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1.
The three classes of hydrogenases from sulfate-reducing bacteria of the genus Desulfovibrio 总被引:12,自引:0,他引:12
G Fauque H D Peck J J Moura B H Huynh Y Berlier D V DerVartanian M Teixeira A E Przybyla P A Lespinat I Moura 《FEMS microbiology reviews》1988,4(4):299-344
Three types of hydrogenases have been isolated from the sulfate-reducing bacteria of the genus Desulfovibrio. They differ in their subunit and metal compositions, physico-chemical characteristics, amino acid sequences, immunological reactivities, gene structures and their catalytic properties. Broadly, the hydrogenases can be considered as 'iron only' hydrogenases and nickel-containing hydrogenases. The iron-sulfur-containing hydrogenase ([Fe] hydrogenase) contains two ferredoxin-type (4Fe-4S) clusters and an atypical iron-sulfur center believed to be involved in the activation of H2. The [Fe] hydrogenase has the highest specific activity in the evolution and consumption of hydrogen and in the proton-deuterium exchange reaction and this enzyme is the most sensitive to CO and NO2-. It is not present in all species of Desulfovibrio. The nickel-(iron-sulfur)-containing hydrogenases [( NiFe] hydrogenases) possess two (4Fe-4S) centers and one (3Fe-xS) cluster in addition to nickel and have been found in all species of Desulfovibrio so far investigated. The redox active nickel is ligated by at least two cysteinyl thiolate residues and the [NiFe] hydrogenases are particularly resistant to inhibitors such as CO and NO2-. The genes encoding the large and small subunits of a periplasmic and a membrane-bound species of the [NiFe] hydrogenase have been cloned in Escherichia (E.) coli and sequenced. Their derived amino acid sequences exhibit a high degree of homology (70%); however, they show no obvious metal-binding sites or homology with the derived amino acid sequence of the [Fe] hydrogenase. The third class is represented by the nickel-(iron-sulfur)-selenium-containing hydrogenases [( NiFe-Se] hydrogenases) which contain nickel and selenium in equimolecular amounts plus (4Fe-4S) centers and are only found in some species of Desulfovibrio. The genes encoding the large and small subunits of the periplasmic hydrogenase from Desulfovibrio (D.) baculatus (DSM 1743) have been cloned in E. coli and sequenced. The derived amino acid sequence exhibits homology (40%) with the sequence of the [NiFe] hydrogenase and the carboxy-terminus of the gene for the large subunit contains a codon (TGA) for selenocysteine in a position homologous to a codon (TGC) for cysteine in the large subunit of the [NiFe] hydrogenase. EXAFS and EPR studies with the 77Se-enriched D. baculatus hydrogenase indicate that selenium is a ligand to nickel and suggest that the redox active nickel is ligated by at least two cysteinyl thiolate and one selenocysteine selenolate residues.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
2.
An indirect enzyme-linked immunoadsorption assay (ELISA) was developed for cytochrome c3 using antisera to the cytochromes fromDesulfovibrio africanus Benghazi, Desulfovibrio vulgaris Hildenborough andDesulfovibrio salexigens British Guiana. The ELISA system was used to test for cross-reactions between these antisera and the heterologous antigens. In contrast to previous experiments using the Ouchterlony technique, all of the cytochromes c3 tested exhibited some degree of cross-reaction. Considerable variation was seen in cross-reactions for cytochromes c3 from differing strains ofD. desulfuricans. This observation raises questions about the taxonomic relatedness of these strains. No cross-reaction was seen with eukaryotic cytochrome c or withD. vulgaris cytochrome c553. The data demonstrate that cytochrome c3 is capable of undergoing nonprecipitating cross-reactions, and thus may not be as immunologically unique as was once thought.Abbreviations ELISA
Enzyme-linked immunoadsorption assay 相似文献
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4.
