GO:0070026 nitric oxide binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0070026 nitric oxide binding is a molecular function defined as the binding of nitric oxide (NO), a gaseous signaling radical, to a protein or other biomolecule.
• NO binding is central to diverse physiological and pathological processes, including neurotransmission, vasodilation, immune defense, and mitochondrial regulation.
• Key NO-binding proteins include nitric oxide synthases (NOS1, NOS2, NOS3), soluble guanylate cyclase (GUCY1A2/GUCY1B3), cytochrome c oxidase, and CDGSH-type [2Fe-2S] cluster proteins such as CISD1 and CISD2.
• The binding of NO to heme and non-heme iron centers is a recurring theme, often forming nitrosyl complexes that modulate protein activity.
• Dysregulated NO binding contributes to neurodegeneration, tumor progression, and cardiovascular disease, making it a target for therapeutic intervention.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable precise dissection of NO-binding protein function in health and disease.
Description
Nitric oxide (NO) is a short-lived, gaseous free radical that acts as a signaling molecule in virtually all mammalian tissues. The molecular function of nitric oxide binding (GO:0070026) describes the selective interaction between NO and a target biomolecule, typically a metalloprotein or a heme-containing protein. This binding event is the first step in many NO-mediated signaling cascades, including activation of soluble guanylate cyclase, inhibition of cytochrome c oxidase, and modulation of iron-sulfur cluster proteins. Understanding nitric oxide binding is therefore fundamental to deciphering how NO exerts its pleiotropic effects in physiology and disease. Researchers study nitric oxide binding to uncover the structural and chemical basis of NO recognition, to identify new NO-binding proteins, and to develop drugs that modulate NO signaling. The interaction of NO with heme iron is one of the best-characterized binding modes, but non-heme iron centers and CDGSH-type [2Fe-2S] clusters also bind NO with high affinity. These interactions can lead to reversible or irreversible modifications, influencing protein stability, enzymatic activity, and cellular redox balance. Given the broad impact of NO in cancer, neurodegeneration, and cardiovascular disorders, precise experimental models are needed to dissect the causal roles of individual NO-binding proteins. This article integrates authoritative QuickGO annotation for GO:0070026 with verified PubMed literature to provide a research-grade overview of the term, its mechanisms, key genes, and methods for study.
nitric oxide binding At A Glance
| GO ID | GO:0070026 |
|---|---|
| GO term | nitric oxide binding |
| Ontology | molecular_function |
| Synonym | nitrogen monoxide binding; nitrosyl binding; NO binding |
| Major function | Binding to nitric oxide (NO), often via heme or non-heme iron centers, to modulate protein activity or signaling. |
| Common binding partners | Heme iron, [2Fe-2S] clusters, copper centers, and other metal cofactors. |
| Representative proteins | Nitric oxide synthases (NOS1, NOS2, NOS3), soluble guanylate cyclase (GUCY1A2/GUCY1B3), cytochrome c oxidase, CISD1, CISD2, horseradish peroxidase. |
| Associated diseases | Neurodegeneration, cancer, cardiovascular disorders, mitochondrial dysfunction. |
| Research methods | Spectrophotometry, EPR, crystallography, CRISPR knockout/knock-in, proteomics. |
What Is GO:0070026?
GO:0070026 nitric oxide binding is defined by QuickGO as the binding to nitric oxide (NO). In practical terms, it is the molecular function of a protein or other molecule to selectively interact with NO, often through a metal center such as heme iron or an iron-sulfur cluster. This binding can be reversible, as in NO binding to soluble guanylate cyclase, or can lead to stable nitrosyl adducts, as observed in some bacterial and mitochondrial proteins. The term is a child of binding (GO:0005488) and is distinct from nitric oxide synthase activity, which produces NO rather than binding it.
Why Is nitric oxide binding Important in Cell Biology?
Nitric oxide binding is a fundamental molecular event that underpins NO signaling in the nervous, cardiovascular, and immune systems. Because NO is a radical with a short half-life, its biological effects are largely determined by which proteins it binds and how those interactions alter protein function. Defects in NO binding contribute to diseases ranging from neurodegeneration to cancer, and pharmacological modulation of NO binding is a therapeutic strategy. Thus, understanding GO:0070026 is essential for both basic biology and translational research.
• NO binding to soluble guanylate cyclase mediates vasodilation and is targeted by drugs for cardiovascular disease.
• NO binding to cytochrome c oxidase can inhibit mitochondrial respiration and contribute to neurotoxicity.
• NO binding to CDGSH-type [2Fe-2S] clusters in Miner2 (CISD2) regulates mitochondrial iron and redox homeostasis.
