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Jens Hartung - One of the best experts on this subject based on the ideXlab platform.
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Vanadate-dependent Bromoperoxidases from Ascophyllum nodosum in the synthesis of brominated phenols and pyrroles
Dalton Transactions, 2013Co-Authors: Diana Wischang, Madlen Radlow, Jens HartungAbstract:Bromoperoxidases from the brown alga Ascophyllum nodosum, abbreviated as VBrPO(AnI) and VBrPO(AnII), show 41% sequence homology and differ by a factor of two in the percentage of α-helical secondary structures. Protein monomers organize into homodimers for VBrPO(AnI) and hexamers for VBrPO(AnII). Bromoperoxidase II binds hydrogen peroxide and bromide by approximately one order of magnitude stronger than VBrPO(AnI). In oxidation catalysis, Bromoperoxidases I and II turn over hydrogen peroxide and bromide similarly fast, yielding in morpholine-4-ethanesulfonic acid (MES)-buffered aqueous tert-butanol (pH 6.2) molecular bromine as reagent for electrophilic hydrocarbon bromination. Alternative compounds, such as tribromide and hypobromous acid are not sufficiently electrophilic for being directly involved in carbon–bromine bond formation. A decrease in electrophilicity from bromine via hypobromous acid to tribromide correlates in a frontier molecular orbital (FMO) analysis with larger energy gaps between the π-type HOMO of, for example, an alkene and the σ*Br,X-type LUMO of the bromination reagent. By using this approach, the reactivity of substrates and selectivity for carbon–bromine bond formation in reactions mediated by vanadate-dependent Bromoperoxidases become predictable, as exemplified by the synthesis of bromopyrroles occurring naturally in marine sponges of the genera Agelas, Acanthella, and Axinella.
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Bromoperoxidases and functional enzyme mimics as catalysts for oxidative bromination—A sustainable synthetic approach
Coordination Chemistry Reviews, 2011Co-Authors: Diana Wischang, Oliver Brücher, Jens HartungAbstract:Abstract The discovery of enzymes that utilize hydrogen peroxide to oxidize bromide under physiological conditions provided a strong stimulus to the field of oxidative bromination. A synthetically useful enzyme, to catalyze the oxidation of bromide, for bromofunctionalization of donor-substituted arenes in solutions of hydrogen peroxide and sodium bromide, is a vanadate(V)-dependent Bromoperoxidase from the brown alga Ascophyllum nodosum . This enzyme operates in homogeneous solutions of buffered aqueous tert -butanol (pH 6.2), or, to simplify repetitive use, in a two-phase system after immobilization onto magnetic beads. Synthesis of cyclic bromohydrin ethers (tetrahydrofurans and tetrahydropyrans) and vicinal dibromides from unsaturated hydrocarbons, on the other hand, occurs more effectively in polar aprotic solvents. Under such conditions the more lipophilic tert -butyl hydroperoxide serves as oxidant, which is activated by oxovanadium(V) complexes (functional Bromoperoxidase mimics). Protons and bromide ions, which are consumed for in situ generation of bromine, are supplied in organic solution by fragmentation of 3-bromopropionic acids. The structure-reactivity data obtained from oxidations catalyzed by Bromoperoxidases and functional enzyme mimics pose a valuable guideline for predicting selectivity in biomimetic synthesis of organobromines from terpenes, acetogenins, and pyrrole alkaloids.
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Bromoperoxidases and functional enzyme mimics as catalysts for oxidative bromination a sustainable synthetic approach
Coordination Chemistry Reviews, 2011Co-Authors: Diana Wischang, Oliver Brücher, Jens HartungAbstract:Abstract The discovery of enzymes that utilize hydrogen peroxide to oxidize bromide under physiological conditions provided a strong stimulus to the field of oxidative bromination. A synthetically useful enzyme, to catalyze the oxidation of bromide, for bromofunctionalization of donor-substituted arenes in solutions of hydrogen peroxide and sodium bromide, is a vanadate(V)-dependent Bromoperoxidase from the brown alga Ascophyllum nodosum . This enzyme operates in homogeneous solutions of buffered aqueous tert -butanol (pH 6.2), or, to simplify repetitive use, in a two-phase system after immobilization onto magnetic beads. Synthesis of cyclic bromohydrin ethers (tetrahydrofurans and tetrahydropyrans) and vicinal dibromides from unsaturated hydrocarbons, on the other hand, occurs more effectively in polar aprotic solvents. Under such conditions the more lipophilic tert -butyl hydroperoxide serves as oxidant, which is activated by oxovanadium(V) complexes (functional Bromoperoxidase mimics). Protons and bromide ions, which are consumed for in situ generation of bromine, are supplied in organic solution by fragmentation of 3-bromopropionic acids. The structure-reactivity data obtained from oxidations catalyzed by Bromoperoxidases and functional enzyme mimics pose a valuable guideline for predicting selectivity in biomimetic synthesis of organobromines from terpenes, acetogenins, and pyrrole alkaloids.
