GO:0004824 lysine-tRNA ligase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004824 (lysine-tRNA ligase activity) catalyzes the attachment of L-lysine to tRNA(Lys), a critical step in protein synthesis.
• The enzyme, lysyl-tRNA synthetase (KARS1), is highly conserved and essential across all domains of life.
• Mutations in KARS1 are linked to human diseases including ovarian insufficiency and neurological disorders.
• Lysyl-tRNA synthetase is a validated drug target in malaria parasites, with inhibitors like cladosporin showing potent antimalarial activity.
• Post-translational modifications, such as acetylation, regulate aminoacyl-tRNA synthetase activity in bacteria.
• Advanced CRISPR models (knockout, point mutation, knock-in, overexpression) enable precise functional dissection of KARS1 in health and disease.
Description
Lysine-tRNA ligase activity (GO:0004824) is a fundamental molecular function that ensures the accurate translation of the genetic code by attaching the amino acid L-lysine to its cognate transfer RNA (tRNA(Lys)). This reaction, catalyzed by lysyl-tRNA synthetase (KARS1), is essential for protein biosynthesis and cell viability across all kingdoms of life. Beyond its canonical role, KARS1 has been implicated in diverse cellular processes, including immune signaling and disease pathogenesis. Understanding the molecular mechanism, regulation, and disease relevance of lysine-tRNA ligase activity is therefore of broad interest to researchers in genetics, biochemistry, and drug discovery.
lysine-tRNA ligase activity At A Glance
| GO ID | GO:0004824 |
|---|---|
| GO term | lysine-tRNA ligase activity |
| Ontology | molecular_function |
| Synonym | L-lysine-transfer RNA ligase activity; lysyl-tRNA synthetase activity; lysine translase activity |
| Major function | Catalyzes the attachment of L-lysine to tRNA(Lys) for protein synthesis |
| Reaction | ATP + L-lysine + tRNA(Lys) = AMP + diphosphate + L-lysyl-tRNA(Lys) |
| Cofactors | ATP, Mg2+ |
| Localization | Cytoplasm (and mitochondria for mitochondrial isoform) |
| EC number | 6.1.1.6 |
What Is GO:0004824?
GO:0004824 describes the catalytic activity of an enzyme that joins L-lysine to its corresponding tRNA molecule using ATP. Specifically, it catalyzes the reaction: ATP + L-lysine + tRNA(Lys) = AMP + diphosphate + L-lysyl-tRNA(Lys). This activity is also known as lysyl-tRNA synthetase activity and is essential for incorporating lysine into nascent polypeptide chains during translation.
Why Is lysine-tRNA ligase activity Important in Cell Biology?
Lysine-tRNA ligase activity is indispensable for translation and thus for cell growth and proliferation. Its dysfunction leads to severe human diseases, including ovarian insufficiency and neurological disorders. Moreover, because of its essential role, it is a target for antimicrobial and antiparasitic drugs, such as inhibitors against Plasmodium lysyl-tRNA synthetase. Studying this activity provides insights into fundamental biology and therapeutic development.
• Essential for protein synthesis and cell viability.
• Mutations in KARS1 cause ovarian insufficiency and other developmental defects.
• Target for antimalarial drugs like cladosporin and novel inhibitors.
• Regulated by post-translational modifications such as acetylation.
• Involved in immune response and cytokine production.
• Potential role in cancer through moonlighting functions.
• Key enzyme for genetic code fidelity.
• Model for studying aminoacyl-tRNA synthetase evolution.
• Basis for developing antibiotics and antiparasitics.
• Important for understanding mitochondrial translation.
What Happens During lysine-tRNA ligase activity?
Substrate Binding and Activation
In simple terms: The enzyme grabs lysine and ATP to prepare for tRNA charging.
Lysyl-tRNA synthetase binds L-lysine and ATP in its active site, forming a lysyl-adenylate intermediate with the release of pyrophosphate. This step requires Mg2+ as a cofactor.
tRNA Recognition and Aminoacylation
In simple terms: The enzyme finds the correct tRNA and attaches lysine to it.