• Aberrant NO binding is implicated in tumor progression and can be exploited for tumor therapy.
• NO binding to horseradish peroxidase serves as a model for understanding heme-NO interactions.
• Anammox bacteria use NO-binding cytochrome c complexes to drive hydrazine synthesis, highlighting evolutionary diversity.
• NO binding to iron-sulfur clusters can lead to cluster disassembly and altered protein function.
• The binding of NO to heme proteins is a paradigm for gasotransmitter signaling.
• CRISPR screens can identify genes required for NO binding and downstream signaling.
• NO binding is a key parameter in the development of NO-releasing therapeutics.
Molecular Mechanism of nitric oxide binding
Heme iron coordination
In simple terms: NO binds to the iron atom in heme, like a key fitting into a lock.
Many NO-binding proteins contain a heme prosthetic group, where the central iron atom provides a coordination site for NO. The binding of NO to ferrous or ferric heme can be reversible or lead to stable nitrosyl complexes, depending on the protein environment. For example, horseradish peroxidase binds NO via its heme iron, which can be monitored by absorption spectrometry. In soluble guanylate cyclase, NO binding to the heme iron triggers a conformational change that activates the enzyme, leading to cGMP production.
Non-heme iron-sulfur cluster binding
In simple terms: NO can also attach to iron-sulfur clusters, which are small iron-and-sulfur cages inside proteins.
CDGSH-type [2Fe-2S] clusters are found in mitochondrial proteins such as Miner2 (CISD2) and CISD1. These clusters can bind NO, forming nitrosyl adducts that may alter cluster stability and protein function. The binding of NO to these clusters is thought to be involved in mitochondrial iron handling and redox signaling. This mode of NO binding expands the repertoire of NO targets beyond heme proteins.
Copper and other metal centers
In simple terms: Some proteins use copper instead of iron to bind NO.
Copper-containing proteins, such as cytochrome c oxidase, can bind NO at their binuclear center, inhibiting oxygen reduction. The interaction of NO with copper centers is relevant to mitochondrial respiration and neurotoxicity. Other metal centers, including non-heme iron in enzymes like lipoxygenase, may also bind NO, though the physiological significance is less clear.
Regulation by redox state and cofactors
In simple terms: Whether NO binds often depends on the protein's oxidation state and the presence of helper molecules.
The redox state of the metal center dictates NO binding affinity and kinetics. For example, ferrous heme binds NO more tightly than ferric heme in many proteins. Cofactors such as tetrahydrobiopterin in nitric oxide synthases influence NO synthesis but also modulate NO binding to the enzyme's heme. Additionally, the local protein environment, including hydrogen bonding and steric constraints, fine-tunes NO binding specificity.
Bacterial NO-binding complexes
In simple terms: Even bacteria use NO binding for specialized chemistry.
In anammox bacteria, a nitric oxide-binding heterodimeric cytochrome c complex binds NO and interacts with hydrazine synthase, a key enzyme in the nitrogen cycle. This example illustrates that NO binding is not limited to eukaryotes and can serve unique metabolic roles. Studying such bacterial systems can provide insights into the fundamental chemistry of NO binding.
Key Genes Involved in GO:0070026 nitric oxide binding
The following genes encode proteins that directly bind nitric oxide or are intimately involved in NO binding-dependent processes, as supported by the verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NOS1 | Neuronal nitric oxide synthase; produces NO | NO synthesis and neurotoxicity |
| NOS2 | Inducible nitric oxide synthase; produces NO in immune response | Inflammation and tumor biology |
| NOS3 | Endothelial nitric oxide synthase; produces NO for vasodilation | Cardiovascular disease |
| GUCY1A2 | Soluble guanylate cyclase alpha subunit; binds NO via heme | NO signaling and vasodilation |
| GUCY1B3 | Soluble guanylate cyclase beta subunit; contains heme for NO binding | NO signaling and drug targets |
| CISD1 | Mitochondrial [2Fe-2S] protein; binds NO | Mitochondrial iron metabolism |
| CISD2 | Miner2; CDGSH-type [2Fe-2S] cluster; binds NO | Mitochondrial function and disease |
| COX1 | Cytochrome c oxidase subunit 1; binds NO at binuclear center | Mitochondrial respiration and neurotoxicity |
| COX2 | Cytochrome c oxidase subunit 2; part of NO binding site | Mitochondrial respiration |
| HPR | Horseradish peroxidase; model heme protein that binds NO | Heme-NO interaction studies |
| KUSTc1061 | Anammox cytochrome c; binds NO | Bacterial nitrogen cycle |
| HZS | Hydrazine synthase; interacts with NO-binding cytochrome c | Anammox metabolism |
| ALAS1 | Delta-aminolevulinate synthase; heme biosynthesis | Indirect role in NO binding via heme |
| FECH | Ferrochelatase; inserts iron into heme | Heme biosynthesis for NO-binding proteins |
| BLVRB | Biliverdin reductase B; heme degradation | Redox regulation of NO binding |
| NGB | Neuroglobin; heme protein that can bind NO | Neuroprotection |
| CYGB | Cytoglobin; heme protein with NO binding potential | Oxidative stress response |
How Is nitric oxide binding Regulated?
