Incorporation of tellurium into amino acids and proteins in a tellurium-tolerant fungi

Ramadan, Shadia E.; Razak, A. A.; Ragab, Ahmed; El-Meleigy, M. A.

doi:10.1007/bf02917437

Cited by 76 publications

(40 citation statements)

References 14 publications

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“…2(d) the longer delay of 34.2 ms optimized for the smaller coupling constant was used to enhance the less sensitive b-protons. Similar results (not shown) were obtained with tellurophene (6), which also has a large and a small coupling constant.…”

Section: Resultssupporting

confidence: 91%

1H-{125Te} indirect detection in nuclear magnetic resonance spectra of organotellurium compounds

et al. 1997

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Section: Resultssupporting

confidence: 91%

1H-{125Te} indirect detection in nuclear magnetic resonance spectra of organotellurium compounds

et al. 1997

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“…Indeed there have been reports of sulfur globule formation occurring in several magnetotactic bacteria, although the mechanism is still unknown (3,36). There are literature reports of tellurium substitution of sulfur in amino acids such as cysteine in tellurium-resistant fungi (26,31). Therefore, as tellurium can be considered to be an analogue to sulfur, we tentatively suggest that the tellurium nanorods described in this report are analogues to sulfur globules.…”

Section: Discussionmentioning

confidence: 56%

Simultaneously Discrete Biomineralization of Magnetite and Tellurium Nanocrystals in Magnetotactic Bacteria

Tanaka

Arakaki

Staniland

et al. 2010

Appl Environ Microbiol

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Magnetotactic bacteria synthesize intracellular magnetosomes comprising membrane-enveloped magnetite crystals within the cell which can be manipulated by a magnetic field. Here, we report the first example of tellurium uptake and crystallization within a magnetotactic bacterial strain, Magnetospirillum magneticum AMB-1. These bacteria independently crystallize tellurium and magnetite within the cell. This is also highly significant as tellurite (TeO 3 2؊ ), an oxyanion of tellurium, is harmful to both prokaryotes and eukaryotes. Additionally, due to its increasing use in high-technology products, tellurium is very precious and commercially desirable. The use of microorganisms to recover such molecules from polluted water has been considered as a promising bioremediation technique. However, cell recovery is a bottleneck in the development of this approach. Recently, using the magnetic property of magnetotactic bacteria and a cell surface modification technology, the magnetic recovery of Cd 2؉ adsorbed onto the cell surface was reported. Crystallization within the cell enables approximately 70 times more bioaccumulation of the pollutant per cell than cell surface adsorption, while utilizing successful recovery with a magnetic field. This fascinating dual crystallization of magnetite and tellurium by magnetotactic bacteria presents an ideal system for both bioremediation and magnetic recovery of tellurite.

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“…Selenomethionine is then randomly incorporated into proteins due to the editing tolerance of methionyl-tRNA synthetase (10,35). Although the intracellular fate of telluromethionine is less well known, the existence of telluromethionine, methyltelluromethionine, and, to a lesser extent, tellurocysteine has been reported from the cultivation of yeast and bacteria in the presence of high concentrations of Te(IV) (42,71). Telluromethionine has also been shown to be able to replace methionine residues in about 40% of the copies of the protein dihydrofolate reductase in E. coli (3).…”

Section: Discussionmentioning

confidence: 99%

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae

et al. 2010

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Despite a century of research and increasing environmental and human health concerns, the mechanistic basis of the toxicity of derivatives of the metalloid tellurium, Te, in particular the oxyanion tellurite, Te(IV), remains unsolved. Here, we provide an unbiased view of the mechanisms of tellurium metabolism in the yeast Saccharomyces cerevisiae by measuring deviations in Te-related traits of a complete collection of gene knockout mutants. Reduction of Te(IV) and intracellular accumulation as metallic tellurium strongly correlated with loss of cellular fitness, suggesting that Te(IV) reduction and toxicity are causally linked. The sulfate assimilation pathway upstream of Met17, in particular, the sulfite reductase and its cofactor siroheme, was shown to be central to tellurite toxicity and its reduction to elemental tellurium. Gene knockout mutants with altered Te(IV) tolerance also showed a similar deviation in tolerance to both selenite and, interestingly, selenomethionine, suggesting that the toxicity of these agents stems from a common mechanism. We also show that Te(IV) reduction and toxicity in yeast is partially mediated via a mitochondrial respiratory mechanism that does not encompass the generation of substantial oxidative stress. The results reported here represent a robust base from which to attack the mechanistic details of Te(IV) toxicity and reduction in a eukaryotic organism.

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Incorporation of tellurium into amino acids and proteins in a tellurium-tolerant fungi

Cited by 76 publications

References 14 publications

1H-{125Te} indirect detection in nuclear magnetic resonance spectra of organotellurium compounds

1H-{125Te} indirect detection in nuclear magnetic resonance spectra of organotellurium compounds

Simultaneously Discrete Biomineralization of Magnetite and Tellurium Nanocrystals in Magnetotactic Bacteria

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae

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