GO:0004349 glutamate 5-kinase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004349 (glutamate 5-kinase activity) catalyzes the ATP-dependent phosphorylation of L-glutamate to L-glutamyl 5-phosphate, the first committed step in proline biosynthesis.
• The enzyme belongs to the amino acid kinase family and in bacteria such as Escherichia coli uses a two-domain architecture with a PUA domain that modulates activity.
• Glutamate 5-kinase is feedback-inhibited by proline, which binds at a site overlapping the glutamate substrate site.
• In pathogens like Mycobacterium tuberculosis and Leishmania donovani, glutamate 5-kinase is essential and is being pursued as an antimicrobial drug target.
• Key experimental approaches include X-ray crystallography, site-directed mutagenesis, enzyme kinetics, and CRISPR-based knockout or point-mutation models.
• EDITGENE provides knockout, point-mutation, knock-in, overexpression cell models and CRISPR library screening to study glutamate 5-kinase-related genes.
Description
Glutamate 5-kinase activity (GO:0004349) is a molecular function that catalyzes the reaction L-glutamate + ATP = L-glutamyl 5-phosphate + ADP + H+. This phosphorylation event is the first committed and rate-limiting step in the biosynthesis of proline from glutamate, a pathway conserved from bacteria to plants and protozoa. Because proline is critical for protein synthesis, cellular redox balance, and stress responses, the enzyme that initiates its production is of broad biological and biomedical interest. In bacteria, glutamate 5-kinase is encoded by the proB gene and is feedback-inhibited by the end product proline, ensuring metabolic balance. Structural and biochemical studies have revealed that the enzyme belongs to the amino acid kinase family and possesses a distinctive two-domain architecture, including a PUA domain that influences catalytic efficiency. In protozoan parasites such as Leishmania donovani, a putative glutamate 5-kinase has been characterized, highlighting its potential as a drug target in neglected tropical diseases. In Mycobacterium tuberculosis, allosteric inhibitors of glutamate 5-kinase have been discovered, demonstrating the enzyme's druggability and its essential role in proline auxotrophy. For researchers, GO:0004349 represents a tractable node linking amino acid metabolism, enzyme regulation, and antimicrobial drug discovery.
glutamate 5-kinase activity At A Glance
| GO ID | GO:0004349 |
|---|---|
| GO term | glutamate 5-kinase activity |
| Ontology | molecular_function |
| Synonym | ATP:gamma-L-glutamate phosphotransferase activity; ATP-L-glutamate 5-phosphotransferase activity; ATP:L-glutamate 5-phosphotransferase activity; gamma-glutamate kinase activity; gamma-glutamyl kinase activity; glutamate kinase activity |
| Major function | Catalyzes the ATP-dependent phosphorylation of L-glutamate to L-glutamyl 5-phosphate, the first step in proline biosynthesis |
| Reaction | L-glutamate + ATP = L-glutamyl 5-phosphate + ADP + H+ |
| Enzyme family | Amino acid kinase family (includes PUA domain in some bacterial enzymes) |
| Feedback inhibition | Inhibited by proline, which binds at a site overlapping the glutamate substrate site |
| Pathway | Proline biosynthesis (glutamate to proline) |
What Is GO:0004349?
Glutamate 5-kinase activity (GO:0004349) is defined as the catalysis of the reaction: L-glutamate + ATP = L-glutamyl 5-phosphate + ADP + H+. In other words, it is the enzyme activity that transfers a phosphate group from ATP to the gamma-carboxyl group of L-glutamate, producing L-glutamyl 5-phosphate, ADP, and a proton. This activity is synonymous with ATP:gamma-L-glutamate phosphotransferase, gamma-glutamate kinase, and glutamate kinase.
Why Is glutamate 5-kinase activity Important in Cell Biology?
Glutamate 5-kinase activity is important because it gates the entire proline biosynthetic pathway, controlling the supply of proline for protein synthesis and cellular stress protection. In bacteria, the enzyme is a validated target for antimicrobial development; for example, allosteric inhibitors of Mycobacterium tuberculosis glutamate 5-kinase show activity against the pathogen. In protozoan parasites like Leishmania donovani, the enzyme is essential and represents a potential drug target. Understanding its catalytic mechanism, regulation, and structural features informs drug design and metabolic engineering.
