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Soufian Ouchane - One of the best experts on this subject based on the ideXlab platform.
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Cadmium and Copper Cross-Tolerance. Cu+ Alleviates Cd2 + Toxicity, and Both Cations Target Heme and Chlorophyll Biosynthesis Pathway in Rubrivivax gelatinosus.
Frontiers in microbiology, 2020Co-Authors: Anne Soisig Steunou, Sylviane Liotenberg, Anne Durand, Marie-line Bourbon, Marion Babot, Reem Tambosi, Soufian OuchaneAbstract:Cadmium, although not redox active is highly toxic. Yet, the underlying mechanisms driving toxicity are still to be characterized. In this study, we took advantage of the purple bacterium Rubrivivax gelatinosus strain with defective Cd2 +-efflux system to identify targets of this metal. Exposure of the ΔcadA strain to Cd2 + causes a decrease in the photosystem amount and in the activity of respiratory complexes. As in case of Cu+ toxicity, the data indicated that Cd2 + targets the porphyrin biosynthesis pathway at the level of HemN, a S-adenosylmethionine and CxxxCxxC coordinated [4Fe-4S] containing enzyme. Cd2 + exposure therefore results in a deficiency in heme and chlorophyll dependent proteins and metabolic pathways. Given the importance of porphyrin biosynthesis, HemN represents a key metal target to account for toxicity. In the environment, microorganisms are exposed to mixture of metals. Nevertheless, the biological effects of such mixtures, and the toxicity mechanisms remain poorly addressed. To highlight a potential cross-talk between Cd2 + and Cu+ -efflux systems, we show (i) that Cd2 + induces the expression of the Cd2 +-efflux pump CadA and the Cu+ detoxification system CopA and CopI; and (ii) that Cu+ ions improve tolerance towards Cd2 +, demonstrating thus that metal mixtures could also represent a selective advantage in the environment.
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cadmium and copper cross tolerance cu alleviates cd2 toxicity and both cations target heme and chlorophyll biosynthesis pathway in Rubrivivax gelatinosus
Frontiers in Microbiology, 2020Co-Authors: Anne Soisig Steunou, Sylviane Liotenberg, Anne Durand, Marie-line Bourbon, Marion Babot, Reem Tambosi, Soufian OuchaneAbstract:Cadmium, although not redox active is highly toxic. Yet, the underlying mechanisms driving toxicity are still to be characterized. In this study, we took advantage of the purple bacterium Rubrivivax gelatinosus strain with defective Cd2 +-efflux system to identify targets of this metal. Exposure of the ΔcadA strain to Cd2 + causes a decrease in the photosystem amount and in the activity of respiratory complexes. As in case of Cu+ toxicity, the data indicated that Cd2 + targets the porphyrin biosynthesis pathway at the level of HemN, a S-adenosylmethionine and CxxxCxxC coordinated [4Fe-4S] containing enzyme. Cd2 + exposure therefore results in a deficiency in heme and chlorophyll dependent proteins and metabolic pathways. Given the importance of porphyrin biosynthesis, HemN represents a key metal target to account for toxicity. In the environment, microorganisms are exposed to mixture of metals. Nevertheless, the biological effects of such mixtures, and the toxicity mechanisms remain poorly addressed. To highlight a potential cross-talk between Cd2 + and Cu+ -efflux systems, we show (i) that Cd2 + induces the expression of the Cd2 +-efflux pump CadA and the Cu+ detoxification system CopA and CopI; and (ii) that Cu+ ions improve tolerance towards Cd2 +, demonstrating thus that metal mixtures could also represent a selective advantage in the environment.
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Cadmium and Copper Cross-Tolerance. Cu$^+$ Alleviates Cd$^{2+}$ Toxicity, and Both Cations Target Heme and Chlorophyll Biosynthesis Pathway in $Rubrivivax\ gelatinosus$
Frontiers in Microbiology, 2020Co-Authors: Anne Soisig Steunou, Sylviane Liotenberg, Anne Durand, Marie-line Bourbon, Marion Babot, Reem Tambosi, Soufian OuchaneAbstract:Cadmium, although not redox active is highly toxic. Yet, the underlying mechanisms driving toxicity are still to be characterized. In this study, we took advantage of the purple bacterium Rubrivivax gelatinosus strain with defective Cd2+-efflux system to identify targets of this metal. Exposure of the 1cadA strain to Cd2+ causes a decrease in the photosystem amount and in the activity of respiratory complexes. As in case of Cu+ toxicity, the data indicated that Cd2+ targets the porphyrin biosynthesis pathway at the level of HemN, a S-adenosylmethionine and CxxxCxxC coordinated [4Fe-4S] containing enzyme. Cd2+ exposure therefore results in a deficiency in heme and chlorophyll dependent proteins and metabolic pathways. Given the importance of porphyrin biosynthesis, HemN represents a key metal target to account for toxicity. In the environment, microorganisms are exposed to mixture of metals. Nevertheless, the biological effects of such mixtures, and the toxicity mechanisms remain poorly addressed. To highlight a potential cross-talk between Cd2+ and Cu+ -efflux systems, we show (i) that Cd2+ induces the expression of the Cd2+-efflux pump CadA and the Cu+ detoxification system CopA and CopI; and (ii) that Cu+ ions improve tolerance towards Cd2+, demonstrating thus that metal mixtures could also represent a selective advantage in the environment.
