Hydrogenase- and outer membrane c-type cytochrome-facilitated reduction of technetium(VII) by Shewanella oneidensis MR-1
| Autor: | James K. Fredrickson, Andrew E. Plymale, Chongxuan Liu, Alexander S. Beliaev, Samantha B. Reed, Alice Dohnalkova, Matthew J. Marshall, Daad A. Saffarini, Liang Shi, John M. Zachara, Margaret F. Romine, Cody J. Simonson, David W. Kennedy, Zheming Wang |
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| Rok vydání: | 2007 |
| Předmět: |
Iron-Sulfur Proteins
Shewanella Hydrogenase Cytochrome Stereochemistry Cytochrome c Group Electron donor Microbiology Electron Transport Electron transfer chemistry.chemical_compound Shewanella oneidensis Ecology Evolution Behavior and Systematics Sodium Pertechnetate Tc 99m biology Oxides Vitamin K 2 biology.organism_classification Electron transport chain Membrane Biochemistry chemistry biology.protein Bacterial outer membrane Oxidation-Reduction Bacterial Outer Membrane Proteins Hydrogen |
| Zdroj: | Environmental Microbiology. :070922000647001 |
| ISSN: | 1462-2920 1462-2912 |
| Popis: | Pertechnetate, (99)Tc(VII)O(4)(-), is a highly mobile radionuclide contaminant at US Department of Energy sites that can be enzymatically reduced by a range of anaerobic and facultatively anaerobic microorganisms, including Shewanella oneidensis MR-1, to poorly soluble Tc(IV)O(2(s)). In other microorganisms, Tc(VII)O(4)(-) reduction is generally considered to be catalysed by hydrogenase. Here, we provide evidence that although the NiFe hydrogenase of MR-1 was involved in the H(2)-driven reduction of Tc(VII)O(4)(-)[presumably through a direct coupling of H(2) oxidation and Tc(VII) reduction], the deletion of both hydrogenase genes did not completely eliminate the ability of MR-1 to reduce Tc(VII). With lactate as the electron donor, mutants lacking the outer membrane c-type cytochromes MtrC and OmcA or the proteins required for the maturation of c-type cytochromes were defective in reducing Tc(VII) to nanoparticulate TcO(2) x nH(2)O((s)) relative to MR-1 or a NiFe hydrogenase mutant. In addition, reduced MtrC and OmcA were oxidized by Tc(VII)O(4)(-), confirming the capacity for direct electron transfer from these OMCs to TcO(4)(-). c-Type cytochrome-catalysed Tc(VII) reduction could be a potentially important mechanism in environments where organic electron donor concentrations are sufficient to allow this reaction to dominate. |
| Databáze: | OpenAIRE |
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