@article{MitrovaTadjoungWaffoKaufmannetal.2018,
  author    = {Mitrova, Biljana and Tadjoung Waffo, Armel Franklin and Kaufmann, Paul and Iobbi-Nivol, Chantal and Leimk{\"u}hler, Silke and Wollenberger, Ulla},
  title     = {Trimethylamine N-Oxide Electrochemical Biosensor with a Chimeric Enzyme},
  series = {ChemElectroChem},
  volume    = {6},
  journal   = {ChemElectroChem},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {2196-0216},
  doi       = {10.1002/celc.201801422},
  pages     = {1732 -- 1737},
  year      = {2018},
  abstract  = {For the first time, an enzyme-based electrochemical biosensor system for determination of trimethylamine N-oxide (TMAO) is described. It employs an active chimeric variant of TorA in combination with an enzymatically deoxygenating system and a low-potential mediator for effective regeneration of the enzyme and cathodic current generation. TMAO reductase (TorA) is a molybdoenzyme found in marine and most enterobacteria that specifically catalyzes the reduction of TMAO to trimethylamine (TMA). The chimeric TorA, named TorA-FDH, corresponds to the apoform of TorA from Escherichia coli reconstituted with the molybdenum cofactor from formate dehydrogenase (FDH). Each enzyme, TorA and TorA-FDH, was immobilized on the surface of a carbon electrode and protected with a dialysis membrane. The biosensor operates at an applied potential of -0.8V [vs. Ag/AgCl (1M KCl)] under ambient air conditions thanks to an additional enzymatic O-2-scavenger system. A comparison between the two enzymatic sensors revealed a much higher sensitivity for the biosensor with immobilized TorA-FDH. This biosensor exhibits a sensitivity of 14.16nA/M TMAO in a useful measuring range of 2-110M with a detection limit of LOD=2.96nM (S/N=3), and was similar for TMAO in buffer and in spiked serum samples. With a response time of 16 +/- 2 s, the biosensor is stable over prolonged daily measurements (n=20). This electrochemical biosensor provides suitable applications in detecting TMAO levels in human serum.},
  language  = {en}
}
@article{OttoMareljaSchoofsetal.2018,
  author    = {Otto, Nils and Marelja, Zvonimir and Schoofs, Andreas and Kranenburg, Holger and Bittern, Jonas and Yildirim, Kerem and Berh, Dimitri and Bethke, Maria and Thomas, Silke and Rode, Sandra and Risse, Benjamin and Jiang, Xiaoyi and Pankratz, Michael and Leimk{\"u}hler, Silke and Kl{\"a}mbt, Christian},
  title     = {The sulfite oxidase Shopper controls neuronal activity by regulating glutamate homeostasis in Drosophila ensheathing glia},
  series = {Nature Communications},
  volume    = {9},
  journal   = {Nature Communications},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {2041-1723},
  doi       = {10.1038/s41467-018-05645-z},
  pages     = {12},
  year      = {2018},
  abstract  = {Specialized glial subtypes provide support to developing and functioning neural networks. Astrocytes modulate information processing by neurotransmitter recycling and release of neuromodulatory substances, whereas ensheathing glial cells have not been associated with neuromodulatory functions yet. To decipher a possible role of ensheathing glia in neuronal information processing, we screened for glial genes required in the Drosophila central nervous system for normal locomotor behavior. Shopper encodes a mitochondrial sulfite oxidase that is specifically required in ensheathing glia to regulate head bending and peristalsis. shopper mutants show elevated sulfite levels affecting the glutamate homeostasis which then act on neuronal network function. Interestingly, human patients lacking the Shopper homolog SUOX develop neurological symptoms, including seizures. Given an enhanced expression of SUOX by oligodendrocytes, our findings might indicate that in both invertebrates and vertebrates more than one glial cell type may be involved in modulating neuronal activity.},
  language  = {en}
}
@misc{OttoMareljaSchoofsetal.2018,
  author    = {Otto, Nils and Marelja, Zvonimir and Schoofs, Andreas and Kranenburg, Holger and Bittern, Jonas and Yildirim, Kerem and Berh, Dimitri and Bethke, Maria and Thomas, Silke and Rode, Sandra and Risse, Benjamin and Jiang, Xiaoyi and Pankratz, Michael and Leimk{\"u}hler, Silke and Kl{\"a}mbt, Christian},