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coproporphyrin iii excretion identifies the anaerobic coproporphyrinogen iii oxidase hemn as a copper target in the cu atpase mutant copa of Rubrivivax gelatinosus
Molecular Microbiology, 2013Co-Authors: Asma Azzouzi, Soufian Ouchane, Chantal Astier, Anne Soisig Steunou, Anne Durand, Marie-line Bourbon, Bahia Khalfaouihassani, David BollivarAbstract:Summary Two genes encoding structurally similar Copper P1B-type ATPases can be identified in several genomes. Notwithstanding the high sequence and structural similarities these ATPases held, it has been suggested that they fulfil distinct physiological roles. In deed, we have shown that the Cu+-ATPase CtpA is required only for the activity of cuproproteins in the purple bacterium Rubrivivax gelatinosus; herein, we show that CopA is not directly required for cytochrome c oxidase but is vital for copper tolerance. Interestingly, excess copper in the copA− mutant resulted in a substantial decrease of the cytochrome c oxidase and the photosystem under microaerobic and anaerobic conditions together with the extrusion of coproporphyrin III. The data indicated that copper targeted the tetrapyrrole biosynthesis pathway at the level of the coproporphyrinogen III oxidase HemN and thereby affects the oxidase and the photosystem. This is the first in vivo demonstration that copper, like oxygen, affects tetrapyrrole biosynthesis presumably at the level of the SAM and [4Fe-4S] containing HemN enzyme. In light of these results and similar findings in Escherichia coli, the potential role of copper ions in the evolution of [4Fe-4S] enzymes and the Cu+-ATPases is discussed.
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EmbRS a new two‐component system that inhibits biofilm formation and saves Rubrivivax gelatinosus from sinking
MicrobiologyOpen, 2013Co-Authors: Anne Soisig Steunou, Chantal Astier, Sylviane Liotenberg, Marie-noëlle Soler, Romain Briandet, Valérie Barbe, Soufian OuchaneAbstract:Photosynthetic bacteria can switch from planktonic lifestyle to phototrophic biofilm in mats in response to environmental changes. The mechanisms of phototrophic biofilm formation are, however, not characterized. Herein, we report a two-component system EmbRS that controls the biofilm formation in a photosynthetic member of the Burkholderiales order, the purple bacterium Rubrivivax gelatinosus. EmbRS inactivation results in cells that form conspicuous bacterial veils and fast-sinking aggregates in liquid. Biofilm analyses indicated that EmbRS represses the production of an extracellular matrix and biofilm formation. Mapping of transposon mutants that partially or completely restore the wild-type (WT) phenotype allowed the identification of two gene clusters involved in polysaccharide synthesis, one fully conserved only in Thauera sp., a floc-forming wastewater bacterium. A second two-component system BmfRS and a putative diguanylate cyclase BdcA were also identified in this screen suggesting their involvement in biofilm formation in this bacterium. The role of polysaccharides in sinking of microorganisms and organic matter, as well as the importance and the evolution of such regulatory system in phototrophic microorganisms are discussed.
Chantal Astier - One of the best experts on this subject based on the ideXlab platform.