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vanadate v dependent Bromoperoxidase immobilized on magnetic beads as reusable catalyst for oxidative bromination
Green Chemistry, 2011Co-Authors: Diana Wischang, Tobias Stumpf, Jens Hartung, Roland Ulber, Thomas Hahn, Claudia FechertrostAbstract:Vanadate(V)-dependent Bromoperoxidase I (Ascophyllum nodosum) was immobilized on magnetic micrometre-sized particles in quantitative yields, with up to 40% retention of initial Bromoperoxidase (BPO) activity. The immobilized enzyme was stable with a half-life time of about 160 days. It served as reusable catalyst for bromide oxidation with H2O2 in up to 14 consecutive experiments. Reactivity that resulted from enzymatic bromide oxidation was applicable for methyl pyrrole-2-carboxylate conversion into derivatives of naturally occurring compounds (e.g. from Agelas oroides) with product selectivity of up to 75%.
Ron Wever - One of the best experts on this subject based on the ideXlab platform.
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laboratory evolved vanadium chloroperoxidase exhibits 100 fold higher halogenating activity at alkaline ph catalytic effects from first and second coordination sphere mutations
Journal of Biological Chemistry, 2006Co-Authors: Zulfiqar Hasan, Rokus Renirie, Richard Kerkman, Harald J Ruijssenaars, Aloysius F Hartog, Ron WeverAbstract:Directed evolution was performed on vanadium chloroperoxidase from the fungus Curvularia inaequalis to increase its brominating activity at a mildly alkaline pH for industrial and synthetic applications and to further understand its mechanism. After successful expression of the enzyme in Escherichia coli, two rounds of screening and selection, saturation mutagenesis of a "hot spot," and rational recombination, a triple mutant (P395D/L241V/T343A) was obtained that showed a 100-fold increase in activity at pH 8 (k(cat) = 100 s(-1)). The increased K(m) values for Br(-) (3.1 mm) and H(2)O(2) (16 microm) are smaller than those found for vanadium Bromoperoxidases that are reasonably active at this pH. In addition the brominating activity at pH 5 was increased by a factor of 6 (k(cat) = 575 s(-1)), and the chlorinating activity at pH 5 was increased by a factor of 2 (k(cat) = 36 s(-1)), yielding the "best" vanadium haloperoxidase known thus far. The mutations are in the first and second coordination sphere of the vanadate cofactor, and the catalytic effects suggest that fine tuning of residues Lys-353 and Phe-397, along with addition of negative charge or removal of positive charge near one of the vanadate oxygens, is very important. Lys-353 and Phe-397 were previously assigned to be essential in peroxide activation and halide binding. Analysis of the catalytic parameters of the mutant vanadium Bromoperoxidase from the seaweed Ascophyllum nodosum also adds fuel to the discussion regarding factors governing the halide specificity of vanadium haloperoxidases. This study presents the first example of directed evolution of a vanadium enzyme.
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expression of the vanadium dependent Bromoperoxidase gene from a marine macro alga corallina pilulifera in saccharomyces cerevisiae and characterization of the recombinant enzyme
Phytochemistry, 2002Co-Authors: Takashi Ohshiro, Ron Wever, Toshiaki Aibara, Wieger Hemrika, Yoshikazu IzumiAbstract:Abstract The vanadium-dependent Bromoperoxidase from the marine macro-alga Corallina pilulifera was heterologously expressed in Saccharomyces cerevisiae . The enzyme was purified and crystals in “tear drop” form were obtained. The catalytic properties of the recombinant enzyme were studied and compared with those of the native enzyme purified from C. pilulifera . Differences in thermal stability and chloroperoxidase activity were observed. The recombinant enzyme retained full activity after preincubation at 65 °C for 20 min, but the native enzyme was completely inactivated under the same conditions. The chlorinating activity of the native enzyme was more than ten times higher than that of the recombinant enzyme. Other properties, such as K m values for KBr and H 2 O 2 , and optimal temperature and pH, were similar for each source of C. pilulifera Bromoperoxidase.
