GO:0052851 ferric-chelate reductase (NADPH) activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0052851 describes ferric-chelate reductase (NADPH) activity, the enzyme activity that reduces Fe(III)-siderophore complexes to Fe(II)-siderophore using NADPH as the electron donor.
• This activity is essential for iron acquisition in plants, fungi, and some bacteria, enabling them to extract iron from insoluble ferric chelates.
• In plants, the enzyme is a membrane-bound ferric-chelate reductase that is induced under iron deficiency and is inhibited by glyphosate.
• In Candida albicans, the activity is regulated by iron and copper levels, linking iron homeostasis to copper metabolism.
• The Leishmania amazonensis LFR1 protein is a bifunctional enzyme with both ferric iron reductase and NADPH oxidase activities, highlighting a dual role in iron reduction and redox signaling.
• Studying GO:0052851 requires combining biochemical assays, genetic models, and CRISPR-based editing to dissect its roles in iron metabolism and disease.
Description
Ferric-chelate reductase (NADPH) activity, defined by the Gene Ontology term GO:0052851, catalyzes the reduction of Fe(III)-siderophore complexes to Fe(II)-siderophore using NADPH as the electron donor. This activity is a critical step in iron acquisition for many organisms, as it converts insoluble ferric iron into a more soluble ferrous form that can be transported into cells. The enzyme is widely distributed across plants, fungi, and bacteria, and its study has revealed diverse physiological roles, from root iron uptake in plants to iron homeostasis in pathogenic fungi. In plants, ferric-chelate reductase activity is induced under iron deficiency and is essential for survival in alkaline soils where iron is poorly available. In the pathogenic yeast Candida albicans, the activity is regulated by iron and copper levels, suggesting a link between metal homeostasis and virulence. The Leishmania amazonensis LFR1 protein exhibits both ferric iron reductase and NADPH oxidase activities, indicating that this enzyme can participate in redox signaling beyond simple iron reduction. Understanding GO:0052851 is therefore important for researchers studying iron metabolism, host-pathogen interactions, and plant nutrition.
ferric-chelate reductase (NADPH) activity At A Glance
| GO ID | GO:0052851 |
|---|---|
| GO term | ferric-chelate reductase (NADPH) activity |
| Ontology | molecular_function |
| Synonym | ferric chelate reductase activity; ferric reductase, NADPH-dependent activity; iron chelate reductase activity |
| Major function | Reduction of Fe(III)-siderophore to Fe(II)-siderophore using NADPH as electron donor |
| Reaction | 2 a Fe(II)-siderophore + NADP+ + H+ = 2 a Fe(III)-siderophore + NADPH |
| Cofactor | NADPH |
| Subcellular location | Membrane-associated in plants and fungi; cell-associated in Candida albicans |
| Regulation | Induced by iron deficiency in plants; regulated by iron and copper levels in Candida albicans |
What Is GO:0052851?
GO:0052851 is a molecular function term that describes the catalysis of the reaction: 2 a Fe(II)-siderophore + NADP+ + H+ = 2 a Fe(III)-siderophore + NADPH. In other words, it is the enzyme activity that uses NADPH to reduce ferric iron (Fe(III)) bound to a siderophore, converting it to ferrous iron (Fe(II)). This activity is synonymous with ferric chelate reductase activity, ferric reductase, NADPH-dependent activity, and iron chelate reductase activity.
Why Is ferric-chelate reductase (NADPH) activity Important in Cell Biology?
GO:0052851 is important because it governs a key step in iron acquisition, a process essential for the survival and virulence of many organisms. In plants, ferric-chelate reductase activity is critical for iron uptake from soil, and its deficiency leads to iron chlorosis and reduced crop yields. In pathogenic fungi such as Candida albicans, the activity is regulated by iron and copper, linking metal homeostasis to pathogenicity. In Leishmania amazonensis, the bifunctional LFR1 enzyme with ferric reductase and NADPH oxidase activities suggests a role in redox signaling and host-pathogen interactions. Moreover, ferric reductase activity has been detected in human intestinal cells and monocyte-macrophages, indicating potential roles in human iron metabolism and immunity. Thus, understanding this activity has implications for agriculture, infectious disease, and human health.
• Essential for iron acquisition in plants, enabling growth in iron-deficient soils.
• Inhibited by glyphosate, linking herbicide exposure to iron deficiency in crops.
• Regulated by iron and copper levels in Candida albicans, affecting metal homeostasis and virulence.
• Bifunctional ferric reductase/NADPH oxidase in Leishmania amazonensis suggests roles in redox signaling.
• Present in human intestinal brush border membranes, indicating a role in dietary iron absorption.