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coproporphyrin iii excretion identifies the anaerobic coproporphyrinogen iii oxidase hemn as a copper target in the cu atpase mutant copa of Rubrivivax gelatinosus
Molecular Microbiology, 2013Co-Authors: Asma Azzouzi, Soufian Ouchane, Chantal Astier, Anne Soisig Steunou, Anne Durand, Marie-line Bourbon, Bahia Khalfaouihassani, David BollivarAbstract:Summary Two genes encoding structurally similar Copper P1B-type ATPases can be identified in several genomes. Notwithstanding the high sequence and structural similarities these ATPases held, it has been suggested that they fulfil distinct physiological roles. In deed, we have shown that the Cu+-ATPase CtpA is required only for the activity of cuproproteins in the purple bacterium Rubrivivax gelatinosus; herein, we show that CopA is not directly required for cytochrome c oxidase but is vital for copper tolerance. Interestingly, excess copper in the copA− mutant resulted in a substantial decrease of the cytochrome c oxidase and the photosystem under microaerobic and anaerobic conditions together with the extrusion of coproporphyrin III. The data indicated that copper targeted the tetrapyrrole biosynthesis pathway at the level of the coproporphyrinogen III oxidase HemN and thereby affects the oxidase and the photosystem. This is the first in vivo demonstration that copper, like oxygen, affects tetrapyrrole biosynthesis presumably at the level of the SAM and [4Fe-4S] containing HemN enzyme. In light of these results and similar findings in Escherichia coli, the potential role of copper ions in the evolution of [4Fe-4S] enzymes and the Cu+-ATPases is discussed.
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EmbRS a new two‐component system that inhibits biofilm formation and saves Rubrivivax gelatinosus from sinking
MicrobiologyOpen, 2013Co-Authors: Anne Soisig Steunou, Chantal Astier, Sylviane Liotenberg, Marie-noëlle Soler, Romain Briandet, Valérie Barbe, Soufian OuchaneAbstract:Photosynthetic bacteria can switch from planktonic lifestyle to phototrophic biofilm in mats in response to environmental changes. The mechanisms of phototrophic biofilm formation are, however, not characterized. Herein, we report a two-component system EmbRS that controls the biofilm formation in a photosynthetic member of the Burkholderiales order, the purple bacterium Rubrivivax gelatinosus. EmbRS inactivation results in cells that form conspicuous bacterial veils and fast-sinking aggregates in liquid. Biofilm analyses indicated that EmbRS represses the production of an extracellular matrix and biofilm formation. Mapping of transposon mutants that partially or completely restore the wild-type (WT) phenotype allowed the identification of two gene clusters involved in polysaccharide synthesis, one fully conserved only in Thauera sp., a floc-forming wastewater bacterium. A second two-component system BmfRS and a putative diguanylate cyclase BdcA were also identified in this screen suggesting their involvement in biofilm formation in this bacterium. The role of polysaccharides in sinking of microorganisms and organic matter, as well as the importance and the evolution of such regulatory system in phototrophic microorganisms are discussed.
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EmbRS a new two-component system that inhibits biofilm formation and saves Rubrivivax gelatinosus from sinking
MicrobiologyOpen, 2013Co-Authors: Anne Soisig Steunou, Chantal Astier, Sylviane Liotenberg, Marie-noëlle Soler, Romain Briandet, Valérie Barbe, Soufian OuchaneAbstract:Photosynthetic bacteria can switch from planktonic lifestyle to phototrophic biofilm in mats in response to environmental changes. The mechanisms of phototrophic biofilm formation are, however, not characterized. Herein, we report a two-component system EmbRS that controls the biofilm formation in a photosynthetic member of the Burkholderiales order, the purple bacterium Rubrivivax gelatinosus. EmbRS inactivation results in cells that form conspicuous bacterial veils and fast-sinking aggregates in liquid. Biofilm analyses indicated that EmbRS represses the production of an extracellular matrix and biofilm formation. Mapping of transposon mutants that partially or completely restore the wild-type (WT) phenotype allowed the identification of two gene clusters involved in polysaccharide synthesis, one fully conserved only in Thauera sp., a floc-forming wastewater bacterium. A second two-component system BmfRS and a putative diguanylate cyclase BdcA were also identified in this screen suggesting their involvement in biofilm formation in this bacterium. The role of polysaccharides in sinking of microorganisms and organic matter, as well as the importance and the evolution of such regulatory system in phototrophic microorganisms are discussed.
