ± 0.2 g mol–1 for the reduction of nitrate to ammonia. By this type of metabolism, S. deleyianum connected the biogeochemical cycles of sulfur and nitrogen. The sulfur reductase activity in S. deleyianum was inducible, as the activity depended on the presence of sulfide or elemental sulfur during cultivation with nitrate or fumarate as electron acceptor. Hydrogenase activity was always high, indicating that the enzyme is constitutively expressed. The ammonia-forming nitrite reductase was an inducible enzyme, expressed when cells were cultivated with nitrate, nitrite, or elemental sulfur, but repressed after cultivation with fumarate.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 158 (1992), S. 127-131 
    ISSN: 1432-072X
    Schlagwort(e): Nitrite oxidation ; Nitrate reduction ; Molybdo-iron-sulfur protein ; Molybdenum center ; Iron-sulfur cluster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nitrite oxidoreductase was isolated from mixotrophically grown cells of Nitrobacter hamburgensis. The enzyme purified from heat treated membranes was homogeneous by the criteria of polyacrylamide gel electrophoresis and size exclusion chromatography. The monomeric form consisted of two subunits with Mr 115000 and 65000, respectively. The dimeric form of the enzyme contained 0.70 molybdenum, 23.0 iron, 1.76 zinc, and 0.89 copper. The catalytically active enzyme was investigated by visible and electron paramagnetic resonance spectroscopy (EPR) under oxidizing (as isolated), reducing (dithionite), and turnover (nitrite) conditions. As isolated the enzyme exhibited a complex set of EPR signals between 5–75 K, originating from several ironsulfur and molybdenum (V) centers. Addition of the substrate nitrite, or the reducing agent dithionite resulted in a set of new resonances. The molybdenum and the iron-sulfur centers of nitrite oxidoreductase from Nitrobacter hamburgensis were involved in the transformation of nitrite to nitrate.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 158 (1992), S. 287-293 
    ISSN: 1432-072X
    Schlagwort(e): Reduction of sulfur ; Sulfide oxidation ; Microaerobic growth ; “Spirillum” 5175 ; Sulfurospirillum deleyianum ; Wolinella succinogenes ; Campylobacter spec
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Physiological tests, redetermination of G+C values with HPLC and DNA-DNA hybridization were used to determine the taxonomic affiliation of “Spirillum” 5175. This facultatively sulfur-reducing bacterium was compared to the type strains of the phenotypically most similar species Wolinella succinogenes and Campylobacter sputorum biovar bubulus. In addition to morphology, the following physiological properties were in common: use of elemental sulfur, nitrate, nitrite, aspartate, fumarate or malate as electron acceptor for growth with hydrogen or formate under anoxic conditions; microaerobic growth with 2% (v/v) oxygen. The G+C content of Wolinella succinogenes (51.8 mol%) and Campylobacter sputorum biovar bubulus (30.4 mol%) differs about 10 mol% from the G+C content of “Spirillum” 5175 (40.6 mol%). No significant DNA homology could be detected between the three strains. These differences excluded affiliation of “Spirillum” 5175 with the genera Wolinella or Campylobacter despite phenotypic similarities. On the basis of our results and DNA-rRNA hybridization studies by other authors, we established the new genus Sulfurospirillum for the freeliving Campylobacter-like bacteria “Spirillum” 5175 and “Campylobacter spec.” DSM 806. Strain “Spirillum” 5175 is described as the type strain of the new genus and species Sulfurospirillum deleyianum.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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