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Bromoperoxidase activity of vanadate substituted acid phosphatases from shigella flexneri and salmonella enterica ser typhimurium
FEBS Journal, 2002Co-Authors: Naoko Tanaka, Qianning Liao, Valerie Dumay, Alex J. Lange, Ron WeverAbstract:Vanadium haloperoxidases and the bacterial class A nonspecific acid phosphatases have a conserved active site. It is shown that vanadate-substituted recombinant acid phosphatase from Shigella flexneri (PhoN-Sf) and Salmonella enterica ser. typhimurium (PhoN-Se) in the presence of H2O2 are able to oxidize bromide to hypobromous acid. Vanadate is essential for this activity. The kinetic parameters for the artificial Bromoperoxidases have been determined. The Km value for H2O2 is about the same as that for the vanadium Bromoperoxidases from the seaweed Ascophyllum nodosum. However, the Km value for Br– is about 10–20 times higher, and the turnover values of about 3.4 min−1 and 33 min−1 for PhoN-Sf and PhoN-Se, respectively, are much slower, than those of the native Bromoperoxidase. Thus, despite the striking similarity in the active-site structures of the vanadium haloperoxidases and the acid phophatase, the turnover frequency is low, and clearly the active site of acid phosphatases is not optimized for haloperoxidase activity. Like the native vanadium Bromoperoxidase, the vanadate-substituted PhoN-Sf and PhoN-Se catalyse the enantioselective sulfoxidation of thioanisole.
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Expression of the vanadium-dependent Bromoperoxidase gene from a marine macro-alga Corallina pilulifera in Saccharomyces cerevisiae and characterization of the recombinant enzyme.
Phytochemistry, 2002Co-Authors: Takashi Ohshiro, Ron Wever, Toshiaki Aibara, Wieger Hemrika, Yoshikazu IzumiAbstract:The vanadium-dependent Bromoperoxidase from the marine macro-alga Corallina pilulifera was heterologously expressed in Saccharomyces cerevisiae. The enzyme was purified and crystals in "tear drop" form were obtained. The catalytic properties of the recombinant enzyme were studied and compared with those of the native enzyme purified from C. pilulifera. Differences in thermal stability and chloroperoxidase activity were observed. The recombinant enzyme retained full activity after preincubation at 65 degrees C for 20 min, but the native enzyme was completely inactivated under the same conditions. The chlorinating activity of the native enzyme was more than ten times higher than that of the recombinant enzyme. Other properties, such as K(m) values for KBr and H(2)O(2), and optimal temperature and pH, were similar for each source of C. pilulifera Bromoperoxidase.
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sulfoxidation mechanism of vanadium Bromoperoxidase from ascophyllum nodosum evidence for direct oxygen transfer catalysis
FEBS Journal, 2001Co-Authors: Hilda Ten B Brink, Hans E Schoemaker, Ron WeverAbstract:We have previously shown that vanadium Bromoperoxidase from Ascophyllum nodosum mediates production of the (R)-enantiomer of methyl phenyl sulfoxide with 91% enantiomeric excess. Investigation of the intrinsic selectivity of vanadium Bromoperoxidase reveals that the enzyme catalyzes the sulfoxidation of methyl phenyl sulfide in a purely enantioselective manner. The Km of the enzyme for methyl phenyl sulfide was determined to be ≈ 3.5 mm in the presence of 25% methanol or tert-butanol. The selectivity of the sulfoxidation of methyl phenyl sulfide is optimal in the temperature range 25–30 °C and can be further optimized by increasing the enzyme concentration, yielding selectivities with up to 96% enantiomeric excess. Furthermore, we established for the first time that vanadium Bromoperoxidase is functional at temperatures up to 70 °C. A detailed investigation of the sulfoxidation activity of this enzyme using 18O-labeled hydrogen peroxide shows that vanadium Bromoperoxidase mediates the direct transfer of the peroxide oxygen to the sulfide. A schematic model of the vanadium haloperoxidase sulfoxidation mechanism is presented.