Chihiro Azai Yusuke Tsukatani Shigeru Itoh Hirozo Oh-oka 《Photosynthesis research》2010,104(2-3):189-199
Green sulfur bacteria and heliobacteria are strictly anaerobic phototrophs that have homodimeric type 1 reaction center complexes. Within these complexes, highly reducing substances are produced through an initial charge separation followed by electron transfer reactions driven by light energy absorption. In order to attain efficient energy conversion, it is important for the photooxidized reaction center to be rapidly rereduced. Green sulfur bacteria utilize reduced inorganic sulfur compounds (sulfide, thiosulfate, and/or sulfur) as electron sources for their anoxygenic photosynthetic growth. Membrane-bound and soluble cytochromes c play essential roles in the supply of electrons from sulfur oxidation pathways to the P840 reaction center. In the case of gram-positive heliobacteria, the photooxidized P800 reaction center is rereduced by cytochrome c-553 (PetJ) whose N-terminal cysteine residue is modified with fatty acid chains anchored to the cytoplasmic membrane. 相似文献
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6.
Hannebachite (CaSO3 x 0.5H2O), gypsum (CaSO4 x 2H2O), anglesite (PbSO4), and barite (BaSO4) were tested as electron acceptors for sulfate-reducing bacteria with lactate as the electron donor. Hannebachite and gypsum are commonly associated with flue gas desulfurization products, and anglesite is a weathering product found in lead mines. Barite was included as the most insoluble sulfate. Growth of sulfate-reducing bacteria was monitored by protein and sulfide (dissolved H2S and HS-) measurements. Biogenic sulfide formation occurred with all four solid phases, and protein data confirmed that bacteria grew under these electron acceptor conditions. Sulfide formation from gypsum was almost comparable in rate and quantity to that produced from soluble sulfate salt (Na2SO4); hannebachite reduction to sulfide was not as fast. Anglesite as the electron acceptor was also reduced to sulfide in the solution phase and galena (PbS) was detected in solids retrieved from spent cultures. Barite as the electron acceptor supported the least amount of growth and H2S formation. The results demonstrate that low-solubility crystalline phases can be biologically reactive under reducing conditions. Furthermore, the results demonstrate that galena precipitation through sulfide production by sulfate-reducing bacteria serves as a lead enrichment mechanism, thereby also alleviating the potential toxicity of lead. In view of the role of acidophilic thiobacilli in the oxidation of sulfides, the present work accentuates the role of anaerobic and aerobic microbes in the biogeochemical cycling of solid-phase sulfates and sulfides. 相似文献
7.
In this paper, graphite felts were continuously electrochemically oxidized to increase the current generation in microbial fuel cells (MFCs). The treated and untreated graphite felts were utilized as anodes in MFCs and current production was compared. The current production on electrochemically treated graphite felt anodes was about 1.13 mA, 39.5% higher compared with that of MFCs containing untreated anodes. The results demonstrated that the electronic coupling between graphite felt electrodes and electrogenic bacteria could be enhanced by electrochemical oxidization of the electrodes. Further study showed that the newly generated carboxyl containing functional groups from electrochemical oxidization were responsible for the enhanced electron transfer, due to their strong hydrogen bonding with peptide bonds in bacterial cytochromes. 相似文献
8.
A simple mathematical model of electron flow along the mitochondrial respiratory cytochrome assembly and the transfer of electrons to molecular oxygen is presented. First, an expression for the current-voltage relationship for a biological oxygen electrode is derived, and from this the relationship between oxygen consumption rate and oxygen partial pressure is determined. An independent relationship between mitochondrial oxygen partial pressure and oxygen supply rate is then derived. By eliminating oxygen partial pressure from these two expressions, we may obtain a relationship between oxygen supply rate and oxygen consumption rate. This model is then used to investigate the effects of tissue dysoxia, uncoupling of oxidative phosphorylation, increased cellular diffusional resistance and inhomogeneities in oxygen supply on oxygen consumption. It is concluded that each of the above contribute in varying degrees to the phenomenon of "pathological oxygen supply dependency". 相似文献
9.