• First committed step in proline biosynthesis from glutamate.
• Feedback-inhibited by proline, a classic example of end-product regulation.
• Essential in Mycobacterium tuberculosis; allosteric inhibitors show anti-tubercular activity.
• Potential drug target in Leishmania donovani and other protozoan parasites.
• Model enzyme for the amino acid kinase family and PUA domain function.
• Relevant to metabolic engineering of proline overproduction in bacteria.
• Links amino acid metabolism to redox balance and stress responses.
• Provides a paradigm for allosteric regulation by a small-molecule metabolite.
Molecular Mechanism of glutamate 5-kinase activity
Substrate binding and catalysis
In simple terms: The enzyme grabs glutamate and ATP, then transfers a phosphate from ATP onto glutamate.
Glutamate 5-kinase binds L-glutamate and ATP in a sequential manner. The gamma-phosphate of ATP is transferred to the gamma-carboxyl group of L-glutamate, forming L-glutamyl 5-phosphate, ADP, and a proton. Active-site residues have been mapped by site-directed mutagenesis, revealing that the substrate glutamate and the feedback inhibitor proline bind at overlapping sites.
Structural architecture and the PUA domain
In simple terms: The enzyme has a two-part structure, and one part (the PUA domain) helps control its activity.
The crystal structure of Escherichia coli glutamate 5-kinase revealed a novel two-domain architecture within the amino acid kinase family. The enzyme contains a PUA domain, and deletion of this domain affects catalytic function, indicating a regulatory or structural role. This architecture is distinct from other amino acid kinases and provides a basis for understanding allosteric regulation.
Feedback inhibition by proline
In simple terms: When proline levels are high, proline binds to the enzyme and stops it from making more proline.
Glutamate 5-kinase is feedback-inhibited by the end product of the pathway, L-proline. The proline binding site overlaps with the glutamate substrate site, so proline acts as a competitive inhibitor. This ensures that proline biosynthesis is shut down when proline is abundant.
Allosteric inhibition and drug targeting
In simple terms: Small molecules can bind to a different site on the enzyme and turn it off, which can kill bacteria.
In Mycobacterium tuberculosis, 3H-pyrrolo[2,3-c]quinolines were discovered as allosteric inhibitors of glutamate 5-kinase, showing activity against the pathogen. This demonstrates that the enzyme is druggable and that allosteric sites can be exploited for antimicrobial development. In Leishmania donovani, a putative glutamate 5-kinase has been characterized, supporting its potential as a target in parasitic diseases.
Key Genes Involved in GO:0004349 glutamate 5-kinase activity
The following genes and proteins are directly implicated in glutamate 5-kinase activity (GO:0004349) and its regulation across species.
| Gene | Major Role | Research Relevance |
|---|---|---|
| proB (E. coli) | Encodes glutamate 5-kinase, first enzyme in proline biosynthesis | Model for enzyme structure, feedback inhibition, and PUA domain function |
| proA (E. coli) | Encodes glutamate-5-semialdehyde dehydrogenase, second step in proline biosynthesis | Pathway context for proB function |
| proC (E. coli) | Encodes pyrroline-5-carboxylate reductase, final step in proline biosynthesis | Pathway context for proB function |
| putA (E. coli) | Bifunctional proline dehydrogenase/Δ1-pyrroline-5-carboxylate dehydrogenase | Links proline catabolism to glutamate 5-kinase regulation |
| Mtb gltB (Rv) | Glutamate 5-kinase in Mycobacterium tuberculosis | Target of allosteric inhibitors with anti-tubercular activity |
| Ld G5K (Leishmania donovani) | Putative glutamate 5-kinase | Potential drug target in leishmaniasis |
| PUA domain (E. coli proB) | Accessory domain in glutamate 5-kinase | Modulates catalytic activity; deletion affects function |
| ATP-binding site residues | Catalytic residues for ATP binding | Mapped by mutagenesis and crystallography |
| Glutamate-binding site residues | Substrate recognition | Overlaps with proline feedback site |
| Proline-binding site residues | Feedback inhibition | Identified by structural and biochemical studies |
| Amino acid kinase family | Enzyme superfamily | Provides evolutionary and structural context |
| Gamma-glutamyl kinase | Synonym for glutamate 5-kinase | Used in older literature |
| Glutamate kinase | Synonym for glutamate 5-kinase | Used in enzyme nomenclature |
| ATP:gamma-L-glutamate phosphotransferase | Systematic name | Enzyme classification |
| L-glutamyl 5-phosphate | Product of the reaction | Intermediate in proline biosynthesis |
| L-glutamate | Substrate | Amino acid precursor |
| L-proline | Feedback inhibitor and end product | Regulates enzyme activity |
How Is glutamate 5-kinase activity Regulated?