Diana Wischang - One of the best experts on this subject based on the ideXlab platform.
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Vanadate-dependent Bromoperoxidases from Ascophyllum nodosum in the synthesis of brominated phenols and pyrroles
Dalton Transactions, 2013Co-Authors: Diana Wischang, Madlen Radlow, Jens HartungAbstract:Bromoperoxidases from the brown alga Ascophyllum nodosum, abbreviated as VBrPO(AnI) and VBrPO(AnII), show 41% sequence homology and differ by a factor of two in the percentage of α-helical secondary structures. Protein monomers organize into homodimers for VBrPO(AnI) and hexamers for VBrPO(AnII). Bromoperoxidase II binds hydrogen peroxide and bromide by approximately one order of magnitude stronger than VBrPO(AnI). In oxidation catalysis, Bromoperoxidases I and II turn over hydrogen peroxide and bromide similarly fast, yielding in morpholine-4-ethanesulfonic acid (MES)-buffered aqueous tert-butanol (pH 6.2) molecular bromine as reagent for electrophilic hydrocarbon bromination. Alternative compounds, such as tribromide and hypobromous acid are not sufficiently electrophilic for being directly involved in carbon–bromine bond formation. A decrease in electrophilicity from bromine via hypobromous acid to tribromide correlates in a frontier molecular orbital (FMO) analysis with larger energy gaps between the π-type HOMO of, for example, an alkene and the σ*Br,X-type LUMO of the bromination reagent. By using this approach, the reactivity of substrates and selectivity for carbon–bromine bond formation in reactions mediated by vanadate-dependent Bromoperoxidases become predictable, as exemplified by the synthesis of bromopyrroles occurring naturally in marine sponges of the genera Agelas, Acanthella, and Axinella.
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molecular cloning structure and reactivity of the second Bromoperoxidase from ascophyllum nodosum
Bioorganic Chemistry, 2012Co-Authors: Diana Wischang, Madlen Radlow, Heiko Schulz, Lutz Viehweger, Carsten Kegler, Jennifer Herrmann, Rolf Müller, Hans Vilter, Matthias Altmeyer, Fanny GaillardAbstract:Abstract The sequence of Bromoperoxidase II from the brown alga Ascophyllum nodosum was determined from a full length cloned cDNA, obtained from a tandem mass spectrometry RT-PCR-approach. The clone encodes a protein composed of 641 amino-acids, which provides a mature 67.4 kDa-Bromoperoxidase II-protein (620 amino-acids). Based on 43% sequence homology with the previously characterized Bromoperoxidase I from A. nodosum , a tertiary structure was modeled for the Bromoperoxidase II. The structural model was refined on the basis of results from gel filtration and vanadate-binding studies, showing that the Bromoperoxidase II is a hexameric metalloprotein, which binds 0.5 equivalents of vanadate as cofactor per 67.4 kDa-subunit, for catalyzing oxidation of bromide by hydrogen peroxide in a bi-bi-ping-pong mechanism ( k cat = 153 s −1 , 22 °C, pH 5.9). Bromide thereby is converted into a bromoelectrophile of reactivity similar to molecular bromine, based on competition kinetic data on phenol bromination and correlation analysis. Reactivity provided by the Bromoperoxidase II mimics biosynthesis of methyl 4-bromopyrrole-2-carboxylate, a natural product isolated from the marine sponge Axinella tenuidigitata .
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Bromoperoxidases and functional enzyme mimics as catalysts for oxidative bromination—A sustainable synthetic approach
Coordination Chemistry Reviews, 2011Co-Authors: Diana Wischang, Oliver Brücher, Jens HartungAbstract:Abstract The discovery of enzymes that utilize hydrogen peroxide to oxidize bromide under physiological conditions provided a strong stimulus to the field of oxidative bromination. A synthetically useful enzyme, to catalyze the oxidation of bromide, for bromofunctionalization of donor-substituted arenes in solutions of hydrogen peroxide and sodium bromide, is a vanadate(V)-dependent Bromoperoxidase from the brown alga Ascophyllum nodosum . This enzyme operates in homogeneous solutions of buffered aqueous tert -butanol (pH 6.2), or, to simplify repetitive use, in a two-phase system after immobilization onto magnetic beads. Synthesis of cyclic bromohydrin ethers (tetrahydrofurans and tetrahydropyrans) and vicinal dibromides from unsaturated hydrocarbons, on the other hand, occurs more effectively in polar aprotic solvents. Under such conditions the more lipophilic tert -butyl hydroperoxide serves as oxidant, which is activated by oxovanadium(V) complexes (functional Bromoperoxidase mimics). Protons and bromide ions, which are consumed for in situ generation of bromine, are supplied in organic solution by fragmentation of 3-bromopropionic acids. The structure-reactivity data obtained from oxidations catalyzed by Bromoperoxidases and functional enzyme mimics pose a valuable guideline for predicting selectivity in biomimetic synthesis of organobromines from terpenes, acetogenins, and pyrrole alkaloids.