The rates of electron transfer to P700 from plastocyanin and cytochrome f have been compared with those from three other c-type cytochromes and azurin, a copper protein resembling plastocyanin. Three different disruptive techniques were used to expose P700; digitonin, Triton X-100 and sonication. The following rate constants were measured at 25 °C, pH 7.0, with digitonin-treated chloroplasts: plastocyanin, 8 · 107 M?1 · s?1; red-algal cytochrome c-553, 1.9 · 107 M?1 · s?1; Pseudomonas cytochrome c-551, 8 · 106 M?1 · s?1; azurin, ? 3 · 105 M?1 · s?1; cytochrome f, ? 2 · 104 M?1 · s?1; mammalian cytochrome c, ? 2 · 104 M?1 · s?1. For electron transfer from plastocyanin, the effects of ionic strength, pH and temperature were also studied, and saturation effects found in earlier work were avoided by a full consideration of the various secondary reactions and inclusion of superoxide dismutase. The relative rates are discussed in relation to photosynthetic electron transport. 相似文献
10.
Function of periplasmic hydrogenases in the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough
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Caffrey SM Park HS Voordouw JK He Z Zhou J Voordouw G 《Journal of bacteriology》2007,189(17):6159-6167
The sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough possesses four periplasmic hydrogenases to facilitate the oxidation of molecular hydrogen. These include an [Fe] hydrogenase, an [NiFeSe] hydrogenase, and two [NiFe] hydrogenases encoded by the hyd, hys, hyn1, and hyn2 genes, respectively. In order to understand their cellular functions, we have compared the growth rates of existing (hyd and hyn1) and newly constructed (hys and hyn-1 hyd) mutants to those of the wild type in defined media in which lactate or hydrogen at either 5 or 50% (vol/vol) was used as the sole electron donor for sulfate reduction. Only strains missing the [Fe] hydrogenase were significantly affected during growth with lactate or with 50% (vol/vol) hydrogen as the sole electron donor. When the cells were grown at low (5% [vol/vol]) hydrogen concentrations, those missing the [NiFeSe] hydrogenase suffered the greatest impairment. The growth rate data correlated strongly with gene expression results obtained from microarray hybridizations and real-time PCR using mRNA extracted from cells grown under the three conditions. Expression of the hys genes followed the order 5% hydrogen>50% hydrogen>lactate, whereas expression of the hyd genes followed the reverse order. These results suggest that growth with lactate and 50% hydrogen is associated with high intracellular hydrogen concentrations, which are best captured by the higher activity, lower affinity [Fe] hydrogenase. In contrast, growth with 5% hydrogen is associated with a low intracellular hydrogen concentration, requiring the lower activity, higher affinity [NiFeSe] hydrogenase. 相似文献
11.
Alcaligenes eutrophus strains H 16, B 19, G 27 and N9A contained two different hydrogenases. One enzyme catalyzed the reduction of NAD by hydrogen and was strictly localized in the soluble cell fraction, while the second enzyme was found to be particulate and unable to react with NAD.All other tested strains, Alcaligenes paradoxus SA 29, Pseudomonas facilis, P. palleronii RH 2, Pseudomonas sp. strain GA 3, Paracoccus denitrificans, Aquaspirillum autotrophicum SA 32, and Corynebacterium autotrophicum 14g and 7C contained only a single enzyme exclusively bound to membranes. This was established using fractional centrifugation, indicator enzyme systems, gentle methods of cell disintegration and discontinuous sucrose density gradient centrifugation. In cell-free extracts obtained by rough disruption (sonication) of cells, hydrogenase was associated to particles of different size and sedimentation velocity. A partial solubilization of hydrogenase caused by sonication was observed with P. facilis.Without exception, the particulate hydrogenases were found (1) to be unable to reduce pyridine nucleotides, and (2) to reduce methylene blue at an extremely high activity. The eminent reaction rate of 34 moles H2 oxidized per min and mg protein has been determined in particle suspensions of Pseudomonas sp. strain GA 3. All hydrogenases were stable during storage under hydrogen atmosphere, except the soluble enzyme from A. eutrophus H 16 which was shown to be more stable under aerobic conditions. 相似文献
12.
