GO:0008794 arsenate reductase (glutaredoxin) activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0008794 describes the enzymatic reduction of arsenate [As(V)] to arsenite [As(III)] using reduced glutaredoxin as the electron donor.
• The electron flow is NADPH → glutathione reductase → glutathione → glutaredoxin → arsenate reductase, linking arsenic detoxification to cellular redox homeostasis.
• Arsenate reductases with this activity are found in bacteria, cyanobacteria, yeast, plants, and even human phosphatases such as Cdc25B/C.
• Some arsenate reductases are metallophosphoesterases that evolved to catalyze redox reactions, blurring the line between phosphatases and reductases.
• Studying this activity is relevant for arsenic bioremediation, biosensing, and understanding arsenic toxicity and carcinogenicity.
• CRISPR-based knockout, point mutation, and overexpression models enable causal dissection of arsenate reductase function in vivo.
Description
Arsenate reductase (glutaredoxin) activity, encoded by the Gene Ontology term GO:0008794, catalyzes the reduction of arsenate [As(V)] to arsenite [As(III)] using reduced glutaredoxin as the electron donor. This activity is a key step in arsenic detoxification and redox cycling in diverse organisms, from bacteria to humans. The reaction is part of a larger electron transfer chain that couples NADPH oxidation to arsenate reduction via glutathione and glutaredoxin. Understanding this activity is important because arsenic is a widespread environmental toxicant and carcinogen, and microbial arsenate reduction influences arsenic mobility and bioremediation. Moreover, human enzymes such as Cdc25B and Cdc25C phosphatases exhibit adventitious arsenate reductase activity, suggesting links to cell cycle regulation and cancer. The study of GO:0008794 therefore spans microbiology, environmental science, and human disease research.
arsenate reductase (glutaredoxin) activity At A Glance
| GO ID | GO:0008794 |
|---|---|
| GO term | arsenate reductase (glutaredoxin) activity |
| Ontology | molecular_function |
| Synonym | glutaredoxin:arsenate oxidoreductase activity |
| Major function | Reduction of arsenate to arsenite using reduced glutaredoxin as electron donor |
| Electron donor | Glutaredoxin (reduced) |
| Electron flow | NADPH → glutathione reductase → glutathione → glutaredoxin → arsenate reductase |
| Reaction | arsenate + reduced glutaredoxin = arsenite + oxidized glutaredoxin |
What Is GO:0008794?
GO:0008794 defines a molecular function: the catalysis of the reaction arsenate + reduced glutaredoxin = arsenite + oxidized glutaredoxin. In this reaction, glutaredoxin serves as the electron donor for arsenate reduction, and the overall electron flow is from NADPH through glutathione reductase, glutathione, and glutaredoxin to arsenate reductase. The term is synonymous with glutaredoxin:arsenate oxidoreductase activity and is classified under molecular_function in the Gene Ontology.
Why Is arsenate reductase (glutaredoxin) activity Important in Cell Biology?
GO:0008794 is important because it directly mediates arsenic detoxification and influences arsenic speciation in the environment. In microorganisms, this activity contributes to arsenic resistance and can be harnessed for bioremediation and biosensing. In higher organisms, including humans, arsenate reductase activity can be associated with phosphatases such as Cdc25B/C, linking arsenic metabolism to cell cycle regulation and potentially cancer. The enzyme's dual roles in redox and phosphate metabolism highlight evolutionary connections between distinct catalytic activities. Thus, studying GO:0008794 provides insights into fundamental redox biology, environmental toxicology, and human disease mechanisms.
• Enables microbial arsenic detoxification by converting arsenate to arsenite, which can be extruded or sequestered.
• Contributes to arsenic biogeochemistry and mobility in contaminated environments.
• Provides a basis for arsenic biosensors that exploit inhibition of phosphatase activity.
• Links arsenic exposure to human cell cycle regulation via Cdc25 phosphatases.
• Represents an example of enzyme evolution from metallophosphoesterases to redox catalysts.
• Involved in plant responses to arsenic stress, as shown in sweet potato.
• Studied in cyanobacteria to understand redox coupling with glutaredoxin.
• Used in yeast models to dissect arsenate reductase roles in stress response.
• Potential target for enhancing phytoremediation or bioremediation strategies.
• Relevant to understanding arsenic carcinogenicity and toxicity mechanisms.
