GO:1903135 cupric ion binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1903135 (cupric ion binding) is a molecular function defined as binding to a cupric ion, copper(2+).
• Cupric ion binding is distinct from cuprous ion binding and is often studied using diligand metal-ion buffers to control free Cu(2+).
• Classic studies identified cupric ion binding sites in serum albumin, myoglobin derivatives, and bovine pancreatic ribonuclease.
• Copper homeostasis proteins such as CopI can oxidize Cu(I) to Cu(II), linking cupric ion binding to redox biology.
• Cupric ions can selectively modulate protein-lipid interactions, as shown for TRAAK-phosphatidylserine binding.
• Dysregulated copper metabolism and cuproptosis are implicated in acute liver injury and other disease states.
Description
Cupric ion binding (GO:1903135) is a molecular function that describes the selective interaction of a protein or biomolecule with copper in its oxidized Cu(2+) state. This function is fundamental to copper homeostasis, redox chemistry, and metal-dependent signaling, and it is experimentally distinguished from binding to cuprous ion (Cu(+)) using defined metal-ion buffers. Because copper is both essential and potentially toxic, proteins that bind cupric ions are central to understanding how cells manage metal stress and how metal dysregulation contributes to disease. Researchers study cupric ion binding to define metal-coordination sites, to measure binding affinities, and to test whether copper binding alters protein structure, catalysis, or interactions with lipids and other partners. The term is therefore a key annotation for interpreting copper-dependent mechanisms across biochemistry, cell biology, and translational medicine.
cupric ion binding At A Glance
| GO ID | GO:1903135 |
|---|---|
| GO term | cupric ion binding |
| Ontology | molecular_function |
| Synonym | copper(2+) binding; Cu(2+) binding; Cu(II) binding |
| Definition | Binding to a cupric ion, copper(2+). |
| Major function | Selective interaction with Cu(2+) as a metal ligand, often in redox or transport proteins. |
| Related metal species | Cupric ion (Cu2+), distinct from cuprous ion (Cu+). |
| Experimental control | Diligand metal-ion buffers are used to control free Cu(2+) concentrations in binding assays. |
| Representative proteins | Serum albumin, myoglobin derivatives, ribonuclease, and multicopper proteins such as CopI. |
What Is GO:1903135?
According to the Gene Ontology, GO:1903135 (cupric ion binding) is defined as the binding to a cupric ion, copper(2+). It is a molecular function term with synonyms including copper(2+) binding, Cu(2+) binding, and Cu(II) binding. This function is distinct from binding to other copper species such as Cu(+), and it is typically assigned when a gene product physically interacts with Cu(2+) as a ligand.
Why Is cupric ion binding Important in Cell Biology?
Cupric ion binding is important because copper is a redox-active transition metal required for essential enzymes but toxic when unregulated. Proteins that bind Cu(2+) control copper availability, protect against oxidative damage, and mediate copper-dependent signaling and catalysis. Understanding this function helps explain how mutations or environmental factors that alter copper handling can contribute to liver injury, neurodegeneration, and cancer.
• Cupric ion binding is a core molecular function for copper homeostasis and metal trafficking.
• It underlies the catalytic and structural roles of copper in enzymes and metalloproteins.
• Cu(2+) binding can modulate protein-lipid interactions, as shown for TRAAK-phosphatidylserine binding.
• Classic studies used cupric ion binding to characterize metal sites in serum albumin and ribonuclease.
• Copper-binding proteins can oxidize Cu(I) to Cu(II), linking cupric ion binding to redox cycling.
• Dysregulated copper metabolism and cuproptosis are implicated in acute liver injury.
• Cupric ion binding is relevant to designing metal-selective probes and protein-labeling reagents.
• It provides a framework for studying metal-protein interactions in nutrition and toxicology.
• Altered cupric ion binding may affect protein stability, aggregation, and function in disease.
• The term supports annotation and interpretation of copper-related omics and structural data.
Molecular Mechanism of cupric ion binding
Copper speciation and Cu(2+) availability
In simple terms: Copper can exist in two main forms, and this function is about the oxidized form, Cu(2+).
