A new water-soluble bacterial NADH: fumarate oxidoreductase

ABSTRACT The cytoplasmic fumarate reductase of Klebsiella pneumoniae (FRD) is a monomeric protein which contains three prosthetic groups: noncovalently bound FMN and FAD plus a covalently bound FMN. In the present work, NADH is revealed to be an inherent electron donor for this enzyme. We found that the fumarate reductase activity of FRD significantly exceeds its NADH dehydrogenase activity. During the catalysis of NADH:fumarate oxidoreductase reaction, FRD turnover is limited by a very low rate (∼10/s) of electron transfer between the noncovalently and covalently bound FMN moieties. Induction of FRD synthesis in K. pneumoniae cells was observed only under anaerobic conditions in the presence of fumarate or malate. Enzymes with the FRD-like domain architecture are widely distributed among various bacteria and apparently comprise a new type of water-soluble NADH:fumarate oxidoreductases.

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Chromate Reduction by a Pseudomonad Isolated from a Site Contaminated with Chromated Copper Arsenate

Applied and Environmental Microbiology ◽

10.1128/aem.67.3.1076-1084.2001 ◽

2001 ◽

Vol 67 (3) ◽

pp. 1076-1084 ◽

Cited By ~ 255

Author(s):

Jeff McLean ◽

Terry J. Beveridge

Keyword(s):

Reductase Activity ◽

Wood Preservation ◽

Chromate Reduction ◽

Anaerobic Conditions ◽

Toxic Heavy Metal ◽

Metal Metal ◽

A Site ◽

Anaerobic Reduction ◽

Aerobic And Anaerobic ◽

Aerobic And Anaerobic Conditions

ABSTRACT A pseudomonad (CRB5) isolated from a decommissioned wood preservation site reduced toxic chromate [Cr(VI)] to an insoluble Cr(III) precipitate under aerobic and anaerobic conditions. CRB5 tolerated up to 520 mg of Cr(VI) liter−1 and reduced chromate in the presence of copper and arsenate. Under anaerobic conditions it also reduced Co(III) and U(VI), partially internalizing each metal. Metal precipitates were also found on the surface of the outer membrane and (sometimes) on a capsule. The results showed that chromate reduction by CRB5 was mediated by a soluble enzyme that was largely contained in the cytoplasm but also found outside of the cells. The crude reductase activity in the soluble fraction showed aKm of 23 mg liter−1 (437 μM) and a V max of 0.98 mg of Cr h−1 mg of protein−1 (317 nmol min−1 mg of protein−1). Minor membrane-associated Cr(VI) reduction under anaerobiosis may account for anaerobic reduction of chromate under nongrowth conditions with an organic electron donor present. Chromate reduction under both aerobic and anaerobic conditions may be a detoxification strategy for the bacterium which could be exploited to bioremediate chromate-contaminated or other toxic heavy metal-contaminated environments.

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Anaerobic NADH-Fumarate Reductase System Is Predominant in the Respiratory Chain of Echinococcus multilocularis, Providing a Novel Target for the Chemotherapy of Alveolar Echinococcosis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00378-07 ◽

2007 ◽

Vol 52 (1) ◽

pp. 164-170 ◽

Cited By ~ 40

Author(s):

Jun Matsumoto ◽

Kimitoshi Sakamoto ◽

Noriko Shinjyo ◽

Yasutoshi Kido ◽

Nao Yamamoto ◽

...

Keyword(s):

Respiratory Chain ◽

Echinococcus Multilocularis ◽

Alveolar Echinococcosis ◽

Reductase Activity ◽

Mitochondrial Respiratory Chain ◽

Quinone Reductase ◽

Fumarate Reductase ◽

Electron Mediator ◽

Mitochondrial Fractions ◽

Mitochondrial Respiratory

ABSTRACT Alveolar echinococcosis, which is due to the massive growth of larval Echinococcus multilocularis, is a life-threatening parasitic zoonosis distributed widely across the northern hemisphere. Commercially available chemotherapeutic compounds have parasitostatic but not parasitocidal effects. Parasitic organisms use various energy metabolic pathways that differ greatly from those of their hosts and therefore could be promising targets for chemotherapy. The aim of this study was to characterize the mitochondrial respiratory chain of E. multilocularis, with the eventual goal of developing novel antiechinococcal compounds. Enzymatic analyses using enriched mitochondrial fractions from E. multilocularis protoscoleces revealed that the mitochondria exhibited NADH-fumarate reductase activity as the predominant enzyme activity, suggesting that the mitochondrial respiratory system of the parasite is highly adapted to anaerobic environments. High-performance liquid chromatography-mass spectrometry revealed that the primary quinone of the parasite mitochondria was rhodoquinone-10, which is commonly used as an electron mediator in anaerobic respiration by the NADH-fumarate reductase system of other eukaryotes. This also suggests that the mitochondria of E. multilocularis protoscoleces possess an anaerobic respiratory chain in which complex II of the parasite functions as a rhodoquinol-fumarate reductase. Furthermore, in vitro treatment assays using respiratory chain inhibitors against the NADH-quinone reductase activity of mitochondrial complex I demonstrated that they had a potent ability to kill protoscoleces. These results suggest that the mitochondrial respiratory chain of the parasite is a promising target for chemotherapy of alveolar echinococcosis.

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Water-soluble hyperbranched polyglycerol photosensitizer for enhanced photodynamic therapy

Polymer Chemistry ◽

10.1039/d0py00431f ◽

2020 ◽

Vol 11 (23) ◽

pp. 3913-3921

Author(s):

Bowen Xiang ◽

Yudong Xue ◽

Zhiyong Liu ◽

Jia Tian ◽

Holger Frey ◽

...