  title     = {The sulfite oxidase Shopper controls neuronal activity by regulating glutamate homeostasis in Drosophila ensheathing glia},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  number    = {975},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-42620},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426205},
  pages     = {14},
  year      = {2018},
  abstract  = {Specialized glial subtypes provide support to developing and functioning neural networks. Astrocytes modulate information processing by neurotransmitter recycling and release of neuromodulatory substances, whereas ensheathing glial cells have not been associated with neuromodulatory functions yet. To decipher a possible role of ensheathing glia in neuronal information processing, we screened for glial genes required in the Drosophila central nervous system for normal locomotor behavior. Shopper encodes a mitochondrial sulfite oxidase that is specifically required in ensheathing glia to regulate head bending and peristalsis. shopper mutants show elevated sulfite levels affecting the glutamate homeostasis which then act on neuronal network function. Interestingly, human patients lacking the Shopper homolog SUOX develop neurological symptoms, including seizures. Given an enhanced expression of SUOX by oligodendrocytes, our findings might indicate that in both invertebrates and vertebrates more than one glial cell type may be involved in modulating neuronal activity.},
  language  = {en}
}
@misc{LemaireInfossiChaoucheetal.2018,
  author    = {Lemaire, Olivier N. and Infossi, Pascale and Chaouche, Amine Ali and Espinosa, Leon and Leimk{\"u}hler, Silke and Giudici-Orticoni, Marie-Th{\´e}r{\`e}se and M{\´e}jean, Vincent and Iobbi-Nivol, Chantal},
  title     = {Small membranous proteins of the TorE/NapE family, crutches for cognate respiratory systems in Proteobacteria},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {933},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-45920},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459208},
  pages     = {15},
  year      = {2018},
  abstract  = {In this report, we investigate small proteins involved in bacterial alternative respiratory systems that improve the enzymatic efficiency through better anchorage and multimerization of membrane components. Using the small protein TorE of the respiratory TMAO reductase system as a model, we discovered that TorE is part of a subfamily of small proteins that are present in proteobacteria in which they play a similar role for bacterial respiratory systems. We reveal by microscopy that, in Shewanella oneidensis MR1, alternative respiratory systems are evenly distributed in the membrane contrary to what has been described for Escherichia coli. Thus, the better efficiency of the respiratory systems observed in the presence of the small proteins is not due to a specific localization in the membrane, but rather to the formation of membranous complexes formed by TorE homologs with their c-type cytochrome partner protein. By an in vivo approach combining Clear Native electrophoresis and fluorescent translational fusions, we determined the 4: 4 stoichiometry of the complexes. In addition, mild solubilization of the cytochrome indicates that the presence of the small protein reinforces its anchoring to the membrane. Therefore, assembly of the complex induced by this small protein improves the efficiency of the respiratory system.},
  language  = {en}
}
@article{LemaireInfossiChaoucheetal.2018,
  author    = {Lemaire, Olivier N. and Infossi, Pascale and Chaouche, Amine Ali and Espinosa, Leon and Leimk{\"u}hler, Silke and Giudici-Orticoni, Marie-Therese and Mejean, Vincent and Iobbi-Nivol, Chantal},
  title     = {Small membranous proteins of the TorE/NapE family, crutches for cognate respiratory systems in Proteobacteria},
  series = {Scientific reports},
  volume    = {8},
  journal   = {Scientific reports},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/s41598-018-31851-2},
  pages     = {13},
  year      = {2018},