Cupric ion binding specifically involves copper in the Cu(2+) oxidation state, which is distinct from the reduced Cu(+) form. Experimental studies often use diligand metal-ion buffers to set and maintain free Cu(2+) concentrations, allowing quantitative analysis of binding to proteins such as bovine pancreatic ribonuclease. The redox state of copper is therefore a critical variable in defining this molecular function.
Metal-coordination sites in proteins
In simple terms: Proteins bind Cu(2+) through specific pockets made of amino acid side chains.
Cupric ion binding sites have been characterized in diverse proteins, including myoglobin derivatives and serum albumin, where distinct coordination environments determine affinity and selectivity. These sites typically involve nitrogen, oxygen, or sulfur ligands from amino acid side chains, and their geometry can be probed by spectroscopic and thermodynamic methods. The identity of the coordination site influences whether Cu(2+) binding is structural, catalytic, or regulatory.
Redox interconversion and multicopper proteins
In simple terms: Some proteins can change copper between its reduced and oxidized forms while binding it.
Multicopper proteins such as the green cupredoxin CopI can oxidize Cu(I) to Cu(II), directly linking cupric ion binding to redox chemistry. This interconversion is central to copper homeostasis and to the roles of copper in electron transfer and oxidative processes. Such proteins illustrate how cupric ion binding can be part of a dynamic redox cycle rather than a static interaction.
Modulation of protein-lipid and protein-protein interactions
In simple terms: Cu(2+) binding can change how a protein interacts with other molecules, including lipids.
Cupric ions can selectively modulate TRAAK-phosphatidylserine interactions, demonstrating that Cu(2+) binding can alter membrane association and protein-lipid recognition. This type of modulation expands the functional consequences of cupric ion binding beyond catalysis to include regulation of protein localization and complex formation. Such effects are relevant to signaling and membrane biology.
Chemical tools and selective labeling
In simple terms: Scientists use copper-sensitive reagents to detect and study Cu(2+) binding.
Protein-labeling reagents selectively activated by copper(I) have been developed, and these tools help dissect copper-dependent processes by distinguishing oxidation states. Although such reagents target Cu(I), they are often used alongside Cu(2+) binding assays to understand redox cycling and metal selectivity. These chemical approaches complement structural and biophysical methods for studying cupric ion binding.
Key Genes Involved in GO:1903135 cupric ion binding
The following genes and proteins are representative of cupric ion binding research, based on published biochemical and structural studies.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ALB | Serum albumin binds cupric ions at specific sites | Classic model for Cu(2+) binding and transport |
| MB | Myoglobin derivatives bind cupric ions | Early characterization of cupric ion binding sites |
| RNASE1 | Bovine pancreatic ribonuclease binds Cu(2+) | Used with diligand buffers to study metal binding |
| TRAAK | Potassium channel modulated by cupric ions | Cu(2+) selectively modulates lipid interactions |
| NRF2 | Transcription factor targeted by merestinib in cuproptosis | Links copper stress to acute liver injury |
| COPI | Multicopper protein that oxidizes Cu(I) | Model for redox interconversion and cupric ion binding |
| ATP7A | Copper-transporting ATPase | Copper homeostasis and Cu(2+) handling |
| ATP7B | Copper-transporting ATPase | Copper homeostasis and Cu(2+) handling |
| SLC31A1 | Copper importer | Controls intracellular copper availability |
| MT1A | Metallothionein binds copper | Metal sequestration and detoxification |
| MT2A | Metallothionein binds copper | Metal sequestration and detoxification |
| CP | Ceruloplasmin binds and oxidizes copper | Copper transport and redox chemistry |
| AOC1 | Copper amine oxidase | Copper-dependent catalysis |
| SOD1 | Cu/Zn superoxide dismutase | Copper binding in antioxidant defense |
| LOX | Lysyl oxidase | Copper-dependent enzyme in matrix biology |
| TYR | Tyrosinase | Copper-dependent enzyme in melanin synthesis |
| DBH | Dopamine beta-hydroxylase | Copper-dependent enzyme in catecholamine synthesis |
How Is cupric ion binding Regulated?