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Adaptation to Oxygen ROLE OF TERMINAL OXIDASES IN PHOTOSYNTHESIS INITIATION IN THE PURPLE PHOTOSYNTHETIC BACTERIUM, Rubrivivax gelatinosus
The Journal of biological chemistry, 2010Co-Authors: B.k. Hassani, Françoise Reiss-husson, Chantal Astier, Anne Soisig Steunou, Sylviane Liotenberg, Soufian OuchaneAbstract:The appearance of oxygen in the Earth's atmosphere via oxygenic photosynthesis required strict anaerobes and obligate phototrophs to cope with the presence of this toxic molecule. Here we show that in the anoxygenic phototroph Rubrivivax gelatinosus, the terminal oxidases (cbb(3), bd, and caa(3)) expand the range of ambient oxygen tensions under which the organism can initiate photosynthesis. Unlike the wild type, the cbb(3)(-)/bd(-) double mutant can start photosynthesis only in deoxygenated medium or when oxygen is removed, either by sparging cultures with nitrogen or by co-inoculation with strict aerobes bacteria. In oxygenated environments, this mutant survives nonphotosynthetically until the O(2) tension is reduced. The cbb(3) and bd oxidases are therefore required not only for respiration but also for reduction of the environmental O(2) pressure prior to anaerobic photosynthesis. Suppressor mutations that restore respiration simultaneously restore photosynthesis in nondeoxygenated medium. Furthermore, induction of photosystem in the cbb(3)(-) mutant led to a highly unstable strain. These results demonstrate that photosynthetic metabolism in environments exposed to oxygen is critically dependent on the O(2)-detoxifying action of terminal oxidases.
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multiple rieske genes in prokaryotes exchangeable rieske subunits in the cytochrome bc1 complex of Rubrivivax gelatinosus
Molecular Microbiology, 2005Co-Authors: Soufian Ouchane, André Verméglio, Wolfgang Nitschke, Pierre Bianco, Chantal AstierAbstract:Bacterial cytochrome bc 1 -complex encoded by the petABC operon consists of three subunits, the Rieske iron-sulphur protein, the b-type cytochrome, and the c 1 -type cytochrome. Disruption of the petA gene of Rubrivivax gelatinosus is not lethal under photosynthetic growth conditions. However, deletion of both petA and petB results in a photosynthesis-deficient strain, suggesting the presence of a second gene encoding a Rieske protein and rescuing a functional cytochrome bc 1 -complex in the PETA1 mutant. The corresponding petA2 gene was identified and the PETA2 mutant could also grow under photosynthetic conditions. The double mutant PETA12, however, was unable to grow photosynthetically. The presence of a photo-induced cyclic electron transfer was tested by monitoring the kinetics of cytochrome photooxidation on intact cells; the data confirm the capacity of petA2 to replace petA1 in the bc 1 -complex to support photosynthesis. Soluble forms of both PetA1 and PetA2 Rieske proteins were purified from Escherichia coli and found to contain correctly inserted [2Fe-2S] clusters. Electron paramagnetic resonance (EPR) spectroscopy and midpoint potential measurements showed typical [2Fe-2S] signals and E m values of +275 mV for both Rieske proteins. The high amino acid sequence similarity and the obtained midpoint potential values argue for a functional role of these proteins in the cytochrome bc 1 -complex. The presence of duplicated Rieske genes is not restricted to R. gelatinosus. Phylogenetic trees of Rieske genes from Rubrivivax and other proteobacteria as well as from cyanobacteria were reconstructed. On the basis of the phylogenetic analyses, differing evolutionary origins of duplicated Rieske genes in proteo- and cyanobacteria are proposed.
Françoise Reiss-husson - One of the best experts on this subject based on the ideXlab platform.
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Adaptation to Oxygen ROLE OF TERMINAL OXIDASES IN PHOTOSYNTHESIS INITIATION IN THE PURPLE PHOTOSYNTHETIC BACTERIUM, Rubrivivax gelatinosus
The Journal of biological chemistry, 2010Co-Authors: B.k. Hassani, Françoise Reiss-husson, Chantal Astier, Anne Soisig Steunou, Sylviane Liotenberg, Soufian OuchaneAbstract:The appearance of oxygen in the Earth's atmosphere via oxygenic photosynthesis required strict anaerobes and obligate phototrophs to cope with the presence of this toxic molecule. Here we show that in the anoxygenic phototroph Rubrivivax gelatinosus, the terminal oxidases (cbb(3), bd, and caa(3)) expand the range of ambient oxygen tensions under which the organism can initiate photosynthesis. Unlike the wild type, the cbb(3)(-)/bd(-) double mutant can start photosynthesis only in deoxygenated medium or when oxygen is removed, either by sparging cultures with nitrogen or by co-inoculation with strict aerobes bacteria. In oxygenated environments, this mutant survives nonphotosynthetically until the O(2) tension is reduced. The cbb(3) and bd oxidases are therefore required not only for respiration but also for reduction of the environmental O(2) pressure prior to anaerobic photosynthesis. Suppressor mutations that restore respiration simultaneously restore photosynthesis in nondeoxygenated medium. Furthermore, induction of photosystem in the cbb(3)(-) mutant led to a highly unstable strain. These results demonstrate that photosynthetic metabolism in environments exposed to oxygen is critically dependent on the O(2)-detoxifying action of terminal oxidases.