The binding of nitric oxide is regulated at multiple levels. The availability of NO itself is controlled by nitric oxide synthases (NOS1, NOS2, NOS3), which are regulated by calcium/calmodulin, phosphorylation, and transcriptional mechanisms. The redox state of target proteins, influenced by cellular antioxidants and reactive oxygen species, modulates NO binding affinity. Additionally, the expression levels of NO-binding proteins such as soluble guanylate cyclase and mitochondrial carriers are subject to transcriptional and post-translational regulation. In mitochondria, NO binding to cytochrome c oxidase is competitive with oxygen, linking NO signaling to metabolic state.
nitric oxide binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NOS1 | Neurodegeneration | Knockout mice, neuronal cell lines |
| NOS2 | Cancer, inflammation | Conditional knockout, tumor xenografts |
| NOS3 | Cardiovascular disease | Endothelial-specific knockout |
| CISD2 | Wolfram syndrome 2, mitochondrial disease | Knockout and knock-in cell models |
| GUCY1A2 | Hypertension, cardiovascular disease | Point mutation knock-in mice |
Neurodegeneration
Excessive nitric oxide production and subsequent binding to neuronal proteins contribute to neurotoxicity in conditions such as stroke, Parkinson's disease, and Alzheimer's disease. NO binding to cytochrome c oxidase inhibits mitochondrial respiration, leading to energy failure and neuronal death. Targeting NO binding may offer neuroprotective strategies.
Cancer
Nitric oxide binding to tumor suppressor proteins and DNA repair enzymes can promote or inhibit tumorigenesis depending on context. NO binding to iron-sulfur clusters in mitochondrial proteins like CISD2 may alter cancer cell metabolism. Therapeutic approaches that modulate NO binding are being explored for tumor therapy.
Cardiovascular disease
NO binding to soluble guanylate cyclase is essential for vasodilation, and impaired NO binding contributes to hypertension and heart failure. Drugs that enhance NO binding or mimic its effects, such as nitrates and sGC stimulators, are used clinically.
Mitochondrial disorders
Mutations in genes encoding NO-binding mitochondrial proteins, such as CISD2, cause Wolfram syndrome 2 and other mitochondrial diseases. Defective NO binding may exacerbate mitochondrial dysfunction and oxidative stress.
From nitric oxide binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of CISD2 affect NO binding to mitochondrial clusters? | CISD2 knockout cell line |
| How does a point mutation in the heme pocket of GUCY1A2 alter NO binding? | Point mutation knock-in |
| Can we tag endogenous NOS1 to track NO binding dynamics? | Tagged knock-in (e.g., GFP) |
| Does overexpression of NGB protect against NO-induced neurotoxicity? | Overexpression cell model |
| What genes are required for NO-dependent vasodilation? | CRISPR library screening |
| How does NO binding to cytochrome c oxidase affect respiration? | Knockout of COX1 in cell lines |
How to Study the nitric oxide binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| UV-Vis absorption spectrometry | Soret band shifts upon NO binding | Heme-NO interaction studies |
| EPR spectroscopy | Paramagnetic NO-metal complexes | Characterization of NO binding to iron-sulfur clusters |
| X-ray crystallography | Atomic structure of NO-bound protein | Structural basis of NO binding |
| CRISPR knockout screening | Genes required for NO binding or signaling | Discovery of novel NO-binding regulators |
| Proteomics | NO-modified proteins and binding partners | Global analysis of NO binding |
| Live-cell imaging | NO dynamics and protein localization | Real-time NO binding in cells |
| Site-directed mutagenesis | Effect of point mutations on NO binding | Validation of binding residues |
| Isothermal titration calorimetry | Binding affinity and thermodynamics | Quantitative NO binding studies |
Spectroscopic methods for NO binding
Absorption spectrometry, electron paramagnetic resonance (EPR), and resonance Raman spectroscopy are used to detect and characterize NO binding to heme and non-heme iron centers. These methods provide information on binding affinity, kinetics, and the oxidation state of the metal.