Cupric ion binding is regulated by copper availability, redox state, and metal chaperones that control Cu(2+) distribution. Multicopper proteins such as CopI can oxidize Cu(I) to Cu(II), thereby influencing the pool of cupric ions available for binding. In addition, copper-responsive transcription factors and stress pathways, including NRF2, modulate cellular responses to copper overload and cuproptosis. The interplay between copper import, sequestration, and oxidation therefore determines the extent and specificity of cupric ion binding in cells.
cupric ion binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NRF2 | Acute liver injury and cuproptosis | Knockout or overexpression in hepatocytes |
| TRAAK | Neuronal membrane signaling | Point mutation of Cu(2+)-sensitive residues |
| ATP7B | Copper metabolism disorders | Knock-in of disease-associated variants |
| SOD1 | Neurodegeneration and oxidative stress | Overexpression of mutant SOD1 |
| COPI | Copper redox homeostasis | Knockout in bacterial or fungal models |
Copper dysregulation and acute liver injury
Merestinib inhibits cuproptosis by targeting NRF2 to alleviate acute liver injury, indicating that copper-dependent stress pathways are relevant to liver disease. Cupric ion binding proteins contribute to copper handling, and their dysfunction can exacerbate oxidative damage.
Neurodegeneration and metal imbalance
Copper imbalance is associated with neurodegenerative conditions, and proteins that bind cupric ions are central to maintaining metal homeostasis in the nervous system. The modulation of TRAAK-phosphatidylserine interactions by cupric ions suggests that Cu(2+) can influence neuronal membrane signaling.
Cancer and redox signaling
Copper is required for enzymes involved in redox signaling and matrix remodeling, and altered copper metabolism can affect tumor progression. Cupric ion binding proteins such as SOD1 and LOX are relevant to oxidative stress and extracellular matrix dynamics in cancer.
From cupric ion binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does a candidate gene bind Cu(2+) directly? | Point mutation of predicted metal-coordinating residues |
| What is the effect of Cu(2+) binding on protein function? | Knockout with rescue by wild-type or binding-deficient mutant |
| How does Cu(2+) binding affect protein localization? | Tagged knock-in for imaging |
| Which genes mediate copper stress responses? | CRISPR library screening under Cu(2+) treatment |
| Does a disease variant alter cupric ion binding? | Knock-in of patient-derived mutations |
| Can overexpression of a copper-binding protein protect cells? | Overexpression cell models |
How to Study the cupric ion binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Isothermal titration calorimetry | Binding affinity and stoichiometry | Cu(2+) binding to purified proteins |
| EPR spectroscopy | Copper coordination and oxidation state | Characterizing Cu(2+) sites |
| X-ray crystallography | Three-dimensional structure of metal site | Defining coordination geometry |
| Fluorescence spectroscopy | Conformational changes upon binding | Protein-lipid interaction studies |
| CRISPR knockout screens | Genes required for copper stress response | Identifying copper homeostasis factors |
| Copper-activated labeling | Selective tagging of copper-binding proteins | Proteomic profiling |
| Cell viability assays | Cytotoxicity of Cu(2+) | Modeling cuproptosis and liver injury |
| Site-directed mutagenesis | Role of specific residues in binding | Validating metal-coordination sites |
Biophysical binding assays
Isothermal titration calorimetry, surface plasmon resonance, and fluorescence spectroscopy can measure Cu(2+) binding affinity and stoichiometry when free metal concentrations are controlled with diligand buffers. These methods are foundational for assigning GO:1903135 to a gene product.
Structural and spectroscopic characterization
X-ray crystallography, NMR, and electron paramagnetic resonance (EPR) can define the coordination geometry of cupric ion binding sites. Such data help distinguish Cu(2+) from Cu(+) binding and reveal redox-linked conformational changes.
Cell-based copper stress assays
Cellular assays using Cu(2+) treatment, viability readouts, and cuproptosis markers can link cupric ion binding to phenotypes such as acute liver injury. These experiments often combine CRISPR knockout or overexpression to test causality.
Proteomics and chemical labeling
Copper-activated protein-labeling reagents enable selective tagging of copper-binding proteins and can be coupled with mass spectrometry to identify targets. This approach complements classical binding studies and helps map redox-dependent interactions.
How CRISPR Can Be Used to Study GO:1903135 cupric ion binding
Knockout
CRISPR knockout of candidate cupric ion binding genes can test whether they are required for copper tolerance, redox homeostasis, or cuproptosis. Knockout models are particularly useful when combined with Cu(2+) treatment and phenotypic readouts such as viability or stress marker expression.