Abstract Sulfate-reducing bacteria were enumerated in soils and water samples from Senegal ricefields using lactate and sulfate as substrates. When rice plants were severely injured by sulfides, maximum densities ranged from 107 to 109 bacteria g−1 of dry spermosphere or rhizosphere soil. Seven non-sporulating, mesophilic strains were isolated. The strains had motile curved cells and stained Gram-negative. Lactate, pyruvate, H2 + CO2 , malate, fumarate, or ethanol could serve as electron donors. Organic acids were incompletely oxidized to acetate. Alcohols were degraded to the corresponding fatty acids. Sulfate, sulfite, or thiosulfate could serve as electron acceptors and were reduced to sulfide. Vitamins, yeast extract, Biotrypcase, or additional NaCl were not required for growth. On the basis of morphological and physiological properties, and the G + C mol % of the DNA, six isolates were identified as Desulfovibrio vulgaris and one as Desulfovibrio desulfuricans . The comparison of their main physiological properties with the physico-chemical properties of sampling sites indicated that they were better adapted to conditions prevailing in the rice rhizosphere than to those prevailing in the bulk of soil. 相似文献
13.
Electron transfer from periplasmic cytochromes c to the membrane-bound respiratory chain has been studied with the isolated cytochromes and membrane preparations from Paracoccus denitrificans. When reduced cytochromes were incubated with spheroplasts only the constitutive cytochrome c-550 was rapidly oxidized. The inducible cytochromes c-551i and c-553i were not oxidized at appreciable rates. Cytochrome c-550 was able to mediate the transfer of electrons from either cytochrome c-551i or cytochrome c-553i to the membrane preparation. 相似文献
14.
A kinetic perspective on extracellular electron transfer by anode-respiring bacteria 总被引:1,自引:0,他引:1
César I. Torres rew Kato Marcus Hyung-Sool Lee Prathap Parameswaran Rosa Krajmalnik-Brown & Bruce E. Rittmann 《FEMS microbiology reviews》2010,34(1):3-17
In microbial fuel cells and electrolysis cells (MXCs), anode-respiring bacteria (ARB) oxidize organic substrates to produce electrical current. In order to develop an electrical current, ARB must transfer electrons to a solid anode through extracellular electron transfer (EET). ARB use various EET mechanisms to transfer electrons to the anode, including direct contact through outer-membrane proteins, diffusion of soluble electron shuttles, and electron transport through solid components of the extracellular biofilm matrix. In this review, we perform a novel kinetic analysis of each EET mechanism by analyzing the results available in the literature. Our goal is to evaluate how well each EET mechanism can produce a high current density (>10 A m−2 ) without a large anode potential loss (less than a few hundred millivolts), which are feasibility goals of MXCs. Direct contact of ARB to the anode cannot achieve high current densities due to the limited number of cells that can come in direct contact with the anode. Slow diffusive flux of electron shuttles at commonly observed concentrations limits current generation and results in high potential losses, as has been observed experimentally. Only electron transport through a solid conductive matrix can explain observations of high current densities and low anode potential losses. Thus, a study of the biological components that create a solid conductive matrix is of critical importance for understanding the function of ARB. 相似文献
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Anaerobes response to oxygen: the sulfate-reducing bacteria 总被引:4,自引:0,他引:4
17.