Glutamate 5-kinase activity is primarily regulated by feedback inhibition by L-proline, the end product of the pathway. Proline binds to a site that overlaps with the glutamate substrate-binding site, resulting in competitive inhibition. In Escherichia coli, the PUA domain modulates catalytic activity, and its deletion affects enzyme function. In Mycobacterium tuberculosis, allosteric inhibitors bind to a distinct site and inhibit enzyme activity, suggesting additional regulatory pockets. No direct evidence for regulation by mTOR or the integrated stress response is available in the cited literature for this specific enzyme.
glutamate 5-kinase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| Mtb gltB | Tuberculosis | Mycobacterium tuberculosis knockout and inhibitor testing |
| Ld G5K | Leishmaniasis | Leishmania donovani knockout and enzyme assays |
| proB (E. coli) | Proline auxotrophy | E. coli knockout and complementation |
| proB (E. coli) | Feedback regulation | Point mutations in proline-binding site |
| PUA domain | Enzyme activity modulation | Domain deletion mutants |
Tuberculosis
Mycobacterium tuberculosis glutamate 5-kinase is essential for proline biosynthesis and is a validated drug target. Allosteric inhibitors of this enzyme show activity against M. tuberculosis, highlighting its potential for tuberculosis therapy.
Leishmaniasis
Leishmania donovani possesses a putative glutamate 5-kinase that has been biochemically characterized. Because the parasite relies on proline biosynthesis, this enzyme is considered a potential target for anti-leishmanial drugs.
Metabolic disorders and proline metabolism
Disruption of proline biosynthesis, in which glutamate 5-kinase is the first step, can lead to proline auxotrophy and metabolic imbalances. While direct human disease links are not established in the cited literature, the pathway is relevant to hyperprolinemia and related disorders.
From glutamate 5-kinase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is glutamate 5-kinase essential for growth? | CRISPR knockout in bacterial or parasite cells |
| How does proline feedback inhibition work? | Point mutations in the proline-binding site |
| What is the role of the PUA domain? | Domain deletion or knock-in of mutant enzyme |
| Can allosteric inhibitors kill M. tuberculosis? | Overexpression of wild-type and mutant enzyme for inhibitor testing |
| What is the catalytic mechanism? | Tagged knock-in for purification and crystallography |
| How does enzyme level affect proline production? | Overexpression of proB in E. coli |
How to Study the glutamate 5-kinase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzyme-coupled kinetic assay | ADP production or NADH oxidation | Determining Km, Vmax, and inhibitor IC50 |
| X-ray crystallography | Three-dimensional structure | Visualizing active site and allosteric sites |
| Site-directed mutagenesis | Effect of specific residues on activity | Mapping substrate and inhibitor binding sites |
| Isothermal titration calorimetry | Binding affinity of substrates or inhibitors | Characterizing proline binding |
| CRISPR knockout | Gene essentiality | Testing dependence on glutamate 5-kinase |
| Overexpression and purification | Enzyme yield and purity | Structural and biochemical studies |
| Western blot | Protein expression levels | Validating knockout or overexpression |
| Growth assays | Proline auxotrophy | Phenotypic characterization of mutants |
Enzyme kinetics and spectrophotometric assays
Glutamate 5-kinase activity can be measured by coupling the production of ADP to NADH oxidation using pyruvate kinase and lactate dehydrogenase, or by detecting L-glutamyl 5-phosphate. These assays are used to determine kinetic parameters and inhibitor potency.
