GO:0003910 DNA ligase (ATP) activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0003910 DNA ligase (ATP) activity catalyzes the ATP-dependent joining of a 5'-phosphate to a 3'-hydroxyl at a DNA nick, releasing AMP and diphosphate.
• Mammalian cells express multiple ATP-dependent DNA ligases, including LIG1, LIG3, and LIG4, which act in replication, base excision repair, and non-homologous end joining, respectively.
• Altered DNA ligase activity is directly linked to human disease, including immunodeficiency, cancer predisposition, and neurodegeneration.
• DNA ligase (ATP) activity is essential for CRISPR-Cas9-mediated precise gene editing, especially for homology-directed repair and knock-in strategies.
• Non-homologous end joining relies on coordinated assembly and ligation steps that can be studied with dynamic imaging and biochemical reconstitution.
• Extrachromosomal DNA maintenance and apoptotic DNA fragmentation involve ATP-dependent ligation and repair pathways relevant to cancer and immunity.
Description
DNA ligase (ATP) activity (GO:0003910) is a molecular function that seals breaks in the DNA backbone by forming a phosphodiester bond between adjacent nucleotides, using ATP as the energy source. This activity is fundamental to DNA replication, repair, and recombination, and it is conserved across all domains of life. In eukaryotic cells, multiple ATP-dependent DNA ligases carry out specialized roles: LIG1 functions in DNA replication and excision repair, LIG3 is involved in base excision repair and mitochondrial DNA maintenance, and LIG4 is the primary ligase for non-homologous end joining. The reaction catalyzed by these enzymes is essential for maintaining genome integrity and for completing DNA transactions that involve nicks or double-strand breaks. Researchers study GO:0003910 to understand how cells preserve genetic information, how defects in ligation lead to disease, and how to optimize genome editing outcomes. Because DNA ligase (ATP) activity is central to many DNA repair pathways, it is also a target for therapeutic intervention in cancer and a key consideration in CRISPR-based experimental design.
DNA ligase (ATP) activity At A Glance
| GO ID | GO:0003910 |
|---|---|
| GO term | DNA ligase (ATP) activity |
| Ontology | molecular_function |
| Synonym | DNA joinase; DNA-joining enzyme; polynucleotide ligase (ATP); sealase |
| Major function | ATP-dependent sealing of nicks in double-stranded DNA by forming a phosphodiester bond |
| Reaction | ATP + deoxyribonucleotide(n) + deoxyribonucleotide(m) = AMP + diphosphate + deoxyribonucleotide(n+m) |
| Cofactor | ATP (required); Mg2+ (typical for many ligases) |
| Subcellular location | Nucleus (LIG1, LIG4), mitochondria (LIG3), and other compartments depending on isoform |
| Representative genes | LIG1, LIG3, LIG4 (mammalian); LIGA, LIGB, LIGC, LIGD (bacteria) |
What Is GO:0003910?
GO:0003910 DNA ligase (ATP) activity is defined as the catalysis of the reaction: ATP + deoxyribonucleotide(n) + deoxyribonucleotide(m) = AMP + diphosphate + deoxyribonucleotide(n+m). In other words, it is the ATP-dependent joining of two DNA strands by forming a phosphodiester bond, with the concomitant hydrolysis of ATP to AMP and diphosphate. This activity is also known by synonyms such as DNA joinase, DNA-joining enzyme, and polynucleotide ligase (ATP).
Why Is DNA ligase (ATP) activity Important in Cell Biology?
DNA ligase (ATP) activity is indispensable for genome maintenance because it completes the final step of many DNA repair and replication pathways, without which cells accumulate strand breaks and mutations. Defects in ATP-dependent DNA ligases cause a spectrum of human diseases, including immunodeficiency, radiosensitivity, and cancer predisposition. In biotechnology, DNA ligase (ATP) activity is exploited for molecular cloning, next-generation sequencing library preparation, and CRISPR-Cas9-mediated knock-in strategies. Therefore, understanding its mechanism, regulation, and roles in disease is critical for both basic research and therapeutic development.
• Essential for DNA replication: LIG1 seals Okazaki fragments during lagging-strand synthesis.
• Central to base excision repair: LIG3 and LIG1 complete repair of damaged bases.