Hydrogen as an electron donor for sulfate-reducing bacteria in slurries of salt marsh sediment 总被引:2,自引:0,他引:2
Experiments with a Warburg respirometer showed that a sediment slurry consumed hydrogen from a hydrogen atmosphere, and this
consumption was not due to the activity of methanogenic bacteria. The hydrogren uptake was inhibited by the addition of 20
mM molybdate. Further experiments with sediment slurry held in conical flasks under an atmosphere of nitrogen showed that
hydrogen accumulated in the headspace when bacterial sulfate reduction was inhibited either by the addition of 20 mM molybdate
or by low (<5 mM) sulfate concentrations in the slurry. Methanogenesis was stimulated in the presence of a hydrogen atmosphere
or by the addition of 20 mM molybdate. The results confirmed that hydrogren was an important electron donor for sulfate-reducing
bacteria present in the sediment. The stimulation of methanogenesis by molybdate could be explained in part by a competition
for hydrogen between sulfate-reducing bacteria and hydrogen-metabolizing methanogenic bacteria, but competition for another
common substrate, possibly acetate, could also be significant. 相似文献
18.
B P Atanasov M I Mitovska I N Mancheva G P Kossekova B P Tchorbanov P Christova K I Dancheva 《Biochimica et biophysica acta》1984,765(3):329-339
The preparation, purification and characterization of the three singly, three doubly and one triply substituted derivatives of cytochrome c modified by pyridoxal phosphate (PLP) at lysine residues are reported. The PLP positions in PLP derivatives were determined by the amino acid analysis and sequence of PLP peptides. The results identified the lysine at position 86 in one of the singly substituted, lysine 79 in the other singly substituted and lysines 86 and 79 in the third doubly substituted cytochrome c derivatives. The area surrounding phenylalanine 82 forms the predominant PLP binding site on the cytochrome c molecule. The visible, CD and proton NMR spectra, the full intensity of the conformation-sensitive 695 nm band and the oxidation-reduction properties provide evidence to confirm the conclusion that singly and doubly substituted PLP cytochromes c retain the native conformation. The ability to restore both succinate and ascorbate/TMPD oxidation in cytochrome c-depleted mitochondria decreases in the order: native cytochrome c greater than PLP-Lys-79-cytochrome c greater than PLP-Lys-86-cytochrome c greater than PLP-Lys-79,86-cytochrome c greater than triply substituted derivative. 相似文献
19.
Electrostatic interactions during electron transfer reactions between c-type cytochromes and flavodoxin 总被引:1,自引:0,他引:1
The interaction of three different c-type cytochromes with flavodoxin has been studied by computer graphics modelling and computational methods. Flavodoxin and each cytochrome can make similar hypothetical electron transfer complexes that are characterized by nearly coplanar arrangement of the prosthetic groups, close intermolecular contacts at the protein-protein interface, and complementary intermolecular salt linkages. Computation of the electrostatic free energy of each complex showed that all were electrostatically stable. However, both the magnitude and behavior of the electrostatic stabilization as a function of solution ionic strength differed for the three cytochrome c-flavodoxin complexes. Variation in the computed electrostatic stabilization appears to reflect differences in the surface distribution of all charged groups in the complex, rather than differences localized at the site of intermolecular contact. The computed electrostatic association constants for the complexes and the measured kinetic rates of electron transfer in solution show a remarkable similarity in their ionic strength dependence. This correlation suggests electrostatic interactions influence electron transfer rates between protein molecules at the intermolecular association step. Comparative calculations for the three cytochrome c-flavodoxin complexes show that these ionic strength effects also involve all charged groups in both redox partners. 相似文献
20.
Firer-Sherwood MA Bewley KD Mock JY Elliott SJ 《Metallomics : integrated biometal science》2011,3(4):344-348
Examining electron transfer between two proteins with identical spectroscopic signatures is a challenging task. It is supposed that several multiheme cytochromes in Shewanella oneidensis form a molecular "wire" through which electrons are transported across the cellular space and a direct study of this transient protein-protein interaction has not yet been reported. In this study, we present variations on catalytic protein film voltammetry and an anaerobic affinity chromatography assay to demonstrate unidirectional electron transfer between proposed protein pairs. Through use of these techniques, we are able to confirm the transient interactions between these cytochromes, supporting the model of electron transfer that is present in the literature. 相似文献