• Activity in monocyte-macrophages is inhibited by iron and stimulated by differentiation, linking to immune function.
• Ferric reductase activity associated with dihydropteridine reductase suggests a link to neurotransmitter metabolism.
• ArsH protein from Acidithiobacillus ferrooxidans exhibits ferric reductase activity, expanding its role beyond arsenic resistance.
• Potential target for developing iron chelation therapies or improving crop iron content.
• Provides a model for studying electron transfer from NADPH to ferric chelates.
Molecular Mechanism of ferric-chelate reductase (NADPH) activity
Substrate Binding and Iron Chelate Recognition
In simple terms: The enzyme grabs onto iron that is tightly held by a molecule called a siderophore.
Ferric-chelate reductase (NADPH) activity begins with the binding of Fe(III)-siderophore complexes to the enzyme's active site. In plants, the enzyme is a membrane-bound ferric-chelate reductase that specifically recognizes ferric chelates and reduces them to ferrous chelates. The substrate specificity ensures that the enzyme acts on iron bound to siderophores or chelators, facilitating iron uptake.
Electron Transfer from NADPH
In simple terms: The enzyme uses NADPH to donate electrons to iron, changing it from a rusty form to a more usable form.
The catalytic mechanism involves the transfer of electrons from NADPH to the Fe(III) center, reducing it to Fe(II). This reaction is dependent on NADPH as the electron donor, as indicated by the GO definition and biochemical studies. In Leishmania amazonensis, the LFR1 protein exhibits both ferric iron reductase and NADPH oxidase activities, suggesting that electron transfer can also generate superoxide or other reactive oxygen species.
Cofactors and Redox Centers
In simple terms: The enzyme uses helper molecules like FAD or heme to move electrons.
Ferric-chelate reductases often contain flavin or heme cofactors that facilitate electron transfer. For example, the dihydropteridine reductase enzyme exhibits NADH-ferric reductase activity, indicating that redox cofactors can support this activity. The ArsH protein from Acidithiobacillus ferrooxidans also shows ferric reductase activity, likely utilizing a flavin cofactor.
Regulation by Iron and Copper Status
In simple terms: The enzyme's activity goes up or down depending on how much iron or copper is around.
In Candida albicans, ferric reductase activity is regulated in response to levels of iron and copper, ensuring metal homeostasis. In plants, the activity is induced under iron deficiency, allowing efficient iron acquisition. This regulation is critical for adapting to changing environmental metal availability.
Inhibition and Stimulation
In simple terms: Certain chemicals or conditions can block or boost the enzyme.
Glyphosate inhibits ferric reductase activity in iron-deficient sunflower roots, linking herbicide exposure to iron deficiency. In contrast, monocyte-macrophage ferric reductase activity is stimulated by cellular differentiation and inhibited by iron. These findings highlight the sensitivity of this activity to both environmental and physiological cues.
Key Genes Involved in GO:0052851 ferric-chelate reductase (NADPH) activity
The following genes and proteins are directly associated with ferric-chelate reductase (NADPH) activity or related ferric reductase functions.
| Gene | Major Role | Research Relevance |
|---|---|---|
| FRO2 (Arabidopsis thaliana) | Ferric-chelate reductase for iron uptake from soils | Model for plant iron deficiency responses |
| LFR1 (Leishmania amazonensis) | Bifunctional ferric iron reductase and NADPH oxidase | Role in iron reduction and redox signaling |
| Fre1p (Candida albicans) | Cell-associated ferric reductase regulated by iron and copper | Metal homeostasis and virulence |
| ArsH (Acidithiobacillus ferrooxidans) | Ferric reductase activity | Expands role beyond arsenic resistance |
| Dihydropteridine reductase (human) | NADH-ferric reductase activity | Link to neurotransmitter metabolism |
| Caco-2 brush border ferric reductase | Ferric reductase in intestinal cells | Dietary iron absorption |
| Monocyte-macrophage ferric reductase | Ferric reductase activity in immune cells | Iron and immune function |
| FRO homologs (various plants) | Ferric-chelate reduction | Crop iron nutrition |
| Ferric reductase (sunflower roots) | Iron deficiency-induced ferric reductase | Glyphosate inhibition |
| Ferric reductase (yeast) | Iron uptake | Fungal iron metabolism |
| Ferric reductase (bacteria) | Iron acquisition | Microbial iron reduction |
| NADPH oxidase (LFR1) | Superoxide production | Redox signaling |
| Ferric reductase (human enterocytes) | Iron absorption | Human iron homeostasis |
| Ferric reductase (macrophages) | Iron handling | Inflammation and immunity |
| Ferric reductase (plant roots) | Iron acquisition | Plant nutrition |
| Ferric reductase (Candida) | Iron and copper homeostasis | Fungal pathogenesis |
| Ferric reductase (Acidithiobacillus) | Iron reduction | Biotechnology |
How Is ferric-chelate reductase (NADPH) activity Regulated?