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Bromoperoxidases and functional enzyme mimics as catalysts for oxidative bromination a sustainable synthetic approach
Coordination Chemistry Reviews, 2011Co-Authors: Diana Wischang, Oliver Brücher, Jens HartungAbstract:Abstract The discovery of enzymes that utilize hydrogen peroxide to oxidize bromide under physiological conditions provided a strong stimulus to the field of oxidative bromination. A synthetically useful enzyme, to catalyze the oxidation of bromide, for bromofunctionalization of donor-substituted arenes in solutions of hydrogen peroxide and sodium bromide, is a vanadate(V)-dependent Bromoperoxidase from the brown alga Ascophyllum nodosum . This enzyme operates in homogeneous solutions of buffered aqueous tert -butanol (pH 6.2), or, to simplify repetitive use, in a two-phase system after immobilization onto magnetic beads. Synthesis of cyclic bromohydrin ethers (tetrahydrofurans and tetrahydropyrans) and vicinal dibromides from unsaturated hydrocarbons, on the other hand, occurs more effectively in polar aprotic solvents. Under such conditions the more lipophilic tert -butyl hydroperoxide serves as oxidant, which is activated by oxovanadium(V) complexes (functional Bromoperoxidase mimics). Protons and bromide ions, which are consumed for in situ generation of bromine, are supplied in organic solution by fragmentation of 3-bromopropionic acids. The structure-reactivity data obtained from oxidations catalyzed by Bromoperoxidases and functional enzyme mimics pose a valuable guideline for predicting selectivity in biomimetic synthesis of organobromines from terpenes, acetogenins, and pyrrole alkaloids.
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vanadate v dependent Bromoperoxidase immobilized on magnetic beads as reusable catalyst for oxidative bromination
Green Chemistry, 2011Co-Authors: Diana Wischang, Tobias Stumpf, Jens Hartung, Roland Ulber, Thomas Hahn, Claudia FechertrostAbstract:Vanadate(V)-dependent Bromoperoxidase I (Ascophyllum nodosum) was immobilized on magnetic micrometre-sized particles in quantitative yields, with up to 40% retention of initial Bromoperoxidase (BPO) activity. The immobilized enzyme was stable with a half-life time of about 160 days. It served as reusable catalyst for bromide oxidation with H2O2 in up to 14 consecutive experiments. Reactivity that resulted from enzymatic bromide oxidation was applicable for methyl pyrrole-2-carboxylate conversion into derivatives of naturally occurring compounds (e.g. from Agelas oroides) with product selectivity of up to 75%.
B Brahamsha - One of the best experts on this subject based on the ideXlab platform.
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characterization of a functional vanadium dependent Bromoperoxidase in the marine cyanobacterium synechococcus sp cc9311 1
Journal of Phycology, 2011Co-Authors: Todd L Johnson, Brian Palenik, B BrahamshaAbstract:: Vanadium-dependent Bromoperoxidases (VBPOs) are characterized by the ability to oxidize halides using hydrogen peroxide. These enzymes are well-studied in eukaryotic macroalgae and are known to produce a variety of brominated secondary metabolites. Though genes have been annotated as VBPO in multiple prokaryotic genomes, they remain uncharacterized. The genome of the coastal marine cyanobacterium Synechococcus sp. CC9311 encodes a predicted VBPO (YP_731869.1, sync_2681), and in this study, we show that protein extracts from axenic cultures of Synechococcus possess Bromoperoxidase activity, oxidizing bromide and iodide, but not chloride. In-gel activity assays of Synechococcus proteins separated using PAGE reveal a single band having VBPO activity. When sequenced via liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS), peptides from the band aligned to the VBPO sequence predicted by the open reading frame (ORF) sync_2681. We show that a VBPO gene is present in a closely related strain, Synechococcus sp. WH8020, but not other clade I Synechococcus strains, consistent with recent horizontal transfer of the gene into Synechococcus. Diverse cyanobacterial-like VBPO genes were detected in a pelagic environment off the California coast using PCR. Investigation of functional VBPOs in unicellular cyanobacteria may lead to discovery of novel halogenated molecules and a better understanding of these organisms' chemical ecology and physiology.