• Required for non-homologous end joining: LIG4 ligates double-strand breaks.
• Maintains mitochondrial DNA integrity: LIG3 is the primary ligase in mitochondria.
• Mutations in LIG1 cause immunodeficiency and growth retardation.
• LIG4 mutations lead to LIG4 syndrome, characterized by radiosensitivity and immune deficiency.
• Altered ligase activity is observed in various cancers, making it a potential therapeutic target.
• DNA ligase (ATP) activity is critical for CRISPR-Cas9 homology-directed repair and precise gene knock-in.
• Apoptotic DNA fragmentation and extrachromosomal DNA formation involve ligation and repair pathways.
• Enzymatic DNA assembly methods rely on ATP-dependent ligases for synthetic biology.
Mechanism, Genes and Research Methods
What Happens During DNA ligase (ATP) activity?
In simple terms: DNA ligase acts like a molecular glue that seals breaks in the DNA strand using energy from ATP.
The catalytic cycle of ATP-dependent DNA ligases proceeds in three steps: (1) adenylation of the enzyme by ATP, releasing diphosphate and forming a covalent enzyme-AMP intermediate; (2) transfer of AMP to the 5'-phosphate of the DNA nick, activating it; and (3) nucleophilic attack by the 3'-hydroxyl on the activated 5'-phosphate, forming a phosphodiester bond and releasing AMP. This mechanism is conserved among eukaryotic and bacterial ATP-dependent ligases.
Substrate recognition and nick sealing
In simple terms: The enzyme finds a broken DNA strand and joins the two ends together.
DNA ligases recognize nicks or gaps with a 5'-phosphate and a 3'-hydroxyl. The enzyme binds to the DNA, distorting the helix to bring the ends into proximity. For LIG1, interaction with proliferating cell nuclear antigen (PCNA) targets it to replication and repair sites. LIG4 forms a complex with XRCC4 and XLF to bridge and ligate double-strand breaks during non-homologous end joining.
Cellular roles and pathway integration
In simple terms: Different ligases work in different DNA repair and replication jobs.
LIG1 is essential for DNA replication and excision repair; LIG3 functions in base excision repair and mitochondrial DNA maintenance; LIG4 is dedicated to non-homologous end joining. These enzymes are integrated into larger repair complexes, such as the XRCC1-LIG3 complex in base excision repair, which prevents toxic PARP1 trapping. Dynamic assembly of non-homologous end joining factors ensures coordinated ligation.
Molecular mechanism and cofactors
In simple terms: ATP provides the energy, and magnesium helps the reaction.
ATP is required for the formation of the enzyme-AMP intermediate. Mg2+ is typically required for catalysis, stabilizing the transition state. The reaction produces AMP and diphosphate as byproducts. The catalytic domain contains conserved motifs, including the KxDG motif that forms the lysine-AMP adduct.
Regulation of DNA ligase (ATP) activity
In simple terms: Cells control when and where ligases are active to avoid mistakes.
DNA ligase activity is regulated at multiple levels: transcription, post-translational modifications (phosphorylation, ubiquitination, SUMOylation), and protein-protein interactions. For example, LIG1 is phosphorylated by CDKs during the cell cycle, and its interaction with PCNA is regulated. LIG4 activity is modulated by its partners XRCC4 and XLF, and by ATM-mediated phosphorylation in response to DNA damage. Altered regulation can lead to disease.
Key Genes Involved in GO:0003910 DNA ligase (ATP) activity
The following genes encode proteins that possess or directly support ATP-dependent DNA ligase activity in humans and model organisms.