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Characterization of the core complex of Rubrivivax gelatinosus in a mutant devoid of the LH2 antenna.
Biochimica et biophysica acta, 2005Co-Authors: Jean-luc Ranck, Frédéric Halgand, Olivier Laprévote, Françoise Reiss-hussonAbstract:Abstract The core complex of purple bacteria is a supramolecular assembly consisting of an array of light-harvesting LH1 antenna organized around the reaction center. It has been isolated and characterized in this work using a Rubrivivax gelatinosus mutant lacking the peripheral LH2 antenna. The purification did not modify the organization of the complex as shown by comparison with the intact membranes of the mutant. The protein components consisted exclusively of the reaction center, the associated tetraheme cyt c and the LH1 αβ subunits; no other protein which could play the role of pufX could be detected. The complex migrated as a single band in a sucrose gradient, and as a monomer in a native Blue gel electrophoresis. Comparison of its absorbance spectrum with those of the isolated RC and of the LH1 antenna as well as measurements of the bacteriochlorophyll/tetraheme cyt c ratio indicated that the mean number of LH1 subunits per RC-cyt c is near 16. The polypeptides of the LH1 antenna were shown to present several modifications. The α one was formylated at its N-terminal residue and the N-terminal methionine of β was cleaved, as already observed for other Rubrivivax gelatinosus strains. Both modifications occurred possibly by post-translational processing. Furthermore the α polypeptides were heterogeneous, some of them having lost the 15 last residues of their C-terminus. This truncation of the hydrophobic C-terminal extension is similar to that observed previously for the α polypeptide of the Rubrivivax gelatinosus LH2 antenna and is probably due to proteolysis or to instability of this extension.
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Characterization of unusual hydroxy- and ketocarotenoids in Rubrivivax gelatinosus: involvement of enzyme CrtF or CrtA.
Archives of microbiology, 2003Co-Authors: Violaine Pinta, Soufian Ouchane, M Picaud, Chantal Astier, Shinichi Takaichi, Françoise Reiss-hussonAbstract:Carotenoids are widely spread terpenoids found in photosynthetic organisms and a number of non-photosynthetic fungi and bacteria. The photosynthetic non-sulfur purple bacterium Rubrivivax gelatinosus produces carotenoids by both the spheroidene and the normal spirilloxanthin pathways. The characteristics of two carotenogenesis enzymes, spheroidene monooxygenase CrtA and O-methyltransferase CrtF, were investigated. Disruption of the corresponding genes by insertional mutagenesis affected carotenoid species in both pathways, and the genetic evidence indicated that both genes are involved in the two pathways. In these mutants, several unusual hydroxy- and ketocarotenoids were identified by spectroscopic and chemical methods. Moreover, the carotenoid analyses demonstrated that a large number of different carotenoid intermediates are accepted as substrates by the CrtA enzyme. The combined manipulation of crtF and crtA allowed new carotenoids to be produced and broadened the diversity of structurally different carotenoids synthesized by Rvi. gelatinosus. Methylated carotenoids, such as spheroidene and spirilloxanthin, are known to function as accessory pigments in the light-harvesting and reaction-center complexes of purple bacteria; the demethylated carotenoids described here were able to fulfill the same functions in the mutants.
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Two-dimensional structure of the native light-harvesting complex LH2 from Rubrivivax gelatinosus and of a truncated form.
Biochimica et biophysica acta, 2001Co-Authors: Jean-luc Ranck, Teresa Ruiz, Gérard Pehau-arnaudet, Bernadette Arnoux, Françoise Reiss-hussonAbstract:The light-harvesting complex LH2 of Rubrivivax gelatinosus has an oligomeric structure built from α-β heterodimers containing three bacteriochlorophylls and one carotenoid each. The α subunit (71 residues) presents a C-terminal hydrophobic extension (residues 51–71) which is prone to attack by an endogenous protease. This extension can also be cleaved by a mild thermolysin treatment, as demonstrated by electrophoresis and by matrix-assisted laser desorption-time of flight mass spectrometry. This cleavage does not affect the pigment binding sites as shown by absorption spectroscopy. Electron microscopy was used to investigate the structures of the native and thermolysin cleaved forms of the complexes. Two-dimensional crystals of the reconstituted complexes were examined after negative staining and cryomicroscopy. Projection maps at 10 A resolution were calculated, demonstrating the nonameric ring-like organization of α-β subunits. The cleaved form presents the same structural features. We conclude that the LH2 complex is structurally homologous to the Rhodopseudomonas acidophila LH2. The hydrophobic C-terminal extension does not fold back in the membrane, but lays out on the periplasmic surface of the complex.
