Purification and Characterization of Sulfide:Quinone Oxidoreductase from an Acidophilic Iron-Oxidizing Bacterium,<i>Acidithiobacillus ferrooxidans</i>

Wakai, Satoshi; Tsujita, Mizuho; Kikumoto, Mei; Manchur, Mohammed Abul; Kanao, Tadayoshi; Kamimura, Kazuo

doi:10.1271/bbb.70332

Cited by 27 publications

(30 citation statements)

References 41 publications

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“…The latter is a candidate enzyme for the thiosulfate oxidation of H 2 -grown H. thermophilus cells and its soluble extracts, because Sqr often associates with the membrane and apparently does not have oxidation activity for thiosulfate as a substrate. 12) In addition, microarray analysis revealed that the sox genes were sufficiently expressed in the H 2 -grown H. thermophilus cells (unpublished observation), further indicating the presence of Sox proteins as thiosulfate oxidizing enzymes.…”

mentioning

confidence: 92%

Thiosulfate Oxidation by a Thermo-Neutrophilic Hydrogen-Oxidizing Bacterium,Hydrogenobacter thermophilus

Sano

Kameya

Wakai

et al. 2010

Bioscience, Biotechnology, and Biochemistry

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confidence: 92%

Thiosulfate Oxidation by a Thermo-Neutrophilic Hydrogen-Oxidizing Bacterium,Hydrogenobacter thermophilus

Sano

Kameya

Wakai

et al. 2010

Bioscience, Biotechnology, and Biochemistry

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“…The oxidation of ferrous iron by this bacterium has been previously examined in great detail (3)(4)(5)(6). Some enzymes or proteins previously found and thought to be involved in the aerobic oxidation of RISCs by A. ferrooxidans include thiosulfate dehydrogenase (7,8), thiosulfate:quinone reductase (9), sulfur dioxygenase (10), sulfur:ferric ion oxidoreductase (11), sulfite:ferric ion oxidoreductase (12), a rhodanese-like protein (2,(13)(14)(15), sulfide:quinone oxidoreductase (SQR) (16,17), and tetrathionate hydrolase (TTH) (18). RISCs are chemically reactive, and thus, some reactions can occur nonenzymatically.…”

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confidence: 99%

“…We proposed that sulfide and tetrathionate are intermediates of sulfur oxidation in A. ferrooxidans and are further metabolized by TTH and SQR (16)(17)(18). A bd-type ubiquinol oxidase is also involved in sulfur oxidation (19).…”

mentioning

confidence: 99%

Tetrathionate-Forming Thiosulfate Dehydrogenase from the Acidophilic, Chemolithoautotrophic Bacterium Acidithiobacillus ferrooxidans

Kikumoto

Nogami

Kanao

et al. 2013

Appl Environ Microbiol

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bThiosulfate dehydrogenase is known to play a significant role in thiosulfate oxidation in the acidophilic, obligately chemolithoautotroph, Acidithiobacillus ferrooxidans. Enzyme activity measured using ferricyanide as the electron acceptor was detected in cell extracts of A. ferrooxidans ATCC 23270 grown on tetrathionate or sulfur, but no activity was detected in ferrous iron-grown cells. The enzyme was enriched 63-fold from cell extracts of tetrathionate-grown cells. Maximum enzyme activity (13.8 U mg ؊1 ) was observed at pH 2.5 and 70°C. The end product of the enzyme reaction was tetrathionate. The enzyme reduced neither ubiquinone nor horse heart cytochrome c, which serves as an electron acceptor. A major protein with a molecular mass of ϳ25 kDa was detected in the partially purified preparation. Heme was not detected in the preparation, according to the results of spectroscopic analysis and heme staining. The open reading frame of AFE_0042 was identified by BLAST by using the N-terminal amino acid sequence of the protein. The gene was found within a region that was previously noted for sulfur metabolismrelated gene clustering. The recombinant protein produced in Escherichia coli had a molecular mass of ϳ25 kDa and showed thiosulfate dehydrogenase activity, with maximum enzyme activity (6.5 U mg ؊1 ) observed at pH 2.5 and 50°C.

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“…As for the two sqr genes, they behaved the same way but with slightly larger changes for AFE_0267 than for AFE_1792. However, most of the research on sulfide metabolism has been focused on AFE_1792 (31)(32)(33)(34). In our study, the qRT-PCR data indicated that AFE_0267 might also play a key role in H 2 S metabolism after elemental sulfur enters the cells.…”

Section: Resultsmentioning

confidence: 63%

“…The study on oxidation of RISCs by A. ferrooxidans has proved particularly challenging, and the proposed models of sulfur metabolism were built based merely on the bioinformatic predictions of its genome sequence, coupled with analyses of its transcriptomic or proteomic experimental data (4,5). The functions of most genes involved in the oxidation of RISCs remain uncertain, though some genes have been characterized by cloning and expressing them in Escherichia coli (12,13,32,36). Considering the marked differences in the growth requirements between the genera Acidithiobacillus and Escherichia, the periplasmic or outer membrane proteins of A. ferrooxidans, such as some enzymes and electron carriers related to sulfur oxidation, might find it hard to function in E. coli.…”

Section: Discussionmentioning

confidence: 99%

Construction and Characterization of tetH Overexpression and Knockout Strains of Acidithiobacillus ferrooxidans

Liu

Wang

et al. 2014

J Bacteriol

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Acidithiobacillus ferrooxidans is a major participant in consortia of microorganisms used for bioleaching. It can obtain energy from the oxidation of Fe 2؉ , H 2 , S 0 , and various reduced inorganic sulfur compounds (RISCs). Tetrathionate is a key intermediate during RISC oxidation, hydrolyzed by tetrathionate hydrolase (TetH), and used as sole energy source. In this study, a tetH knockout (⌬tetH) mutant and a tetH overexpression strain were constructed and characterized. The tetH overexpression strain grew better on sulfur and tetrathionate and possessed a higher rate of tetrathionate utilization and TetH activity than the wild type. However, its cell yields on tetrathionate were much lower than those on sulfur. The ⌬tetH mutant could not grow on tetrathionate but could proliferate on sulfur with a lower cell yield than the wild type's, which indicated that tetrathionate hydrolysis is mediated only by TetH, encoded by tetH. The ⌬tetH mutant could survive in ferrous medium with an Fe 2؉ oxidation rate similar to that of the wild type. For the tetH overexpression strain, the rate was relatively higher than that of the wild type. The reverse transcription-quantitative PCR (qRT-PCR) results showed that tetH and doxD2 acted synergistically, and doxD2 was considered important in thiosulfate metabolism. Of the two sqr genes, AFE_0267 seemed to play as important a role in sulfide oxidation as AFE_1792. This study not only provides a substantial basis for studying the function of the tetH gene but also may serve as a model to clarify other candidate genes involved in sulfur oxidation in this organism.

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Purification and Characterization of Sulfide:Quinone Oxidoreductase from an Acidophilic Iron-Oxidizing Bacterium,Acidithiobacillus ferrooxidans

Cited by 27 publications

References 41 publications

Thiosulfate Oxidation by a Thermo-Neutrophilic Hydrogen-Oxidizing Bacterium,Hydrogenobacter thermophilus

Thiosulfate Oxidation by a Thermo-Neutrophilic Hydrogen-Oxidizing Bacterium,Hydrogenobacter thermophilus

Tetrathionate-Forming Thiosulfate Dehydrogenase from the Acidophilic, Chemolithoautotrophic Bacterium Acidithiobacillus ferrooxidans

Construction and Characterization of tetH Overexpression and Knockout Strains of Acidithiobacillus ferrooxidans

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