| Gene | Major Role | Research Relevance |
|---|---|---|
| LIG1 | ATP-dependent DNA ligase I; seals nicks during replication and excision repair | Immunodeficiency, cancer, CRISPR knock-in optimization |
| LIG3 | ATP-dependent DNA ligase III; base excision repair and mitochondrial DNA maintenance | Neurodegeneration, cancer, PARP inhibitor response |
| LIG4 | ATP-dependent DNA ligase IV; non-homologous end joining | LIG4 syndrome, radiosensitivity, immunodeficiency |
| XRCC1 | Scaffold protein that recruits LIG3 to base excision repair sites | Base excision repair, PARP1 trapping, cancer therapy |
| XRCC4 | Cofactor for LIG4 in non-homologous end joining | DNA repair, cancer predisposition |
| NHEJ1 (XLF) | Stimulates LIG4 activity and aligns DNA ends | Immunodeficiency, radiosensitivity |
| PCNA | Clamp that targets LIG1 to replication and repair sites | Replication, DNA repair, cell cycle |
| APTX | Aprataxin; removes AMP from 5'-phosphate after abortive ligation | Neurodegeneration (ataxia-oculomotor apraxia) |
| PARP1 | Poly(ADP-ribose) polymerase; recruits repair factors including LIG3 | Base excision repair, cancer therapy |
| FEN1 | Flap endonuclease; processes DNA ends before ligation | Replication and repair |
| POLB | DNA polymerase beta; fills gaps in base excision repair before ligation | Base excision repair, cancer |
| RAD51 | Homologous recombination; facilitates HDR for CRISPR knock-in | Precise gene editing |
| BRCA1 | Homologous recombination; influences repair pathway choice | Cancer, CRISPR HDR efficiency |
| TP53BP1 | Promotes non-homologous end joining over HDR | DNA repair pathway choice, CRISPR editing |
| LIGA (bacteria) | NAD+-dependent DNA ligase in bacteria (not ATP-dependent) | Antibacterial target; not GO:0003910 |
| LIGD (bacteria) | ATP-dependent DNA ligase D in Mycobacterium | Bacterial DNA repair, potential drug target |
How Is DNA ligase (ATP) activity Regulated?
DNA ligase (ATP) activity is regulated by cell cycle-dependent expression, post-translational modifications, and interaction with accessory proteins. LIG1 is phosphorylated by cyclin-dependent kinases, which modulates its activity and localization during S phase. LIG3 is stabilized by XRCC1, and their interaction is critical for base excision repair; disruption leads to PARP1 trapping and cell death. LIG4 activity depends on its association with XRCC4 and XLF, and is regulated by ATM-mediated phosphorylation in response to DNA damage. Additionally, oxidative stress and apoptotic signaling can influence ligase activity, as seen in extrachromosomal DNA formation and apoptotic DNA fragmentation.
DNA ligase (ATP) activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| LIG1 | Immunodeficiency, growth retardation, radiosensitivity | LIG1 knockout cell lines, patient-derived iPSCs |
| LIG3 | Neurodegeneration, mitochondrial dysfunction, cancer | LIG3 conditional knockout mice, neuronal cell models |
| LIG4 | LIG4 syndrome, severe combined immunodeficiency | LIG4 knockout mice, patient fibroblasts |
| APTX | Ataxia-oculomotor apraxia 1 | APTX knockout neurons, iPSC-derived models |
| XRCC1 | Base excision repair defects, cancer predisposition | XRCC1 knockout cells, PARP inhibitor sensitivity assays |
Immunodeficiency and radiosensitivity
Mutations in LIG1 cause a rare immunodeficiency with growth retardation and radiosensitivity, highlighting the non-redundant role of DNA ligase I in humans. LIG4 mutations lead to LIG4 syndrome, characterized by severe combined immunodeficiency, radiosensitivity, and developmental defects. These disorders underscore the importance of ATP-dependent ligation in immune cell development and DNA damage response.
Cancer and genome instability
Altered DNA ligase activity contributes to genome instability and cancer. Overexpression of LIG1 and LIG3 has been observed in various cancers, and their inhibition sensitizes cancer cells to DNA-damaging agents. LIG3 is also involved in extrachromosomal DNA maintenance in tumors, which can promote oncogene amplification. Targeting ATP-dependent ligases is a potential therapeutic strategy.
Neurodegeneration
Defects in DNA ligase III and associated repair factors are linked to neurodegeneration. For example, mutations in APTX, which resolves abortive ligation intermediates, cause ataxia-oculomotor apraxia 1. LIG3 deficiency in the brain leads to mitochondrial dysfunction and neuronal loss in model organisms. These findings connect ATP-dependent DNA ligation to neuronal survival.
