Certain methanogens deteriorate steel surfaces through a process called microbiologically influenced corrosion (MIC). However, the mechanisms of MIC, whereby methanogens oxidize zerovalent iron (Fe), are largely unknown. In this study, Fe-corroding Methanococcus maripaludis strain OS7 and its derivative (strain OS7mut1) defective in Fe-corroding activity were isolated. Genomic analysis of these strains demonstrated that the strain OS7mut1 contained a 12-kb chromosomal deletion. The deleted region, termed "MIC island", encoded the genes for the large and small subunits of a [NiFe] hydrogenase, the TatA/TatC genes necessary for the secretion of the [NiFe] hydrogenase, and a gene for the hydrogenase maturation protease. Thus, the [NiFe] hydrogenase may be secreted outside the cytoplasmic membrane, where the [NiFe] hydrogenase can make direct contact with Fe, and oxidize it, generating hydrogen gas: Fe + 2 H → Fe + H. Comparative analysis of extracellular and intracellular proteomes of strain OS7 supported this hypothesis. The identification of the MIC genes enables the development of molecular tools to monitor epidemiology, and to perform surveillance and risk assessment of MIC-inducing M. maripaludis.
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http://dx.doi.org/10.1038/s41598-018-33541-5 | DOI Listing |
Proc Natl Acad Sci U S A
December 2024
Department of Pharmaceutical Analysis, School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, People's Republic of China.
Inflammatory bowel disease (IBD) is often associated with excessive inflammatory response and highly dysregulated gut microbiota. Traditional treatments utilize drugs to manage inflammation, potentially with probiotic therapy as an adjuvant. However, current standard practices often suffer from detrimental side effects, low bioavailability, and unsatisfactory therapeutic outcomes.
View Article and Find Full Text PDFChem Commun (Camb)
November 2024
Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
The ability of hydrogenase enzymes to activate H with excellent selectivity leads to many interesting possibilities for biotechnology driven by H as a clean reductant. Here, we review examples where hydrogenase enzymes have been used to drive native and non-native hydrogenation reactions in solution or as part of a redox cascade on a conductive support, with a focus on the developments we have contributed to this field. In all of the examples discussed, hydrogenation reactions are enabled by coupled redox reactions: the oxidation of H at a hydrogenase active site, linked electronically ( relay clusters in the enzyme and/or conductive support) to the site of a reduction reaction, and we note how this parallels developments in site-separated reactivity in heterogeneous catalysis.
View Article and Find Full Text PDFJ Am Chem Soc
November 2024
Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany.
[NiFe]-hydrogenases catalyze the reversible activation of H using a unique NiFe(CN)CO metal site, which is assembled by a sophisticated multiprotein machinery. The [4Fe-4S] cluster-containing HypCD complex, which possesses an ATPase activity with a hitherto unknown function, serves as the hub for the assembly of the Fe(CN)CO subfragment. HypCD is also thought to be responsible for the subsequent transfer of the iron fragment to the apo-form of the catalytic hydrogenase subunit, but the underlying mechanism has remained unexplored.
View Article and Find Full Text PDFFEMS Microbiol Ecol
November 2024
Department of Plant Physiology, UPSC, Umeå University, 90187 Umeå, Sweden.
Uptake hydrogenase (Hup) recycles H2 formed by nitrogenase during nitrogen fixation, thereby preserving energy. Among root nodule bacteria, most rhizobial strains examined are Hup-, while only one Hup- Frankia inoculum had been identified. Previous analyses had led to the identification of two different [NiFe] hydrogenase syntons.
View Article and Find Full Text PDFJ Biol Chem
October 2024
Biosciences Center, National Renewable Energy Lab, Golden, Colorado, USA. Electronic address:
The HoxEFUYH complex of Synechocystis PCC 6803 (S. 6803) consists of a HoxEFU ferredoxin:NAD(P)H oxidoreductase subcomplex and a HoxYH [NiFe]-hydrogenase subcomplex that catalyzes reversible H oxidation. Prior studies have suggested that the presence of HoxE is required for reactivity with ferredoxin; however, it is unknown how HoxE is functionally integrated into the electron transfer network of the HoxEFU:ferredoxin complex.
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