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Pseudomonas seleniipraecipitans proteins potentially involved in selenite reduction
1United States Department of Agriculture-Agricultural Research Service, 2150-D Centre Avenue, Fort Collins, CO, 80526-8119, USA, william.hunter@ars.usda.gov.
Current Microbiology
|March 8, 2014
Summary
Pseudomonas seleniipraecipitans reduces toxic selenite to elemental selenium. This study identified glutathione reductase (GR) and thioredoxin reductase (ThxR) as key enzymes responsible for this crucial bioremediation process.
Area of Science:
- Environmental microbiology
- Biochemistry
- Bioremediation
Background:
- Pseudomonas seleniipraecipitans can detoxify selenite and selenate, crucial for environmental remediation.
- Previous research identified nitrate reductase for selenate reduction but not selenite reduction enzymes.
Purpose of the Study:
- Identify the specific proteins in P. seleniipraecipitans responsible for selenite reduction.
- Confirm the selenite reductase activity of identified enzymes using commercial sources.
Main Methods:
- Enzyme isolation using ammonium sulfate precipitation, hydrophobic interaction chromatography, and native PAGE.
- Proteomic analysis to identify proteins in active selenite-reducing fractions.
- Biochemical assays to confirm selenite reductase activity of isolated enzymes.
Main Results:
- Two active fractions (bands A and B) showing selenite reductase activity were isolated.
- Proteomics identified glutathione reductase (GR) in band A and thioredoxin reductase (ThxR) in band B.
- Commercial S. cerevisiae GR and E. coli ThxR confirmed selenite reduction to elemental selenium.
Conclusions:
- Glutathione reductase (GR) and thioredoxin reductase (ThxR) are confirmed selenite reductases.
- These enzymes are likely responsible for selenite detoxification in P. seleniipraecipitans.
- Findings support the use of P. seleniipraecipitans in biobarriers for selenium removal from water.
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