Apoptosis and immune signaling
During apoptosis, DNA fragmentation produces extrachromosomal DNA circles that can stimulate innate immune responses. ATP-dependent ligases participate in the formation and maintenance of these eccDNAs, linking DNA ligation to inflammation and autoimmunity. This emerging area highlights the broader biological impact of DNA ligase (ATP) activity beyond genome maintenance.
From DNA ligase (ATP) activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of LIG1 affect replication and repair? | LIG1 knockout cell lines (e.g., HAP1, HEK293T) |
| How do point mutations in LIG4 affect non-homologous end joining? | LIG4 point-mutant knock-in cells |
| Can LIG3 be targeted to mitochondria specifically? | LIG3 isoform-specific knockout or tagged knock-in |
| What is the role of LIG1 in CRISPR HDR? | LIG1 overexpression or knockout in CRISPR-edited cells |
| How does XRCC1-LIG3 interaction prevent PARP1 trapping? | XRCC1 knockout and LIG3 knockout cells |
| Does LIG4 syndrome mutation affect ligase activity? | Patient-derived iPSCs with LIG4 mutation knock-in |
How to Study the DNA ligase (ATP) activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| In vitro ligation assay | Enzymatic joining of DNA strands | Kinetic analysis of LIG1, LIG3, LIG4 |
| Comet assay | DNA strand breaks in cells | Assessing repair capacity after damage |
| gamma-H2AX foci | Double-strand break repair | Evaluating NHEJ efficiency in LIG4 mutants |
| CRISPR HDR reporter | Homology-directed repair efficiency | Optimizing knock-in with ligase modulators |
| Co-immunoprecipitation | Protein-protein interactions | Mapping LIG3-XRCC1, LIG4-XRCC4 complexes |
| Cryo-EM | 3D structure of ligase-DNA complexes | Understanding catalytic mechanism |
| RNA-seq | Gene expression changes | Measuring ligase expression in disease models |
| Proteomics | Post-translational modifications | Identifying regulatory phosphorylation of LIG1 |
Biochemical ligation assays
In vitro ligation assays using purified enzymes and synthetic DNA substrates with a nick or gap measure the catalytic activity of DNA ligase (ATP) directly. These assays typically monitor the conversion of a labeled substrate to a ligated product by gel electrophoresis. They are used to determine kinetic parameters, cofactor requirements, and inhibitor effects.
Cell-based DNA repair assays
Comet assays, gamma-H2AX foci staining, and plasmid-based repair assays measure the cellular capacity to repair DNA breaks, indirectly reflecting DNA ligase activity. For example, the persistence of gamma-H2AX foci after irradiation indicates defective non-homologous end joining in LIG4-deficient cells. These assays are often combined with knockout or knockdown of specific ligases.
CRISPR-based editing readouts
To study the role of DNA ligase (ATP) activity in genome editing, researchers use CRISPR-Cas9 to introduce double-strand breaks and then measure HDR efficiency with fluorescent reporters or sequencing. Knockout of LIG4 or overexpression of LIG1 can shift repair outcomes. These experiments help optimize knock-in strategies.
Structural and interaction studies
X-ray crystallography, cryo-EM, and co-immunoprecipitation reveal how DNA ligases bind DNA and interact with partners. For example, structures of LIG4-XRCC4-XLF complexes have elucidated the architecture of non-homologous end joining. These methods provide mechanistic insights into ligation.
How CRISPR Can Be Used to Study GO:0003910 DNA ligase (ATP) activity
Knockout
CRISPR-Cas9 knockout of LIG1, LIG3, or LIG4 is used to study their essential roles in DNA repair and replication. For example, LIG4 knockout cells are hypersensitive to ionizing radiation and defective in non-homologous end joining. These models help dissect pathway-specific functions and identify synthetic lethal interactions.
Point Mutation
Point mutations in ligase genes, such as those found in LIG1-deficient patients, can be introduced by CRISPR-Cas9 with homology-directed repair to model disease-associated alleles. These knock-in models allow precise structure-function studies and drug testing.
Knock-in
Knock-in of tags (e.g., GFP, FLAG) into endogenous LIG1, LIG3, or LIG4 loci enables live-cell imaging and proteomic analysis of ligase complexes. CRISPR-mediated knock-in of reporter cassettes also allows quantification of HDR efficiency.