Mechanism, Genes and Research Methods
Substrate Binding and Electron Transfer
In simple terms: The enzyme grabs arsenate and receives electrons from glutaredoxin to convert it to arsenite.
Arsenate reductase binds arsenate and reduced glutaredoxin, facilitating electron transfer from the glutaredoxin active site to arsenate. The reaction produces arsenite and oxidized glutaredoxin, which is then recycled by glutathione. Structural and kinetic studies of bacterial and cyanobacterial enzymes have revealed key residues involved in substrate binding and catalysis.
Coupling to Glutathione and NADPH
In simple terms: The electrons come from NADPH via glutathione and glutaredoxin.
The overall electron flow is NADPH → glutathione reductase → glutathione → glutaredoxin → arsenate reductase. Glutathione reductase reduces oxidized glutathione using NADPH, maintaining a pool of reduced glutathione that in turn reduces glutaredoxin. This coupling ensures a continuous supply of electrons for arsenate reduction and links the activity to cellular redox status.
Enzyme Diversity and Evolution
In simple terms: Different organisms have different versions of this enzyme, some evolved from phosphatases.
Arsenate reductases with glutaredoxin-dependent activity are found in bacteria, cyanobacteria, yeast, plants, and humans. Some are metallophosphoesterases that evolved to catalyze redox reactions, as shown for Rufibacter tibetensis. Human Cdc25B and Cdc25C phosphatases exhibit adventitious arsenate reductase activity, indicating evolutionary links between phosphatase and reductase functions.
Physiological Roles and Regulation
In simple terms: The enzyme helps cells cope with arsenic and is controlled by arsenic exposure and redox signals.
In Schizosaccharomyces pombe, arsenate reductase activity is induced upon arsenate treatment and contributes to resistance. In bacteria, the activity is part of arsenic resistance operons. The enzyme's dependence on glutaredoxin ties its function to glutathione homeostasis and oxidative stress responses.
Key Genes Involved in GO:0008794 arsenate reductase (glutaredoxin) activity
The following genes and proteins are directly associated with arsenate reductase (glutaredoxin) activity or its electron transfer partners, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| arsC (bacterial) | Arsenate reductase, reduces arsenate to arsenite | Model for bacterial arsenic resistance and bioremediation |
| Cdc25B (human) | Phosphatase with adventitious arsenate reductase activity | Links arsenic to cell cycle regulation and cancer |
| Cdc25C (human) | Phosphatase with adventitious arsenate reductase activity | Potential target in cancer and arsenic toxicity |
| Rufibacter tibetensis arsC | Metallophosphoesterase evolved for redox catalysis | Study of enzyme evolution |
| Enterobacter cloacae arsC | Arsenate reductase for arsenic biotransformation | Bioremediation applications |
| Sweet potato arsenate reductase | Plant enzyme with phosphatase activity | Plant arsenic stress responses |
| Synechocystis sp. PCC 6803 arsC | Glutaredoxin/arsenate reductase couple | Redox studies in cyanobacteria |
| Schizosaccharomyces pombe arsC | Arsenate reductase involved in stress response | Yeast model for arsenic detoxification |
| Thermus thermophilus arsC | Thermostable arsenate reductase | Biosensor development |
| Glutaredoxin (various) | Electron donor for arsenate reductase | Redox coupling |
| Glutathione reductase | Reduces glutathione to supply electrons | Electron flow chain |
| Glutathione | Redox buffer and electron carrier | Cellular redox homeostasis |
| NADPH | Primary electron source | Redox metabolism |
| Pseudomonas sp. arsC | Cytosolic arsenate reductase | Environmental arsenic cycling |
| Arsenate reductase homologs | Diverse enzymes with similar activity | Comparative enzymology |
| Phosphatase domains | Structural scaffolds for arsenate reduction | Evolutionary studies |
How Is arsenate reductase (glutaredoxin) activity Regulated?