Ferric-chelate reductase (NADPH) activity is regulated at multiple levels. In plants, the activity is induced under iron deficiency, a response mediated by transcription factors such as FIT and bHLH proteins. In Candida albicans, the activity is regulated in response to levels of iron and copper, ensuring metal homeostasis. In monocyte-macrophages, the activity is inhibited by iron and stimulated by cellular differentiation. Additionally, glyphosate inhibits ferric reductase activity in sunflower roots, indicating environmental regulation. These regulatory mechanisms allow organisms to adapt to changing iron availability.
ferric-chelate reductase (NADPH) activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FRO2 | Iron deficiency chlorosis in plants | Arabidopsis knockout and overexpression lines |
| LFR1 | Leishmaniasis and redox signaling | Leishmania knockout and knock-in models |
| Fre1p | Candida infections and metal homeostasis | Candida albicans knockout strains |
| Dihydropteridine reductase | Neurotransmitter metabolism disorders | Human cell lines with point mutations |
| Ferric reductase (macrophage) | Iron overload and inflammation | Macrophage differentiation models |
Iron Deficiency and Plant Health
Ferric-chelate reductase activity is essential for plant iron uptake, and its deficiency leads to iron chlorosis, a condition characterized by yellowing leaves and reduced growth. Glyphosate inhibition of this activity can exacerbate iron deficiency in crops. Understanding this activity is crucial for developing iron-efficient crops.
Fungal Pathogenesis and Metal Homeostasis
In Candida albicans, ferric reductase activity is regulated by iron and copper, and its disruption may affect virulence. The enzyme is a potential target for antifungal therapy.
Parasitic Infections and Redox Signaling
Leishmania amazonensis LFR1 is a bifunctional ferric reductase/NADPH oxidase that may contribute to redox signaling and host-pathogen interactions. This dual activity could be targeted for antiparasitic drugs.
Human Iron Metabolism and Immunity
Ferric reductase activity in human intestinal cells and monocyte-macrophages suggests roles in dietary iron absorption and immune function. Dysregulation may contribute to iron-related disorders.
From ferric-chelate reductase (NADPH) activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does FRO2 knockout affect plant iron uptake? | Arabidopsis thaliana KO lines |
| Does LFR1 point mutation alter NADPH oxidase activity? | Leishmania amazonensis point-mutation knock-in |
| Does Fre1p overexpression increase iron reduction? | Candida albicans overexpression strains |
| Does dihydropteridine reductase ferric reductase activity require NADH? | Human cell lines with tagged knock-in |
| Does glyphosate inhibit ferric reductase in crops? | Sunflower root assays with glyphosate treatment |
| Does macrophage ferric reductase change with differentiation? | Monocyte-macrophage differentiation models |
How to Study the ferric-chelate reductase (NADPH) activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Ferrozine assay | Fe(II) production from Fe(III) reduction | Plant root ferric reductase activity |
| NADPH consumption assay | NADPH oxidation | Enzyme kinetics |
| RNA-seq | Gene expression changes | Iron deficiency responses |
| Proteomics | Protein abundance and modifications | Regulation by iron |
| CRISPR knockout | Loss of gene function | Plant and fungal models |
| Overexpression | Gain of function | Candida albicans |
| Fluorescence microscopy | Subcellular localization | Membrane targeting |
| Site-directed mutagenesis | Point mutations in catalytic residues | Mechanistic studies |
Biochemical Assays for Ferric Reductase Activity
Ferric reductase activity is typically measured using colorimetric assays that detect the formation of Fe(II) from Fe(III) chelates, often with ferrozine or bathophenanthroline disulfonate as the chromophore. These assays can be performed on cell lysates, membrane fractions, or intact cells.
Genetic Approaches: Knockout and Overexpression
Genetic models such as Arabidopsis FRO2 knockout and overexpression lines have been used to demonstrate the role of ferric-chelate reductase in iron uptake. Similarly, Candida albicans fre1 mutants have been used to study regulation by iron and copper.
Transcriptomics and Proteomics
RNA-seq and proteomics can reveal changes in ferric reductase gene expression under iron deficiency or other conditions. These methods help identify regulatory networks.
Imaging and Localization
Fluorescent tagging of ferric reductase proteins can reveal their subcellular localization, such as membrane association in plant roots.
How CRISPR Can Be Used to Study GO:0052851 ferric-chelate reductase (NADPH) activity
Knockout
CRISPR knockout of ferric reductase genes such as FRO2 in Arabidopsis or fre1 in Candida albicans can abolish ferric-chelate reductase activity, leading to iron deficiency phenotypes. These models are valuable for studying the physiological consequences of loss of function.