Overexpression
Overexpression of DNA ligases via CRISPR activation or lentiviral delivery can enhance HDR and knock-in efficiency in cell models. Conversely, overexpression of dominant-negative ligase mutants can inhibit specific repair pathways.
How EDITGENE Supports DNA ligase (ATP) activity Research
Researchers studying DNA ligase (ATP) activity-related genes often need to determine whether a candidate gene is causally involved in DNA repair, replication, or disease. EDITGENE provides comprehensive CRISPR-based services to create precisely engineered cell models, enabling functional validation of ligase genes and their partners.
Contact EDITGENE today to design your custom CRISPR model for DNA ligase (ATP) activity research.
Frequently Asked Questions About DNA ligase (ATP) activity
What is DNA ligase (ATP) activity?
DNA ligase (ATP) activity (GO:0003910) is the ATP-dependent catalysis of joining two DNA strands by forming a phosphodiester bond, releasing AMP and diphosphate.
What genes are involved in DNA ligase (ATP) activity?
Key genes include LIG1, LIG3, and LIG4 in humans, as well as bacterial ligases such as LIGD.
What is the difference between ATP-dependent and NAD+-dependent DNA ligases?
ATP-dependent ligases use ATP as a cofactor and are found in eukaryotes and some bacteria, while NAD+-dependent ligases use NAD+ and are primarily bacterial.
How is DNA ligase (ATP) activity measured?
It is measured using in vitro ligation assays with synthetic DNA substrates, or indirectly by cellular DNA repair assays such as comet assay and gamma-H2AX foci.
What diseases are associated with DNA ligase (ATP) activity?
Mutations in LIG1 cause immunodeficiency, LIG4 mutations cause LIG4 syndrome, and LIG3 defects are linked to neurodegeneration and cancer.
Can CRISPR-Cas9 knock out DNA ligase genes?
Yes, CRISPR-Cas9 can efficiently knock out LIG1, LIG3, or LIG4 in cell lines, enabling functional studies.
How does DNA ligase (ATP) activity affect CRISPR knock-in efficiency?
LIG4-mediated non-homologous end joining competes with HDR; inhibiting LIG4 or enhancing LIG1 can improve knock-in efficiency.
What are the synonyms for DNA ligase (ATP) activity?
Synonyms include DNA joinase, DNA-joining enzyme, polynucleotide ligase (ATP), and sealase.
Which ligase is responsible for mitochondrial DNA repair?
LIG3 is the primary DNA ligase in mitochondria and is essential for mitochondrial DNA maintenance.
How can I study DNA ligase (ATP) activity in my lab?
You can use biochemical assays, knockout cell lines, and CRISPR-based editing readouts; EDITGENE offers custom services for these approaches.
Conclusion
DNA ligase (ATP) activity (GO:0003910) is a fundamental molecular function that seals DNA breaks and is essential for replication, repair, and recombination. Its dysregulation causes immunodeficiency, cancer, and neurodegeneration, making it a critical research and therapeutic target. Advances in CRISPR-based models and biochemical assays continue to illuminate the mechanisms and regulation of ATP-dependent ligases. EDITGENE provides comprehensive tools to study these processes and accelerate discoveries in DNA repair biology.
References
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- 3. Gibson DG. 2011. Enzymatic assembly of overlapping DNA fragments.. Methods Enzymol 498:349-61 PMID: 21601685
- 4. Demin AA et al.. 2021. XRCC1 prevents toxic PARP1 trapping during DNA base excision repair.. Mol Cell 81(14):3018-3030.e5 PMID: 34102106
- 5. Wang Y et al.. 2021. eccDNAs are apoptotic products with high innate immunostimulatory activity.. Nature 599(7884):308-314 PMID: 34671165
- 6. Liu L et al.. 2025. Dynamic assemblies and coordinated reactions of non-homologous end joining.. Nature 643(8072):847-854 PMID: 40500445
- 7. Chu VT et al.. 2015. Increasing the efficiency of homology-directed repair for CRISPR-Cas9-induced precise gene editing in mammalian cells.. Nat Biotechnol 33(5):543-8 PMID: 25803306
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