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High-resolution AFM topographs of Rubrivivax gelatinosus light-harvesting complex LH2
The EMBO journal, 2001Co-Authors: Simon Scheuring, Françoise Reiss-husson, Andreas Engel, Jean-louis Rigaud, Jean-luc RanckAbstract:Light-harvesting complexes 2 (LH2) are the accessory antenna proteins in the bacterial photosynthetic apparatus and are built up of alphabeta-heterodimers containing three bacteriochlorophylls and one carotenoid each. We have used atomic force microscopy (AFM) to investigate reconstituted LH2 from Rubrivivax gelatinosus, which has a C-terminal hydrophobic extension of 21 amino acids on the alpha-subunit. High-resolution topographs revealed a nonameric organization of the regularly packed cylindrical complexes incorporated into the membrane in both orientations. Native LH2 showed one surface which protruded by approximately 6 A and one that protruded by approximately 14 A from the membrane. Topographs of samples reconstituted with thermolysin-digested LH2 revealed a height reduction of the strongly protruding surface to approximately 9 A, and a change of its surface appearance. These results suggested that the alpha-subunit of R.gelatinosus comprises a single transmembrane helix and an extrinsic C-terminus, and allowed the periplasmic surface to be assigned. Occasionally, large rings ( approximately 120 A diameter) surrounded by LH2 rings were observed. Their diameter and appearance suggest the large rings to be LH1 complexes.
Kenji V. P. Nagashima - One of the best experts on this subject based on the ideXlab platform.
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Effects of the deletion of hup genes encoding the uptake hydrogenase on the activity of hydrogen production in the purple photosynthetic bacterium Rubrivivax gelatinosus IL144.
The Journal of general and applied microbiology, 2017Co-Authors: Takeshi Sato, Hidehiro Sakurai, Kazuhito Inoue, Kenji V. P. NagashimaAbstract:The efficiency of hydrogen gas production by nitrogenase in bacteria has been improved by the inhibition of antagonistic activity by the uptake hydrogenase. In this study, a mutant lacking the gene coding for the uptake hydrogenase was generated from the photosynthetic beta-proteobacterium Rubrivivax gelatinosus IL144 to explore new ways of hydrogen gas production driven by light energy. The mutant cells produced 25-30% higher amounts of molecular hydrogen than the wild-type cells under nitrogen-deficient conditions under light. Furthermore, by the addition of 5 mM glutamate, the photosynthetic growth rate was greatly enhanced, and the hydrogen gas production activity reached 41.1 (mmol/l) in the mutant.
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Effect of growth conditions on advantages of hup− strain for H2 photoproduction by Rubrivivax gelatinosus
International Journal of Hydrogen Energy, 2017Co-Authors: Tatyana V. Laurinavichene, Kenji V. P. Nagashima, Masaharu Kitashima, Takeshi Sato, Hidehiro Sakurai, Kazuhito Inoue, Anatoly A. TsygankovAbstract:H2 photoproduction by growing cultures of hup− mutant and parental strain RL2 of Rubrivivax gelatinosus was compared. We checked the influence of different substrates, presence of air and N2, culture shaking, inoculum concentrations. At low inoculum concentration, hup− strain demonstrated significant advantage over the parental strain in microaerobic conditions, while under N2–Ar atmosphere it was lower and vanished in anaerobic conditions (Ar only). This advantage was evident when using substrates with low degree of reduction (malate and succinate). Culture shaking under microaerobic conditions and in presence of N2 completely prevented H2 production by both strains. The high inoculum concentration inhibited H2 production under microaerobic conditions and in presence of N2, unlike to anaerobic conditions. With inoculum concentration increase, H2 production decreased not gradually but stepwise which means some metabolic shift. H2 production by hup− strain seems to be more tolerant to air traces than by parental strain.
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Photo-induced electron transfer in intact cells of Rubrivivax gelatinosus mutants deleted in the RC-bound tetraheme cytochrome: insight into evolution of photosynthetic electron transport.