  abstract  = {In this report, we investigate small proteins involved in bacterial alternative respiratory systems that improve the enzymatic efficiency through better anchorage and multimerization of membrane components. Using the small protein TorE of the respiratory TMAO reductase system as a model, we discovered that TorE is part of a subfamily of small proteins that are present in proteobacteria in which they play a similar role for bacterial respiratory systems. We reveal by microscopy that, in Shewanella oneidensis MR1, alternative respiratory systems are evenly distributed in the membrane contrary to what has been described for Escherichia coli. Thus, the better efficiency of the respiratory systems observed in the presence of the small proteins is not due to a specific localization in the membrane, but rather to the formation of membranous complexes formed by TorE homologs with their c-type cytochrome partner protein. By an in vivo approach combining Clear Native electrophoresis and fluorescent translational fusions, we determined the 4: 4 stoichiometry of the complexes. In addition, mild solubilization of the cytochrome indicates that the presence of the small protein reinforces its anchoring to the membrane. Therefore, assembly of the complex induced by this small protein improves the efficiency of the respiratory system.},
  language  = {en}
}
@article{SchwanholdIobbiNivolLehmannetal.2018,
  author    = {Schwanhold, Nadine and Iobbi-Nivol, Chantal and Lehmann, Angelika and Leimk{\"u}hler, Silke},
  title     = {Same but different},
  series = {PLoS one},
  volume    = {13},
  journal   = {PLoS one},
  number    = {11},
  publisher = {PLoS},
  address   = {San Fransisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0201935},
  pages     = {24},
  year      = {2018},
  abstract  = {The maturation of bacterial molybdoenzymes is a complex process leading to the insertion of the bulky bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor into the apoenzyme. Most molybdoenzymes were shown to contain a specific chaperone for the insertion of the bis-MGD cofactor. Formate dehydrogenases (FDH) together with their molecular chaperone partner seem to display an exception to this specificity rule, since the chaperone FdhD has been proven to be involved in the maturation of all three FDH enzymes present in Escherichia colt. Multiple roles have been suggested for FdhD-like chaperones in the past, including the involvement in a sulfur transfer reaction from the L-cysteine desulfurase IscS to bis-MGD by the action of two cysteine residues present in a conserved CXXC motif of the chaperones. However, in this study we show by phylogenetic analyses that the CXXC motif is not conserved among FdhD-like chaperones. We compared in detail the FdhD-like homologues from Rhodobacter capsulatus and E. colt and show that their roles in the maturation of FDH enzymes from different subgroups can be exchanged. We reveal that bis-MGDbinding is a common characteristic of FdhD-like proteins and that the cofactor is bound with a sulfido-ligand at the molybdenum atom to the chaperone. Generally, we reveal that the cysteine residues in the motif CXXC of the chaperone are not essential for the production of active FDH enzymes.},
  language  = {en}
}
@article{KaufmannDuffusMitrovaetal.2018,
  author    = {Kaufmann, Hans Paul and Duffus, Benjamin R. and Mitrova, Biljana and Iobbi-Nivol, Chantal and Teutloff, Christian and Nimtz, Manfred and Jaensch, Lothar and Wollenberger, Ulla and Leimk{\"u}hler, Silke},
  title     = {Modulating the Molybdenum Coordination Sphere of Escherichia coli Trimethylamie N-Oxide Reductase},
  series = {Biochemistry},
  volume    = {57},
  journal   = {Biochemistry},
  number    = {7},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0006-2960},
  doi       = {10.1021/acs.biochem.7b01108},
  pages     = {1130 -- 1143},
  year      = {2018},