The activity of arsenate reductase (glutaredoxin) is regulated at multiple levels. In bacteria, expression of arsenate reductase genes is often controlled by ArsR repressors that sense arsenite and arsenate. In Schizosaccharomyces pombe, arsenate treatment induces the activity, suggesting transcriptional or post-translational regulation. The enzyme's dependence on reduced glutaredoxin links its activity to the glutathione/glutathione reductase system, which is sensitive to cellular redox state and oxidative stress. Additionally, some human phosphatases like Cdc25B/C exhibit arsenate reductase activity that may be modulated by phosphorylation and cell cycle signals.
arsenate reductase (glutaredoxin) activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| Cdc25B | Cancer, cell cycle dysregulation | Human cell line knockout/overexpression |
| Cdc25C | Cancer, arsenic toxicity | CRISPR point mutation in cancer cells |
| Bacterial arsC | Arsenic resistance, infectious disease | Bacterial knockout and complementation |
| Yeast arsC | Arsenic stress response | Yeast knockout and overexpression |
| Plant arsenate reductase | Phytoremediation, plant stress | Plant knock-in/overexpression |
Arsenic Toxicity and Cancer
Arsenic is a human carcinogen, and its reduction from arsenate to arsenite is a key activation step. Human Cdc25B and Cdc25C phosphatases possess adventitious arsenate reductase activity, potentially linking arsenic exposure to cell cycle dysregulation and cancer. Understanding this activity may inform risk assessment and therapeutic strategies.
Infectious Diseases and Microbial Resistance
Bacterial arsenate reductases contribute to arsenic resistance, which can affect pathogen survival in arsenic-rich environments and influence treatment outcomes. Targeting these enzymes could help overcome resistance in certain contexts.
Environmental Health and Bioremediation
Microbial arsenate reductase activity influences arsenic mobility and toxicity in water and soil, impacting human health through drinking water contamination. Harnessing this activity for bioremediation is an active area of research.
From arsenate reductase (glutaredoxin) activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of arsenate reductase increase arsenic sensitivity? | CRISPR knockout in bacterial or yeast cells |
| Does a point mutation in the active site abolish activity? | CRISPR point mutation in arsC |
| Can human Cdc25B arsenate reductase activity be separated from phosphatase activity? | Knock-in of mutant Cdc25B in human cells |
| How does overexpression affect arsenic detoxification? | Overexpression of arsC in bacteria or plants |
| What is the subcellular localization of the enzyme? | Tagged knock-in with fluorescent protein |
| Can the enzyme be used as a biosensor? | Engineered Thermus thermophilus arsC |
How to Study the arsenate reductase (glutaredoxin) activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzyme activity assay | Arsenate reduction rate | Kinetic characterization |
| X-ray crystallography | Three-dimensional structure | Active site analysis |
| Site-directed mutagenesis | Role of specific residues | Mechanistic studies |
| RNA-seq | Transcriptional response to arsenic | Stress response profiling |
| CRISPR knockout | Loss-of-function phenotype | Gene function in vivo |
| Overexpression | Gain-of-function effects | Bioremediation and resistance |
| Biosensor assay | Arsenic detection | Environmental monitoring |
| Phylogenetic analysis | Evolutionary relationships | Enzyme family classification |
Enzymatic Activity Assays
Arsenate reductase activity is typically measured by monitoring the reduction of arsenate to arsenite using coupled assays with glutathione reductase and NADPH. These assays can be adapted for high-throughput screening and biosensor development.
Structural and Biophysical Methods
X-ray crystallography, NMR, and molecular dynamics simulations have been used to elucidate the structure and catalytic mechanism of arsenate reductases. These methods reveal substrate binding sites and conformational changes during catalysis.
Genetic and Genomic Approaches
Knockout, knockdown, and overexpression studies in bacteria, yeast, and human cells help determine the physiological roles of arsenate reductases. RNA-seq and proteomics can profile global responses to arsenic exposure.
Biosensing and Environmental Monitoring
Engineered arsenate reductases can be used in biosensors for arsenic detection, exploiting inhibition of phosphatase activity or redox changes. Such tools are valuable for environmental monitoring.
How CRISPR Can Be Used to Study GO:0008794 arsenate reductase (glutaredoxin) activity
Knockout
CRISPR knockout of arsenate reductase genes in bacteria, yeast, or human cells can reveal their contribution to arsenic resistance and detoxification. For example, knocking out arsC in Schizosaccharomyces pombe increases arsenate sensitivity.
Point Mutation
Introducing point mutations in catalytic residues of arsenate reductase can dissect the mechanism and separate redox activity from phosphatase activity. This is particularly useful for human Cdc25B/C to distinguish arsenate reduction from phosphatase function.
Knock-in
Knock-in of tagged or mutant arsenate reductase allows tracking of localization and interaction partners in live cells. It can also be used to express the enzyme under native or heterologous promoters for functional studies.
