Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.17 (PCE)
 1,301 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tetrachloroethene (PCE) respiration was studied in the tetrachloroethene-utilizing anaerobe, Dehalospirillum multivorans, with respect to localization of the catabolic enzymes, the electron carriers potentially involved in electron transport, and the response to ionophores and specific inhibitors. Hydrogenase and formate dehydrogenase were recovered in the periplasmic cell fraction and were membrane-associated. Electron-accepting tetrachloroethene dehalogenase was found in the cytoplasmic fraction. In the PCE dehalogenase assay, only artificial electron donors with a standard redox potential of D. multivorans (Eo' = -445 mV) could serve as electron donor for PCE reduction. However, the reaction rate with ferredoxin was only 1% of that with methyl viologen, whereas the pyruvate-ferredoxin oxidoreductase exhibited almost the same reaction rates with methyl viologen and ferredoxin as electron acceptors for pyruvate oxidation. Reduced menadione (2-methyl-1, 4-naphthoquinone) did not serve as electron donor in the PCE dehalogenase reaction. 2-Heptyl-4-hydroxyquinoline-N-oxide (HOQNO) had no significant effect on PCE dechlorination in cell suspensions and in crude extracts. Whole cells catalyzed the reductive dechlorination of PCE with H2 or formate as electron donors. The dechlorination in cell suspensions rather than in cell extracts was inhibited by the ionophores carbonylcyanide-p-(trifluoromethoxy)phenylhydrazone (FCCP) and tetrachlorosalicylanilide (TCS), indicating that a membrane potential and/or a pH gradient may be required for the reaction in vivo.
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PMID:Studies on tetrachloroethene respiration in Dehalospirillum multivorans. 908 14

Desulfitobacterium hafniense Y51 is a dechlorinating bacterium that encodes an unusually large set of O-demethylase paralogs and specialized respiratory systems including specialized electron donors and acceptors. To use this organism in bioremediation of tetrachloroethene (PCE) or trichloroethene (TCE) pollution, expression patterns of its 5,060 genes were determined under different conditions using 60-mer probes in DNA microarrays. PCE, TCE, fumarate, nitrate, and dimethyl sulfoxide (DMSO) respiration all sustain the growth of strain Y51. Global transcriptome analyses were thus performed using various electron donor and acceptor couples (respectively, pyruvate and either fumarate, TCE, nitrate, or DMSO, and vanillate/fumarate). When TCE is used as terminal electron acceptor, resulting in its detoxification, a series of electron carriers comprising a cytochrome bd-type quinol oxidase (DSY4055-4056), a ferredoxin (DSY1451), and four Fe-S proteins (DSY1626, DSY1629, DSY0733, DSY3309) are upregulated, suggesting that the products of these genes are involved in PCE oxidoreduction. Interestingly, the PCE dehalogenase cluster (pceABCT) is constitutively expressed in the media tested, with pceT being upregulated and pceC downregulated in pyruvate/TCE-containing medium. In addition, another dehalogenation enzyme (DSY1155 coding for a putative chlorophenol reductive dehalogenase), is induced 225-fold in that medium, despite not being involved in PCE respiration. Remarkably since the reducing equivalents formed during pyruvate conversion to acetyl-CoA are channeled to electron acceptors including halogenated compounds, pyruvate induces expression of a pyruvate:ferredoxin oxidoreductase. This study paves the way to understanding the physiology of D. hafniense, optimizing this microbe as a bioremediation agent, and designing bioarray sensors to monitor the presence of dechlorinating organisms in the environment.
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PMID:Global transcriptome analysis of the tetrachloroethene-dechlorinating bacterium Desulfitobacterium hafniense Y51 in the presence of various electron donors and terminal electron acceptors. 2186 Nov 58

Organohalide respiration is an environmentally important but poorly characterized type of anaerobic respiration. We compared the global proteome of the versatile organohalide-respiring Epsilonproteobacterium Sulfurospirillum multivorans grown with different electron acceptors (fumarate, nitrate, or tetrachloroethene [PCE]). The most significant differences in protein abundance were found for gene products of the organohalide respiration region. This genomic region encodes the corrinoid and FeS cluster containing PCE reductive dehalogenase PceA and other proteins putatively involved in PCE metabolism such as those involved in corrinoid biosynthesis. The latter gene products as well as PceA and a putative quinol dehydrogenase were almost exclusively detected in cells grown with PCE. This finding suggests an electron flow from the electron donor such as formate or pyruvate via the quinone pool and a quinol dehydrogenase to PceA and the terminal electron acceptor PCE. Two putative accessory proteins, an IscU-like protein and a peroxidase-like protein, were detected with PCE only and might be involved in PceA maturation. The proteome of cells grown with pyruvate instead of formate as electron donor indicates a route of electrons from reduced ferredoxin via an Epsilonproteobacterial complex I and the quinone pool to PCE.
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PMID:Proteomics of the organohalide-respiring Epsilonproteobacterium Sulfurospirillum multivorans adapted to tetrachloroethene and other energy substrates. 2638 27