Keyword(s):

Photodynamic Therapy ◽

Water Soluble ◽

One Step ◽

New Type ◽

Hyperbranched Polyglycerol

Herein, we successfully fabricated a new type of water-soluble, hyperbranched polyglycerol photosensitizer through one-step esterification between water-soluble hyperbranched polyglycerol (hbPG) and fluorophenylporphyrin (FP).

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Synthesis and Properties of a Novel Environmentally Friendly Phase Change Energy Storage Coating Additive

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.805-806.1538 ◽

2013 ◽

Vol 805-806 ◽

pp. 1538-1541

Author(s):

Peng Fu ◽

Peng Xi ◽

Fu Lai Zhao ◽

Bo Wen Cheng

Keyword(s):

Energy Storage ◽

Phase Change ◽

Synthesis Method ◽

Waterborne Polyurethane ◽

Water Soluble ◽

Water As Solvent ◽

Soft Segments ◽

New Type ◽

Energy Storage Material ◽

Very High

Waterborne polyurethane (PU) coatings are diluted with water as the medium, without volatile organic solvents and harmful to human body and environment. Adding insulation materials in building individually is a waste of resource. We found a kind of waterborne PU phase change energy storage material easily dissolved and formed film after solvent evaporating having the potential of coating. In this article, we synthesized a new kind of waterborne PU phase change energy storage coating additive via two-step synthesis method, of which a new type of aromatic tetrahydroxycompound (ATTC) is used as branch unit, 4, 4'-diphenylmethanediisocyanate (MDI) and polyethylene glycol (PEG) respectively as hard and soft segments. POM photographs show that the sphaerocrystals of this new coating additive can reach 200-500μm. The crystal structure is characterized by XRD, and the phase change unit is PEG. DSC tests show that the phase change enthalpy value of this coating additive is very high reached more than 90 J/g. The preservation of this water-soluble PU coating is relatively simple, using water as solvent, which can be easy to dissolve in water and form film after water evaporated.

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Purification and characterization of membrane-bound fumarate reductase from anaerobically grown Escherichia coli

Canadian Journal of Biochemistry ◽

10.1139/o79-101 ◽

1979 ◽

Vol 57 (6) ◽

pp. 813-821 ◽

Cited By ~ 49

Author(s):

Peter Dickie ◽

Joel H. Weiner

Keyword(s):

Escherichia Coli ◽

Reductase Activity ◽

Sodium Dodecyl ◽

Gel Filtration ◽

Sodium Cholate ◽

Defined Medium ◽

Exchange Chromatography ◽

Fumarate Reductase ◽

Molar Ratios ◽

Membrane Bound

Fumarate reductase has been purified 100-fold to 95% homogeneity from the cytoplasmic membrane of Escherichia coli, grown anaerobically on a defined medium containing glycerol plus fumarate. Optimal solubilization of total membrane protein and fumarate reductase activity occurred with nonionic detergents having a hydrophobic–lipophilic balance (HLB) number near 13 and we routinely solubilized the enzyme with Triton X-100 (HLB number = 13.5). Membrane enzyme extracts were fractionated by hydrophobic-exchange chromatography on phenyl Sepharose CL-4B to yield purified enzyme. The enzyme, whether membrane bound, in Triton extracts, or purified, had an apparent Km near 0.42 mM. Two peptides with molecular weights of 70 000 and 24 000, present in 1:1 molar ratios, were identified by sodium dodecyl sulfate polyacrylamide slab-gel electrophoresis to coincide with enzyme activity. A minimal native molecular weight of 100 000 was calculated for fumarate reductase by Sephacryl S-200 gel filtration in the presence of sodium cholate. This would indicate that the enzyme is a dimer. The purified enzyme has low, but measurable, succinate dehydrogenase activity.

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Glutathione-dependent activities of Trypanosoma cruzi p52 makes it a new member of the thiol:disulphide oxidoreductase family

Biochemical Journal ◽

10.1042/bj3220043 ◽

1997 ◽

Vol 322 (1) ◽

pp. 43-48 ◽

Cited By ~ 24

Author(s):

Mireille MOUTIEZ ◽

Eric QUÉMÉNEUR ◽

Christian SERGHERAERT ◽

Valérie LUCAS ◽

André TARTAR ◽

...

Keyword(s):

Trypanosoma Cruzi ◽

Active Site ◽

Catalytic Mechanism ◽

Reductase Activity ◽

Redox Balance ◽

Ribonuclease A ◽

Physiological Conditions ◽

Active Site Motif ◽

Key Enzyme ◽

Low Rate

Trypanothione:glutathione disulphide thioltransferase of Trypanosoma cruzi (p52) is a key enzyme in the regulation of the intracellular thiolŐdisulphide redox balance by reducing glutathione disulphide. Here we show that p52, like other disulphide oxidoreductases possessing the CXXC active site motif, catalyses the reduction of low-molecular-mass disulphides (hydroxyethyldisulphide) as well as protein disulphides (insulin). However, p52 seems to be a poor oxidase under physiological conditions as evidenced by its very low rate for oxidative renaturation of reduced ribonuclease A. Like thioltransferase and protein disulphide isomerase, p52 was found to possess a glutathione-dependent dehydroascorbate reductase activity. The kinetic parameters were in the same range as those determined for mammalian dehydroascorbate reductases. A catalytic mechanism taking into account both trypanothione- and glutathione-dependent reduction reactions was proposed. This newly characterized enzyme is specific for the parasite and provides a new target for specific chemotherapy.

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