The enzyme specifically recognizes tRNA(Lys) through identity elements in the acceptor stem and anticodon loop. The lysyl group is then transferred to the 3'-OH of the terminal adenosine of tRNA(Lys), forming lysyl-tRNA(Lys).
Proofreading and Editing
In simple terms: The enzyme double-checks to avoid attaching the wrong amino acid.
Some lysyl-tRNA synthetases possess editing activity to hydrolyze mischarged tRNA, ensuring translational fidelity. This proofreading is crucial for cellular accuracy.
Release of Products
In simple terms: The charged tRNA is released to deliver lysine to the ribosome.
After aminoacylation, lysyl-tRNA(Lys) is released from the enzyme and binds to elongation factor Tu for delivery to the ribosome during protein synthesis.
Key Genes Involved in GO:0004824 lysine-tRNA ligase activity
The primary gene encoding lysine-tRNA ligase activity is KARS1, but other genes and proteins modulate its function and are relevant to research.
| Gene | Major Role | Research Relevance |
|---|---|---|
| KARS1 | Encodes lysyl-tRNA synthetase, catalyzing lysine-tRNA charging | Mutations linked to ovarian insufficiency and neurological disorders |
| AARS1 | Alanyl-tRNA synthetase, can moonlight as lactyltransferase | Implicated in tumorigenesis via p53 lactylation |
| AARS1 | Alanyl-tRNA synthetase, promotes YAP signaling | Role in gastric cancer |
| KARS1 | Mitochondrial lysyl-tRNA synthetase isoform | Essential for mitochondrial translation |
| KARS1 | Target of antimalarial inhibitors | Plasmodium lysyl-tRNA synthetase as drug target |
| KARS1 | Inhibited by cladosporin | Antimalarial drug development |
| KARS1 | Inhibited by lysine analogs | Collagen biosynthesis inhibition |
| KARS1 | Regulated by acetylation | Post-translational control in E. coli |
| KARS1 | Moonlighting in cytokine production | Immune response |
| KARS1 | Involved in tRNA channeling | Protein synthesis efficiency |
| KARS1 | Subject to alternative splicing | Tissue-specific functions |
| KARS1 | Interacts with other synthetases | Multi-synthetase complex |
| KARS1 | Phosphorylation sites | Regulation by kinases |
| KARS1 | Autoantibody target | Autoimmune diseases |
| KARS1 | Evolutionarily conserved | Model for enzyme evolution |
| KARS1 | Potential cancer target | Proliferation dependency |
| KARS1 | Role in angiogenesis | Endothelial cell function |
How Is lysine-tRNA ligase activity Regulated?
Lysine-tRNA ligase activity is regulated at multiple levels. In Escherichia coli, acetylation of lysine residues on aminoacyl-tRNA synthetases modulates their activity. In humans, KARS1 is subject to alternative splicing, post-translational modifications, and interaction with other proteins in the multi-synthetase complex. Additionally, its expression can be induced by immune stimuli, linking it to inflammatory responses.
lysine-tRNA ligase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| KARS1 | Ovarian insufficiency | Knockout mouse or patient-derived iPSCs |
| KARS1 | Malaria | Plasmodium falciparum culture with inhibitors |
| AARS1 | Gastric cancer | Knockout or overexpression in gastric cancer cell lines |
| AARS1 | Tumorigenesis via p53 lactylation | Point mutation knock-in of lactylation sites |
| KARS1 | Autoimmune myositis | Overexpression in cell models to study autoantibody targets |
Ovarian Insufficiency and Developmental Disorders
Mutations in KARS1 have been identified in patients with ovarian insufficiency, highlighting its role in gonadal development and function. These mutations often impair tRNA charging, leading to cellular stress and apoptosis in sensitive tissues.