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characterization of a functional vanadium dependent Bromoperoxidase in the marine cyanobacterium synechococcus sp cc9311 1
Journal of Phycology, 2011Co-Authors: Todd L Johnson, Brian Palenik, B BrahamshaAbstract:: Vanadium-dependent Bromoperoxidases (VBPOs) are characterized by the ability to oxidize halides using hydrogen peroxide. These enzymes are well-studied in eukaryotic macroalgae and are known to produce a variety of brominated secondary metabolites. Though genes have been annotated as VBPO in multiple prokaryotic genomes, they remain uncharacterized. The genome of the coastal marine cyanobacterium Synechococcus sp. CC9311 encodes a predicted VBPO (YP_731869.1, sync_2681), and in this study, we show that protein extracts from axenic cultures of Synechococcus possess Bromoperoxidase activity, oxidizing bromide and iodide, but not chloride. In-gel activity assays of Synechococcus proteins separated using PAGE reveal a single band having VBPO activity. When sequenced via liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS), peptides from the band aligned to the VBPO sequence predicted by the open reading frame (ORF) sync_2681. We show that a VBPO gene is present in a closely related strain, Synechococcus sp. WH8020, but not other clade I Synechococcus strains, consistent with recent horizontal transfer of the gene into Synechococcus. Diverse cyanobacterial-like VBPO genes were detected in a pelagic environment off the California coast using PCR. Investigation of functional VBPOs in unicellular cyanobacteria may lead to discovery of novel halogenated molecules and a better understanding of these organisms' chemical ecology and physiology.
Yoshikazu Izumi - One of the best experts on this subject based on the ideXlab platform.
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expression of the vanadium dependent Bromoperoxidase gene from a marine macro alga corallina pilulifera in saccharomyces cerevisiae and characterization of the recombinant enzyme
Phytochemistry, 2002Co-Authors: Takashi Ohshiro, Ron Wever, Toshiaki Aibara, Wieger Hemrika, Yoshikazu IzumiAbstract:Abstract The vanadium-dependent Bromoperoxidase from the marine macro-alga Corallina pilulifera was heterologously expressed in Saccharomyces cerevisiae . The enzyme was purified and crystals in “tear drop” form were obtained. The catalytic properties of the recombinant enzyme were studied and compared with those of the native enzyme purified from C. pilulifera . Differences in thermal stability and chloroperoxidase activity were observed. The recombinant enzyme retained full activity after preincubation at 65 °C for 20 min, but the native enzyme was completely inactivated under the same conditions. The chlorinating activity of the native enzyme was more than ten times higher than that of the recombinant enzyme. Other properties, such as K m values for KBr and H 2 O 2 , and optimal temperature and pH, were similar for each source of C. pilulifera Bromoperoxidase.
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Expression of the vanadium-dependent Bromoperoxidase gene from a marine macro-alga Corallina pilulifera in Saccharomyces cerevisiae and characterization of the recombinant enzyme.
Phytochemistry, 2002Co-Authors: Takashi Ohshiro, Ron Wever, Toshiaki Aibara, Wieger Hemrika, Yoshikazu IzumiAbstract:The vanadium-dependent Bromoperoxidase from the marine macro-alga Corallina pilulifera was heterologously expressed in Saccharomyces cerevisiae. The enzyme was purified and crystals in "tear drop" form were obtained. The catalytic properties of the recombinant enzyme were studied and compared with those of the native enzyme purified from C. pilulifera. Differences in thermal stability and chloroperoxidase activity were observed. The recombinant enzyme retained full activity after preincubation at 65 degrees C for 20 min, but the native enzyme was completely inactivated under the same conditions. The chlorinating activity of the native enzyme was more than ten times higher than that of the recombinant enzyme. Other properties, such as K(m) values for KBr and H(2)O(2), and optimal temperature and pH, were similar for each source of C. pilulifera Bromoperoxidase.