  abstract  = {The well-studied enterobacterium Escherichia coli present in the human gut can reduce trimethylamine N-oxide (TMAO) to trimethylamine during anaerobic respiration. The TMAO reductase TorA is a monomeric, bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor-containing enzyme that belongs to the dimethyl sulfoxide reductase family of molybdoenzymes. We report on a system for the in vitro reconstitution of TorA with molybdenum cofactors (Moco) from different sources. Higher TMAO reductase activities for TorA were obtained when using Moco sources containing a sulfido ligand at the molybdenum atom. For the first time, we were able to isolate functional bis-MGD from Rhodobacter capsulatus formate dehydrogenase (FDH), which remained intact in its isolated state and after insertion into apo-TorA yielded a highly active enzyme. Combined characterizations of the reconstituted TorA enzymes by electron paramagnetic resonance spectroscopy and direct electrochemistry emphasize that TorA activity can be modified by changes in the Mo coordination sphere. The combination of these results together with studies of amino acid exchanges at the active site led us to propose a novel model for binding of the substrate to the molybdenum atom of TorA.},
  language  = {en}
}
@article{BurschelDecovicNuberetal.2018,
  author    = {Burschel, Sabrina and Decovic, Doris Kreuzer and Nuber, Franziska and Stiller, Marie and Hofmann, Maud and Zupok, Arkadiusz and Siemiatkowska, Beata and Gorka, Michal Jakub and Leimk{\"u}hler, Silke and Friedrich, Thorsten},
  title     = {Iron-sulfur cluster carrier proteins involved in the assembly of Escherichia coli NADH},
  series = {Molecular microbiology},
  volume    = {111},
  journal   = {Molecular microbiology},
  number    = {1},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0950-382X},
  doi       = {10.1111/mmi.14137},
  pages     = {31 -- 45},
  year      = {2018},
  abstract  = {The NADH:ubiquinone oxidoreductase (respiratory complex I) is the main entry point for electrons into the Escherichia coli aerobic respiratory chain. With its sophisticated setup of 13 different subunits and 10 cofactors, it is anticipated that various chaperones are needed for its proper maturation. However, very little is known about the assembly of E. coli complex I, especially concerning the incorporation of the iron-sulfur clusters. To identify iron-sulfur cluster carrier proteins possibly involved in the process, we generated knockout strains of NfuA, BolA, YajL, Mrp, GrxD and IbaG that have been reported either to be involved in the maturation of mitochondrial complex I or to exert influence on the clusters of bacterial complex. We determined the NADH and succinate oxidase activities of membranes from the mutant strains to monitor the specificity of the individual mutations for complex I. The deletion of NfuA, BolA and Mrp led to a decreased stability and partially disturbed assembly of the complex as determined by sucrose gradient centrifugation and native PAGE. EPR spectroscopy of cytoplasmic membranes revealed that the BolA deletion results in the loss of the binuclear Fe/S cluster N1b.},
  language  = {en}
}
@article{MareljaLeimkuehlerMissirlis2018,
  author    = {Marelja, Zvonimir and Leimk{\"u}hler, Silke and Missirlis, Fanis},
  title     = {Iron sulfur and molybdenum cofactor enzymes regulate the drosophila life cycle by controlling cell metabolism},
  series = {Frontiers in physiology},
  volume    = {9},
  journal   = {Frontiers in physiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2018.00050},
  pages     = {31},
  year      = {2018},
  abstract  = {Iron sulfur (Fe-S) clusters and the molybdenum cofactor (Moco) are present at enzyme sites, where the active metal facilitates electron transfer. Such enzyme systems are soluble in the mitochondrial matrix, cytosol and nucleus, or embedded in the inner mitochondrial membrane, but virtually absent from the cell secretory pathway. They are of ancient evolutionary origin supporting respiration, DNA replication, transcription, translation, the biosynthesis of steroids, heme, catabolism of purines, hydroxylation of xenobiotics, and cellular sulfur metabolism. Here, Fe-S cluster and Moco biosynthesis in Drosophila melanogaster is reviewed and the multiple biochemical and physiological functions of known Fe-S and Moco enzymes are described. We show that RNA interference of Mocs3 disrupts Moco biosynthesis and the circadian clock. Fe-S-dependent mitochondrial respiration is discussed in the context of germ line and somatic development, stem cell differentiation and aging. The subcellular compartmentalization of the Fe-S and Moco assembly machinery components and their connections to iron sensing mechanisms and intermediary metabolism are emphasized. A