Malaria and Infectious Diseases
Plasmodium lysyl-tRNA synthetase is a promising target for antimalarial drugs. Inhibitors such as cladosporin and optimized derivatives show potent multistage activity against malaria parasites.
Cancer and Metabolic Reprogramming
Aminoacyl-tRNA synthetases, including KARS1, are implicated in cancer. For example, AARS1 acts as a lactate sensor and lactyltransferase, modifying p53 and promoting tumorigenesis. AARS1 also promotes YAP signaling in gastric cancer, suggesting broader roles for synthetases in oncogenic pathways.
Neurological and Autoimmune Conditions
KARS1 mutations have been associated with neurological phenotypes, and autoantibodies against lysyl-tRNA synthetase are found in autoimmune diseases such as polymyositis.
From lysine-tRNA ligase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the effect of KARS1 loss on cell viability? | CRISPR knockout in HeLa or HEK293T cells |
| How do disease-associated KARS1 mutations affect tRNA charging? | Point mutation knock-in in isogenic cell lines |
| Can KARS1 be targeted for antimalarial therapy? | Plasmodium falciparum knockout or inhibitor assays |
| What is the role of KARS1 acetylation? | Knock-in of acetylation-mimetic or -dead mutants |
| Does KARS1 overexpression drive proliferation? | Overexpression in cancer cell lines |
| How does KARS1 interact with other synthetases? | Tagged knock-in for affinity purification |
How to Study the lysine-tRNA ligase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Aminoacylation assay | Enzyme activity | Kinetic characterization and inhibitor screening |
| CRISPR knockout screen | Gene essentiality and synthetic lethality | Identify modifiers of KARS1 function |
| X-ray crystallography | 3D structure of enzyme-inhibitor complex | Structure-guided drug design |
| RNA-seq | Transcriptional changes | Assess cellular response to KARS1 loss |
| Proteomics | Protein expression and modifications | Identify acetylation or lactylation targets |
| Ribo-seq | Translation efficiency | Measure impact on global protein synthesis |
| Immunofluorescence | Subcellular localization | Study KARS1 trafficking and complex formation |
Biochemical Assays for tRNA Charging
In vitro aminoacylation assays using purified KARS1 and tRNA(Lys) measure the formation of lysyl-tRNA(Lys) by acid precipitation or fluorescence. These assays are fundamental to characterize enzyme kinetics and inhibitor efficacy.
CRISPR-Based Genetic Screens
Genome-wide CRISPR knockout screens can identify genes that modulate sensitivity to KARS1 inhibitors or that synthetic-lethal with KARS1 loss, revealing pathways and potential drug targets.
Structural Biology and Molecular Docking
X-ray crystallography and cryo-EM structures of KARS1 with substrates or inhibitors guide the design of new drugs, as demonstrated for Plasmodium KARS1 inhibitors.
Omics Approaches
RNA-seq and proteomics can assess global changes in gene expression and protein abundance upon KARS1 perturbation, uncovering moonlighting functions and cellular stress responses.
How CRISPR Can Be Used to Study GO:0004824 lysine-tRNA ligase activity
Knockout
CRISPR knockout of KARS1 in cell lines abolishes lysine-tRNA ligase activity, leading to translation arrest and cell death, confirming its essentiality. Conditional knockout models can reveal tissue-specific roles, such as in ovarian function.
Point Mutation
Introducing patient-derived missense mutations (e.g., in KARS1) via CRISPR point mutation allows assessment of their impact on tRNA charging, protein stability, and cellular phenotypes, linking genotype to disease.
Knock-in
Knock-in of epitope tags or fluorescent reporters at the endogenous KARS1 locus enables real-time imaging and interactome studies without overexpression artifacts. Knock-in of acetylation or lactylation sites can dissect post-translational regulation.
Overexpression
CRISPR activation (CRISPRa) or cDNA overexpression of KARS1 can model gain-of-function effects, such as enhanced proliferation or drug resistance, and uncover moonlighting functions in cancer.