Point Mutation
Introducing point mutations in catalytic residues of ferric reductases, such as those in LFR1, can dissect the electron transfer mechanism and separate ferric reductase from NADPH oxidase activity.
Knock-in
Knock-in of tagged ferric reductase genes (e.g., GFP or FLAG) allows visualization and immunoprecipitation of the enzyme, facilitating localization and interaction studies.
Overexpression
Overexpression of ferric reductase genes can increase iron reduction capacity and has been used to enhance iron uptake in plants and fungi.
How EDITGENE Supports ferric-chelate reductase (NADPH) activity Research
Researchers studying ferric-chelate reductase (NADPH) activity-related genes often need to determine whether a candidate gene is causally involved in iron reduction, metal homeostasis, or related diseases. EDITGENE provides comprehensive CRISPR-based services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for ferric-chelate reductase (NADPH) activity research.
Frequently Asked Questions About ferric-chelate reductase (NADPH) activity
What is ferric-chelate reductase (NADPH) activity?
It is an enzyme activity defined by GO:0052851 that reduces Fe(III)-siderophore complexes to Fe(II)-siderophore using NADPH as the electron donor.
What genes are involved in ferric-chelate reductase (NADPH) activity?
Key genes include FRO2 in Arabidopsis, LFR1 in Leishmania, and fre1 in Candida albicans.
Why is ferric-chelate reductase important for plants?
It enables iron uptake from soil, and its deficiency causes iron chlorosis.
How is ferric-chelate reductase activity regulated?
It is induced by iron deficiency in plants and regulated by iron and copper levels in Candida albicans.
What diseases are associated with ferric-chelate reductase?
Iron deficiency in plants, fungal infections, and potentially human iron disorders.
What is the reaction catalyzed by GO:0052851?
2 Fe(II)-siderophore + NADP+ + H+ = 2 Fe(III)-siderophore + NADPH.
How can I measure ferric-chelate reductase activity?
Using colorimetric assays such as ferrozine that detect Fe(II) formation.
What model organisms are used to study ferric-chelate reductase?
Arabidopsis, Candida albicans, Leishmania, and human cell lines.
Is ferric-chelate reductase activity linked to glyphosate?
Yes, glyphosate inhibits ferric reductase activity in sunflower roots.
What CRISPR services are available for studying ferric-chelate reductase?
EDITGENE offers knockout, point mutation, knock-in, overexpression, library screening, and bioinformatics services.
Conclusion
Ferric-chelate reductase (NADPH) activity (GO:0052851) is a fundamental enzyme activity for iron acquisition in plants, fungi, and bacteria, with emerging roles in human iron metabolism and immunity. Its regulation by iron and copper, inhibition by glyphosate, and bifunctional activities in parasites highlight its broad biological significance. Researchers can leverage CRISPR-based models and biochemical assays to further dissect its mechanisms and therapeutic potential.
References
- 1. Rocco-Machado N et al.. 2019. Leishmania amazonensis ferric iron reductase (LFR1) is a bifunctional enzyme: Unveiling a NADPH oxidase activity.. Free Radic Biol Med 143:341-353 PMID: 31446054
- 2. Lee PL et al.. 2000. NADH-ferric reductase activity associated with dihydropteridine reductase.. Biochem Biophys Res Commun 271(3):788-95 PMID: 10814540
- 3. Partridge J et al.. 1998. Monocyte-macrophage ferric reductase activity is inhibited by iron and stimulated by cellular differentiation.. Biochem J 336 ( Pt 3)(Pt 3):541-3 PMID: 9841863
- 4. Ekmekcioglu C et al.. 1996. A ferric reductase activity is found in brush border membrane vesicles isolated from Caco-2 cells.. J Nutr 126(9):2209-17 PMID: 8814209
- 5. Robinson NJ et al.. 1999. A ferric-chelate reductase for iron uptake from soils.. Nature 397(6721):694-7 PMID: 10067892
- 6. Ozturk L et al.. 2008. Glyphosate inhibition of ferric reductase activity in iron deficient sunflower roots.. New Phytol 177(4):899-906 PMID: 18179601
- 7. Morrissey JA et al.. 1996. Candida albicans has a cell-associated ferric-reductase activity which is regulated in response to levels of iron and copper.. Microbiology (Reading) 142 ( Pt 3):485-492 PMID: 8868423
- 8. Mo H et al.. 2011. Ferric reductase activity of the ArsH protein from Acidithiobacillus ferrooxidans.. J Microbiol Biotechnol 21(5):464-9 PMID: 21617342