Structural biology
X-ray crystallography and cryo-electron microscopy can reveal the atomic details of NO binding sites in proteins. For example, the structure of the anammox cytochrome c complex with NO has provided insights into bacterial NO binding.
CRISPR-based genetic screens
Genome-wide CRISPR knockout or activation screens can identify genes that regulate NO binding and downstream signaling. Such screens are valuable for discovering novel NO-binding proteins or modifiers.
Proteomics and chemical biology
Activity-based probes and mass spectrometry can identify NO-modified cysteines and metal centers. These approaches enable global profiling of NO binding events in cells.
How CRISPR Can Be Used to Study GO:0070026 nitric oxide binding
Knockout
CRISPR knockout of genes encoding NO-binding proteins, such as CISD2 or GUCY1A2, allows researchers to assess the loss-of-function consequences on NO signaling and cellular phenotypes. Knockout cell lines can be used to measure changes in NO binding capacity, mitochondrial function, and downstream pathways.
Point Mutation
Introducing precise point mutations in the NO-binding pocket (e.g., heme-coordinating residues in GUCY1A2 or iron-sulfur cluster ligands in CISD2) via CRISPR base editing or homology-directed repair can dissect the contribution of specific residues to NO binding. Such models are invaluable for structure-function studies.
Knock-in
Knock-in of tagged versions of NO-binding proteins (e.g., GFP-NOS1 or HA-CISD2) enables real-time tracking of protein localization and interaction with NO. Knock-in of disease-associated mutations can model human disorders.
Overexpression
CRISPR activation (CRISPRa) or cDNA overexpression can increase levels of NO-binding proteins to study gain-of-function effects, such as protection against NO toxicity by neuroglobin. Overexpression models are useful for testing therapeutic hypotheses.
How EDITGENE Supports nitric oxide binding Research
Researchers studying nitric oxide binding-related genes often need to determine whether a candidate gene is causally involved in NO signaling, mitochondrial function, or disease. EDITGENE provides a comprehensive suite of CRISPR services to generate precisely engineered cell models, enabling rigorous functional validation of NO-binding proteins and their regulators.
Contact EDITGENE today to design your custom CRISPR model for nitric oxide binding research.
Frequently Asked Questions About nitric oxide binding
What is nitric oxide binding (GO:0070026)?
Nitric oxide binding is a molecular function defined as the binding to nitric oxide (NO), a gaseous signaling molecule. It often occurs through metal centers such as heme iron or iron-sulfur clusters.
What genes are involved in nitric oxide binding?
Key genes include NOS1, NOS2, NOS3 (which produce NO), GUCY1A2/GUCY1B3 (which bind NO), CISD1, CISD2, and cytochrome c oxidase subunits.
How does nitric oxide bind to proteins?
NO binds to transition metals, particularly iron in heme or [2Fe-2S] clusters, and to copper centers. The binding is often reversible and can modulate protein activity.
What diseases are associated with nitric oxide binding?
Dysregulated NO binding is linked to neurodegeneration, cancer, cardiovascular disease, and mitochondrial disorders.
What methods are used to study nitric oxide binding?
Common methods include UV-Vis absorption spectrometry, EPR, X-ray crystallography, CRISPR screens, and proteomics.
Can CRISPR be used to study nitric oxide binding?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models allow precise dissection of NO-binding protein function.
What is the role of CISD2 in nitric oxide binding?
CISD2 (Miner2) contains a CDGSH-type [2Fe-2S] cluster that can bind NO, influencing mitochondrial iron and redox homeostasis.
How does nitric oxide binding affect mitochondrial function?
NO binding to cytochrome c oxidase inhibits respiration, while binding to iron-sulfur clusters can disrupt mitochondrial iron metabolism.
Is nitric oxide binding reversible?
Many NO binding events are reversible, but some can form stable nitrosyl adducts, depending on the protein and redox state.
What is the therapeutic potential of targeting nitric oxide binding?
Modulating NO binding is explored for cardiovascular diseases, cancer, and neurodegeneration, with drugs like sGC stimulators already in use.
Conclusion
Nitric oxide binding (GO:0070026) is a fundamental molecular function that mediates the diverse biological actions of NO. From heme proteins to iron-sulfur clusters, the binding of NO to metal centers regulates key physiological processes and contributes to disease when dysregulated. Understanding the structural and chemical basis of NO binding is essential for developing targeted therapies. CRISPR-based models provide powerful tools to dissect the causal roles of NO-binding proteins in health and disease. EDITGENE offers a full range of CRISPR services to support this research, from knockout to knock-in and library screening, enabling precise and reproducible experiments.
References
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