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crystal structure of dodecameric vanadium dependent Bromoperoxidase from the red algae corallina officinalis
Journal of Molecular Biology, 2000Co-Authors: Michail N. Isupov, Yoshikazu Izumi, Amanda A. Brindley, Andrew R Dalby, Garib N. Murshudov, Tadashi Tanabe, Jennifer A. LittlechildAbstract:Abstract The three-dimensional structure of the vanadium Bromoperoxidase protein from the marine red macroalgae Corallina officinalis has been determined by single isomorphous replacement at 2.3 A resolution. The enzyme subunit is made up of 595 amino acid residues folded into a single α+β domain. There are 12 Bromoperoxidase subunits, arranged with 23-point group symmetry. A cavity is formed by the N terminus of each subunit in the centre of the dodecamer. The subunit fold and dimer organisation of the Cor. officinalis vanadium Bromoperoxidase are similar to those of the dimeric enzyme from the brown algae Ascophyllum nodosum , with which it shares 33 % sequence identity. The different oligomeric state of the two algal enzymes seems to reflect separate mechanisms of adaptation to harsh environmental conditions and/or to chemically active substrates and products. The residues involved in the vanadate binding are conserved between the two algal Bromoperoxidases and the vanadium chloroperoxidase from the fungus Curvularia inaequalis . However, most of the other residues forming the active-site cavity are different in the three enzymes, which reflects differences in the substrate specificity and stereoselectivity of the reaction. A dimer of the Cor. officinalis enzyme partially superimposes with the two-domain monomer of the fungal enzyme.
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occurrence of Bromoperoxidase in the marine green macro alga ulvella lens and emission of volatile brominated methane by the enzyme
Phytochemistry, 1999Co-Authors: Takashi Ohshiro, Yoshinori Takahashi, Satoru Nakano, Minoru Suzuki, Yoshikazu IzumiAbstract:Abstract Bromoperoxidase activity was detected in the marine green macro-alga, Ulvella lens, which is used to induce the larval metamorphosis of sea urchin in aquaculture in Japan. The enzyme activity was enhanced 8.5- and 2.2-fold by the addition of cobalt and vanadium ions to the reaction mixture, respectively. The volatile halogenated compounds dibromomethane and tribromomethane were formed in the reaction mixture when the enzyme was incubated with oxaloacetate, hydrogen peroxide and potassium bromide. These results suggest that dibromomethane, which was reported to be released by U. lens and play an important role as the inducer of larval settlement and metamorphosis, is produced by Bromoperoxidase in the alga.
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Enantioselective Sulfoxidation Catalyzed by Vanadium Haloperoxidases.
Inorganic chemistry, 1998Co-Authors: Hilda B. Ten Brink, Yoshikazu Izumi, Hans E Schoemaker, Wieger Hemrika, Antonin Tuynman, Henk L. Dekker, Takashi Oshiro, Ron WeverAbstract:Vanadium haloperoxidases catalyze the oxidation of halides by hydrogen peroxide to produce hypohalous acid. We demonstrate that these enzymes also slowly mediate the enantioselective oxidation of organic sulfides (methyl phenyl sulfide, methyl p-tolyl sulfide, and 1-methoxy-4 (methylthio)benzene) to the corresponding sulfoxides (turnover frequency 1 min(-)(1)). The vanadium Bromoperoxidase from the brown seaweed Ascophyllum nodosum converts methyl phenyl sulfide to the (R)-enantiomer of the sulfoxide (55% yield and 85% enantiomeric excess (ee)). At low peroxide concentrations a selectivity of 91% can be attained. The enzyme catalyzes the selective sulfoxidation reaction over a broad pH range with an optimum around pH 5-6 and remains completely functional during the reaction. When the vanadium Bromoperoxidase from the red seaweed Corallina pilulifera is used the (S)-enantiomer (18% yield and 55% ee) is formed. In contrast, the vanadium chloroperoxidase from the fungus Curvularia inaequalis catalyzes the production of a racemic mixture (54% yield), which seems to be an intrinsic characteristic of this enzyme.