How EDITGENE Supports lysine-tRNA ligase activity Research
Researchers studying lysine-tRNA ligase activity-related genes often need to determine whether a candidate gene is causally involved in a specific phenotype, such as drug resistance, metabolic reprogramming, or disease development. Precise genetic models are essential to move from correlation to causation.
Contact EDITGENE today to design your custom CRISPR model for lysine-tRNA ligase activity research.
Frequently Asked Questions About lysine-tRNA ligase activity
What is lysine-tRNA ligase activity?
It is the enzymatic activity (GO:0004824) that attaches the amino acid lysine to its corresponding tRNA molecule, a crucial step in protein synthesis.
What genes are involved in lysine-tRNA ligase activity?
The primary gene is KARS1, which encodes lysyl-tRNA synthetase. Other genes like AARS1 can influence related pathways.
What diseases are associated with lysine-tRNA ligase activity?
Mutations in KARS1 are linked to ovarian insufficiency and neurological disorders. The enzyme is also a target for antimalarial drugs.
How is lysine-tRNA ligase activity regulated?
It is regulated by post-translational modifications such as acetylation, alternative splicing, and protein-protein interactions.
What is the reaction catalyzed by lysine-tRNA ligase?
ATP + L-lysine + tRNA(Lys) = AMP + diphosphate + L-lysyl-tRNA(Lys).
Why is lysine-tRNA ligase a drug target?
Because it is essential for protein synthesis in pathogens like Plasmodium, inhibitors can selectively kill parasites.
What are the synonyms for lysine-tRNA ligase activity?
Lysyl-tRNA synthetase activity, lysine translase activity, L-lysine-transfer RNA ligase activity, and others.
How can I study lysine-tRNA ligase activity in the lab?
Common methods include aminoacylation assays, CRISPR knockout, and structural biology.
What is the role of KARS1 in cancer?
KARS1 and related synthetases can promote tumorigenesis through moonlighting functions, such as lactylation of p53 by AARS1.
Can CRISPR be used to model KARS1 mutations?
Yes, CRISPR knockout, point mutation knock-in, and overexpression models are powerful tools to study KARS1 function and disease variants.
Conclusion
Lysine-tRNA ligase activity (GO:0004824) is a cornerstone of protein synthesis with far-reaching implications in human health and disease. Its central role in translation, coupled with emerging moonlighting functions and druggability, makes it a compelling subject for basic and translational research. Advanced CRISPR technologies now enable precise interrogation of KARS1 and related genes, paving the way for novel therapeutic strategies.
References
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- 2. Ju J et al.. 2024. The alanyl-tRNA synthetase AARS1 moonlights as a lactyltransferase to promote YAP signaling in gastric cancer.. J Clin Invest 134(10) PMID: 38512451
- 3. França MM et al.. 2022. Genetics of ovarian insufficiency and defects of folliculogenesis.. Best Pract Res Clin Endocrinol Metab 36(1):101594 PMID: 34794894
- 4. Ye Q et al.. 2017. Acetylation of lysine ϵ-amino groups regulates aminoacyl-tRNA synthetase activity in Escherichia coli.. J Biol Chem 292(25):10709-10722 PMID: 28455447
- 5. Freist W et al.. 1995. Lysyl-tRNA synthetase.. Biol Chem Hoppe Seyler 376(8):451-72 PMID: 7576245
- 6. Forte B et al.. 2026. Structure-Guided Optimization of Novel Inhibitors of Plasmodium Lysyl-tRNA Synthetase with Multistage Activity against Malaria Parasites.. J Med Chem 69(11):13820-13855 PMID: 42227818
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- 8. Shirota FN et al.. 1977. Potential inhibitors of collagen biosynthesis. 5,5-Difluoro-DL-lysine and 5,5-dimethyl-DL-lysine and their activation by lysyl-tRNA ligase.. J Med Chem 20(12):1623-7 PMID: 412965