Biochimica et biophysica acta, 2012Co-Authors: André Verméglio, Sakiko Nagashima, Jean Alric, Pascal Arnoux, Kenji V. P. NagashimaAbstract:Abstract Deletion of two of the major electron carriers, the reaction center-bound tetrahemic cytochrome and the HiPIP, involved in the light-induced cyclic electron transfer pathway of the purple photosynthetic bacterium, Rubrivivax gelatinosus, significantly impairs its anaerobic photosynthetic growth. Analysis on the light-induced absorption changes of the intact cells of the mutants shows, however, a relatively efficient photo-induced cyclic electron transfer. For the single mutant lacking the reaction center-bound cytochrome, we present evidence that the electron carrier connecting the reaction center and the cytochrome bc1 complex is the High Potential Iron–sulfur Protein. In the double mutant lacking both the reaction center-bound cytochrome and the High Potential Iron–sulfur Protein, this connection is achieved by the high potential cytochrome c8. Under anaerobic conditions, the halftime of re-reduction of the photo-oxidized primary donor by these electron donors is 3 to 4 times faster than the back reaction between P+ and the reduced primary quinone acceptor. This explains the photosynthetic growth of these two mutants. The results are discussed in terms of evolution of the type II RCs and their secondary electron donors.
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Cytochrome c4 Can Be Involved in the Photosynthetic Electron Transfer System in the Purple Bacterium Rubrivivax gelatinosus
Biochemistry, 2009Co-Authors: Makito Ohmine, Keizo Shimada, Katsumi Matsuura, André Verméglio, Jean Alric, Kenji V. P. NagashimaAbstract:Three periplasmic electron carriers, HiPIP and two cytochromes c8 with low- and high-midpoint potentials, are present in the purple photosynthetic bacterium Rubrivivax gelatinosus. Comparison of the growth rates of mutants lacking one, two, or all three electron carrier proteins showed that HiPIP is the main electron donor to the photochemical reaction center and that high-potential cytochrome c8 plays a subsidiary role in the electron donation in photosynthetically growing cells. However, the triple deletion mutant was still capable of photosynthetic growth, indicating that another electron donor could be present. A new soluble cytochrome c, which can reduce the photooxidized reaction center in vitro, was purified. Based on amino acid sequence comparisons to known cytochromes, this cytochrome was identified as a diheme cytochrome c of the family of cytochromes c4. The quadruple mutant lacking this cytochrome and three other electron carriers showed about three times slower growth than the triple mutant under photosynthetic growth conditions. In conclusion, cytochrome c4 can function as a physiological electron carrier in the photosynthetic electron transport chain in R. gelatinosus.
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Chimeric photosynthetic reaction center complex of purple bacteria composed of the core subunits of Rubrivivax gelatinosus and the cytochrome subunit of Blastochloris viridis.
The Journal of biological chemistry, 2002Co-Authors: Hideaki Maki, Keizo Shimada, Katsumi Matsuura, Kenji V. P. NagashimaAbstract:Abstract A gene coding for the photosynthetic reaction center-bound cytochrome subunit, pufC, ofBlastochloris viridis, which belongs to the α-purple bacteria, was introduced into Rubrivivax gelatinosus, which belongs to the β-purple bacteria. The cytochrome subunit of B. viridis was synthesized in the R. gelatinosus cells, in which the native pufC gene was knocked out, and formed a chimeric reaction center (RC) complex together with other subunits ofR. gelatinosus. The transformant was able to grow photosynthetically. Rapid photo-oxidization of the hemes in the cytochrome subunit was observed in the membrane of the transformant. The soluble electron carrier, cytochrome c 2, isolated from B. viridis was a good electron donor to the chimeric RC. The redox midpoint potentials and the redox difference spectra of four hemes in the cytochrome subunit of the chimeric RC were almost identical with those in the B. viridis RC. The cytochrome subunit of B. viridis seems to retain its structure and function in the R. gelatinosus cell. The chimeric RC and its mutagenesis system should be useful for further studies about the cytochrome subunit of B. viridis.
Pin Ching Maness - One of the best experts on this subject based on the ideXlab platform.
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Inactivation of the uptake hydrogenase in the purple non-sulfur photosynthetic bacterium Rubrivivax gelatinosus CBS enables a biological water–gas shift platform for H_2 production
Journal of Industrial Microbiology & Biotechnology, 2019Co-Authors: Carrie A. Eckert, Karen Wawrousek, Sharon Smolinski, Emily Freed, Pin Ching ManessAbstract:Biological H_2 production has potential to address energy security and environmental concerns if produced from renewable or waste sources. The purple non-sulfur photosynthetic bacterium Rubrivivax gelatinosus CBS produces H_2 while oxidizing CO, a component of synthesis gas (Syngas). CO-linked H_2 production is facilitated by an energy-converting hydrogenase (Ech), while a subsequent H_2 oxidation reaction is catalyzed by a membrane-bound hydrogenase (MBH). Both hydrogenases contain [NiFe] active sites requiring 6 maturation factors (HypA-F) for assembly, but it is unclear which of the two annotated sets of hyp genes are required for each in R. gelatinosus CBS. Herein, we report correlated expression of hyp1 genes with Ech genes and hyp2 expression with MBH genes. Moreover, we find that while Ech H_2 evolving activity is only delayed when hyp1 is deleted, hyp2 deletion completely disrupts MBH H_2 uptake, providing a platform for a biologically driven water–gas shift reaction to produce H_2 from CO.