Point Mutation
Point mutations that alter predicted metal-coordinating residues can dissect the contribution of cupric ion binding to protein function. For example, mutating Cu(2+)-sensitive residues in TRAAK can reveal how binding modulates lipid interactions.
Knock-in
Knock-in of disease-associated variants or tagged alleles allows study of cupric ion binding in a physiological context. Tagged knock-in models enable imaging and proteomic analysis of copper-binding proteins without overexpression artifacts.
Overexpression
Overexpression of copper-binding proteins can test protective or toxic effects under copper stress. This approach is useful for validating gain-of-function mechanisms and for screening small-molecule modulators of cupric ion binding.
How EDITGENE Supports cupric ion binding Research
Researchers studying cupric ion binding-related genes often need to determine whether a candidate gene is causally involved in copper-dependent phenotypes, and CRISPR-based models provide a direct way to test this.
Contact EDITGENE today to design your custom CRISPR model for cupric ion binding research.
Frequently Asked Questions About cupric ion binding
What is cupric ion binding?
Cupric ion binding (GO:1903135) is the molecular function of binding to a cupric ion, copper(2+), as defined by the Gene Ontology.
What genes are involved in cupric ion binding?
Genes such as ALB, MB, RNASE1, TRAAK, NRF2, and COPI have been studied in the context of cupric ion binding.
How is cupric ion binding different from cuprous ion binding?
Cupric ion binding specifically involves Cu(2+), while cuprous ion binding involves Cu(+); the two are distinct oxidation states with different redox properties.
What methods are used to study cupric ion binding?
Common methods include isothermal titration calorimetry, EPR spectroscopy, X-ray crystallography, and diligand metal-ion buffers to control free Cu(2+).
Why is cupric ion binding important in disease?
Dysregulated copper metabolism and cuproptosis are linked to acute liver injury and other diseases, making cupric ion binding relevant to pathology.
Can CRISPR be used to study cupric ion binding?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models can test the function of cupric ion binding proteins.
What is the GO ID for cupric ion binding?
The GO ID for cupric ion binding is GO:1903135.
Which proteins bind cupric ions in serum?
Serum albumin is a classic cupric ion binding protein, and its Cu(2+) sites have been characterized biochemically.
How do multicopper proteins relate to cupric ion binding?
Multicopper proteins such as CopI can oxidize Cu(I) to Cu(II), directly connecting cupric ion binding to redox interconversion.
What is cuproptosis and how does it relate to cupric ion binding?
Cuproptosis is a copper-dependent cell death process, and cupric ion binding proteins contribute to copper handling and stress responses.
Conclusion
Cupric ion binding (GO:1903135) is a well-defined molecular function that captures the selective interaction of proteins with Cu(2+). It is experimentally tractable using metal-ion buffers, biophysical assays, and structural methods, and it is biologically important for copper homeostasis, redox chemistry, and disease. CRISPR-based models offer a powerful way to test the causal roles of cupric ion binding proteins in health and disease.
References
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- 2. Cheng R et al.. 2024. Protein-Labeling Reagents Selectively Activated by Copper(I).. ACS Chem Biol 19(6):1222-1228 PMID: 38747299
- 3. BRESLOW E. 1964. COMPARISON OF CUPRIC ION-BINDING SITES IN MYOGLOBIN DERIVATIVES AND SERUM ALBUMIN.. J Biol Chem 239:3252-9 PMID: 14245370
- 4. Saundry RH et al.. 1967. The binding of cupric ions to bovine pancreatic ribonuclease studies with diligand metal-ion buffers.. Biochem J 105(1):107-15 PMID: 6070125
- 5. Naik DV et al.. 1975. Binding of cupric ions to bovine serum albumin.. J Pharm Sci 64(7):1243-5 PMID: 1171218
- 6. Luo X et al.. 2025. Merestinib inhibits cuproptosis by targeting NRF2 to alleviate acute liver injury.. Free Radic Biol Med 229:68-81 PMID: 39824447
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- 8. Rossotti M et al.. 2024. The green cupredoxin CopI is a multicopper protein able to oxidize Cu(I).. J Inorg Biochem 254:112503 PMID: 38364337