biochemically active Fe-S core complex of heterologously expressed fly Nfs1, Isd11, IscU, and human frataxin is presented. Based on the recent demonstration that copper displaces the Fe-S cluster of yeast and human ferredoxin, an explanation for why high dietary copper leads to cytoplasmic iron deficiency in flies is proposed. Another proposal that exosomes contribute to the transport of xanthine dehydrogenase from peripheral tissues to the eye pigment cells is put forward, where the Vps16a subunit of the HOPS complex may have a specialized role in concentrating this enzyme within pigment granules. Finally, we formulate a hypothesis that (i) mitochondrial superoxide mobilizes iron from the Fe-S clusters in aconitase and succinate dehydrogenase; (ii) increased iron transiently displaces manganese on superoxide dismutase, which may function as a mitochondrial iron sensor since it is inactivated by iron; (iii) with the Krebs cycle thus disrupted, citrate is exported to the cytosol for fatty acid synthesis, while succinyl-CoA and the iron are used for heme biosynthesis; (iv) as iron is used for heme biosynthesis its concentration in the matrix drops allowing for manganese to reactivate superoxide dismutase and Fe-S cluster biosynthesis to reestablish the Krebs cycle.},
  language  = {en}
}
@misc{MareljaLeimkuehlerMissirlis2018,
  author    = {Marelja, Zvonimir and Leimk{\"u}hler, Silke and Missirlis, Fanis},
  title     = {Iron sulfur and molybdenum cofactor enzymes regulate the Drosophila life cycle by controlling cell metabolism},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {925},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-44567},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445670},
  pages     = {33},
  year      = {2018},
  abstract  = {Iron sulfur (Fe-S) clusters and the molybdenum cofactor (Moco) are present at enzyme sites, where the active metal facilitates electron transfer. Such enzyme systems are soluble in the mitochondrial matrix, cytosol and nucleus, or embedded in the inner mitochondrial membrane, but virtually absent from the cell secretory pathway. They are of ancient evolutionary origin supporting respiration, DNA replication, transcription, translation, the biosynthesis of steroids, heme, catabolism of purines, hydroxylation of xenobiotics, and cellular sulfur metabolism. Here, Fe-S cluster and Moco biosynthesis in Drosophila melanogaster is reviewed and the multiple biochemical and physiological functions of known Fe-S and Moco enzymes are described. We show that RNA interference of Mocs3 disrupts Moco biosynthesis and the circadian clock. Fe-S-dependent mitochondrial respiration is discussed in the context of germ line and somatic development, stem cell differentiation and aging. The subcellular compartmentalization of the Fe-S and Moco assembly machinery components and their connections to iron sensing mechanisms and intermediary metabolism are emphasized. A biochemically active Fe-S core complex of heterologously expressed fly Nfs1, Isd11, IscU, and human frataxin is presented. Based on the recent demonstration that copper displaces the Fe-S cluster of yeast and human ferredoxin, an explanation for why high dietary copper leads to cytoplasmic iron deficiency in flies is proposed. Another proposal that exosomes contribute to the transport of xanthine dehydrogenase from peripheral tissues to the eye pigment cells is put forward, where the Vps16a subunit of the HOPS complex may have a specialized role in concentrating this enzyme within pigment granules. Finally, we formulate a hypothesis that (i) mitochondrial superoxide mobilizes iron from the Fe-S clusters in aconitase and succinate dehydrogenase; (ii) increased iron transiently displaces manganese on superoxide dismutase, which may function as a mitochondrial iron sensor since it is inactivated by iron; (iii) with the Krebs cycle thus disrupted, citrate is exported to the cytosol for fatty acid synthesis, while succinyl-CoA and the iron are used for heme biosynthesis; (iv) as iron is used for heme biosynthesis its concentration in the matrix drops allowing for manganese to reactivate superoxide dismutase and Fe-S cluster biosynthesis to reestablish the Krebs cycle.},
  language  = {en}
}