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RESEARCH ARTICLE Genome Annotation Provides Insight into Carbon Monoxide and Hydrogen Metabolism in Rubrivivax gelatinosus
2016Co-Authors: Karen Wawrousek, Jin Chen, Scott Noble, Jonas Korlach, Carrie Eckert, Pin Ching ManessAbstract:We report here the sequencing and analysis of the genome of the purple non-sulfur photosynthetic bacterium Rubrivivax gelatinosus CBS. This microbe is a model for studies of its carboxydotrophic life style under anaerobic condition, based on its ability to utilize carbon monoxide (CO) as the sole carbon substrate and water as the electron acceptor, yielding CO2 and H2 as the end products. The CO-oxidation reaction is known to be catalyzed by two enzyme complexes, the CO dehydrogenase and hydrogenase. As expected, analysis of the genome of Rx. gelatinosus CBS reveals the presence of genes encoding both enzyme complexes. The CO-oxidation reaction is CO-inducible, which is consistent with the presence of two putative CO-sensing transcription factors in its genome. Genome analysis also reveals the presence of two additional hydrogenases, an uptake hydrogenase that liberates the electrons in H2 in support of cell growth, and a regulatory hydrogenase that senses H2 and relays the signal to a two-component system that ultimately controls synthesis of the uptake hydrogenase. The genome also contains two set
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Genome annotation provides insight into carbon monoxide and hydrogen metabolism in Rubrivivax gelatinosus.
PloS one, 2014Co-Authors: Karen Wawrousek, Jin Chen, Scott Noble, Jonas Korlach, Carrie Eckert, Pin Ching ManessAbstract:We report here the sequencing and analysis of the genome of the purple non-sulfur photosynthetic bacterium Rubrivivax gelatinosus CBS. This microbe is a model for studies of its carboxydotrophic life style under anaerobic condition, based on its ability to utilize carbon monoxide (CO) as the sole carbon substrate and water as the electron acceptor, yielding CO2 and H2 as the end products. The CO-oxidation reaction is known to be catalyzed by two enzyme complexes, the CO dehydrogenase and hydrogenase. As expected, analysis of the genome of Rx. gelatinosus CBS reveals the presence of genes encoding both enzyme complexes. The CO-oxidation reaction is CO-inducible, which is consistent with the presence of two putative CO-sensing transcription factors in its genome. Genome analysis also reveals the presence of two additional hydrogenases, an uptake hydrogenase that liberates the electrons in H2 in support of cell growth, and a regulatory hydrogenase that senses H2 and relays the signal to a two-component system that ultimately controls synthesis of the uptake hydrogenase. The genome also contains two sets of hydrogenase maturation genes which are known to assemble the catalytic metallocluster of the hydrogenase NiFe active site. Collectively, the genome sequence and analysis information reveals the blueprint of an intricate network of signal transduction pathways and its underlying regulation that enables Rx. gelatinosus CBS to thrive on CO or H2 in support of cell growth.
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An overview of the CO and H2 signal transduction pathways and metabolism in Rubrivivax gelatinosus CBS.
2014Co-Authors: Karen Wawrousek, Jin Chen, Scott Noble, Jonas Korlach, Carrie Eckert, Pin Ching ManessAbstract:An overview of the CO and H2 signal transduction pathways and metabolism in Rubrivivax gelatinosus CBS.
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Identity percentage of Rubrivivax gelatinosus CBS Hyp1, Hyp2 proteins and the Hyp proteins from Ralstonia eutropha H16, generated by NCBI P-BLAST search.
2014Co-Authors: Karen Wawrousek, Jin Chen, Scott Noble, Jonas Korlach, Carrie Eckert, Pin Ching ManessAbstract:Identity percentage of Rubrivivax gelatinosus CBS Hyp1, Hyp2 proteins and the Hyp proteins from Ralstonia eutropha H16, generated by NCBI P-BLAST search.