Overexpression
Overexpression of arsenate reductase genes can enhance arsenic detoxification and is a strategy for bioremediation. In plants, overexpression may improve arsenic tolerance and accumulation for phytoremediation.
How EDITGENE Supports arsenate reductase (glutaredoxin) activity Research
Researchers studying arsenate reductase (glutaredoxin) activity-related genes often need to determine whether a candidate gene is causally involved in arsenic detoxification, redox regulation, or disease. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for arsenate reductase (glutaredoxin) activity research.
Frequently Asked Questions About arsenate reductase (glutaredoxin) activity
What is arsenate reductase (glutaredoxin) activity?
It is the enzymatic activity that reduces arsenate to arsenite using reduced glutaredoxin as the electron donor, encoded by GO:0008794.
What genes are involved in arsenate reductase (glutaredoxin) activity?
Genes include bacterial arsC, human Cdc25B and Cdc25C, and homologs in yeast, plants, and cyanobacteria.
What is the reaction catalyzed by GO:0008794?
The reaction is arsenate + reduced glutaredoxin = arsenite + oxidized glutaredoxin.
How is arsenate reductase activity measured?
It is typically measured using coupled enzyme assays with glutathione reductase and NADPH, monitoring arsenite formation.
Why is arsenate reductase important for human health?
It is involved in arsenic detoxification and may link arsenic exposure to cancer through Cdc25 phosphatases.
Can arsenate reductase be used for bioremediation?
Yes, microbial arsenate reductases are studied for arsenic bioremediation and biosensing.
What is the electron flow for arsenate reductase?
The flow is NADPH → glutathione reductase → glutathione → glutaredoxin → arsenate reductase.
Are there human enzymes with arsenate reductase activity?
Yes, human Cdc25B and Cdc25C phosphatases exhibit adventitious arsenate reductase activity.
How can CRISPR be used to study arsenate reductase?
CRISPR knockout, point mutation, knock-in, and overexpression models allow functional dissection in various organisms.
What model organisms are used to study GO:0008794?
Bacteria, cyanobacteria, yeast, plants, and human cell lines are commonly used.
Conclusion
GO:0008794, arsenate reductase (glutaredoxin) activity, is a critical enzymatic function that couples arsenic detoxification to cellular redox metabolism. Its presence across diverse organisms and its link to human phosphatases underscore its broad biological significance. Continued research using CRISPR and other advanced tools will further illuminate its mechanisms and applications in environmental and biomedical fields.
References
- 1. Puopolo R et al.. 2022. A New Strategy for As(V) Biosensing Based on the Inhibition of the Phosphatase Activity of the Arsenate Reductase from Thermus thermophilus.. Int J Mol Sci 23(6) PMID: 35328363
- 2. Srivastava D et al.. 2010. Pentavalent arsenate reductase activity in cytosolic fractions of Pseudomonas sp., isolated from arsenic-contaminated sites of Tezpur, Assam.. Appl Biochem Biotechnol 162(3):766-79 PMID: 19950002
- 3. Bhattacharjee H et al.. 2010. Adventitious arsenate reductase activity of the catalytic domain of the human Cdc25B and Cdc25C phosphatases.. Biochemistry 49(4):802-9 PMID: 20025242
- 4. Shen J et al.. 2024. Arsenate reductase of Rufibacter tibetensis is a metallophosphoesterase evolved to catalyze redox reactions.. Mol Microbiol 122(2):201-212 PMID: 38922722
- 5. Bhati R et al.. 2023. Structural-functional analysis and molecular characterization of arsenate reductase from Enterobacter cloacae RSC3 for arsenic biotransformation.. 3 Biotech 13(9):305 PMID: 37593205
- 6. Chan YH et al.. 2011. An arsenate reductase homologue possessing phosphatase activity from sweet potato (Ipomoea batatas [L.] Lam): kinetic studies and characterization.. J Agric Food Chem 59(7):3087-91 PMID: 21388125
- 7. Kim SG et al.. 2012. Redox, mutagenic and structural studies of the glutaredoxin/arsenate reductase couple from the cyanobacterium Synechocystis sp. PCC 6803.. Biochim Biophys Acta 1824(2):392-403 PMID: 22155275
- 8. Salgado A et al.. 2012. Response to arsenate treatment in Schizosaccharomyces pombe and the role of its arsenate reductase activity.. PLoS One 7(8):e43208 PMID: 22912829