X-ray crystallography and structural biology
Crystallization of recombinant glutamate 5-kinase, as done for the E. coli enzyme, reveals the two-domain architecture and substrate-binding sites. Co-crystallization with proline or inhibitors identifies allosteric sites.
Site-directed mutagenesis
Mapping active-site residues by alanine scanning and other mutations identifies residues critical for substrate binding and catalysis. This approach has defined the overlapping glutamate and proline sites.
CRISPR-based genetic screens
CRISPR knockout or interference screens can identify genes required for proline biosynthesis and sensitivity to glutamate 5-kinase inhibitors. These screens are applicable in bacterial and parasite models.
How CRISPR Can Be Used to Study GO:0004349 glutamate 5-kinase activity
Knockout
CRISPR knockout of proB or its homologs can create proline auxotrophs, allowing researchers to test whether glutamate 5-kinase is essential under specific conditions. In Mycobacterium tuberculosis, knockout studies support the enzyme's essentiality and validate it as a drug target. In Leishmania donovani, knockout of the putative glutamate 5-kinase can assess its role in parasite survival.
Point Mutation
CRISPR-mediated point mutations can introduce specific amino acid substitutions in the active site or proline-binding site of glutamate 5-kinase. Such mutants help dissect catalytic residues and feedback inhibition, as demonstrated by site-directed mutagenesis studies.
Knock-in
Knock-in of tagged versions of glutamate 5-kinase (e.g., His-tag or GFP) enables purification, localization, and interaction studies. Tagged knock-in models are valuable for structural biology and live-cell imaging.
Overexpression
CRISPR activation or plasmid-based overexpression of proB increases glutamate 5-kinase levels, which can be used to study proline overproduction, feedback resistance, and inhibitor screening. Overexpression in E. coli has been used for enzyme purification and crystallization.
How EDITGENE Supports glutamate 5-kinase activity Research
Researchers studying glutamate 5-kinase activity-related genes often need to determine whether a candidate gene is causally involved in proline biosynthesis, drug resistance, or metabolic regulation. EDITGENE provides a comprehensive suite of CRISPR services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for glutamate 5-kinase activity research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
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| ALDH18A1 Knockout HEK293 Cell Line | EDJ-KQ2614 | Human | 5832 | Details Get a Quote |
| ALDH18A1 Knockout A-549 Cell Line | EDJ-KQ24726 | Human | 5832 | Details Get a Quote |
| ALDH18A1 Knockout HCT 116 Cell Line | EDJ-KQ24728 | Human | 5832 | Details Get a Quote |
| ALDH18A1 Knockout HeLa Cell Line | EDJ-KQ24729 | Human | 5832 | Details Get a Quote |
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Frequently Asked Questions About glutamate 5-kinase activity
What is glutamate 5-kinase activity?
Glutamate 5-kinase activity (GO:0004349) is the enzyme activity that catalyzes the ATP-dependent phosphorylation of L-glutamate to L-glutamyl 5-phosphate, the first step in proline biosynthesis.
What genes are involved in glutamate 5-kinase activity?
The primary gene is proB in Escherichia coli, which encodes glutamate 5-kinase. Homologs exist in Mycobacterium tuberculosis and Leishmania donovani.
What is the reaction catalyzed by glutamate 5-kinase?
The reaction is: L-glutamate + ATP = L-glutamyl 5-phosphate + ADP + H+.
How is glutamate 5-kinase regulated?
It is feedback-inhibited by L-proline, which binds at a site overlapping the glutamate substrate site. In some bacteria, the PUA domain also modulates activity.
Why is glutamate 5-kinase a drug target?
In Mycobacterium tuberculosis, allosteric inhibitors of glutamate 5-kinase show anti-tubercular activity, and in Leishmania donovani the enzyme is essential, making it a potential drug target.
What is the structure of glutamate 5-kinase?
It belongs to the amino acid kinase family and has a two-domain architecture, including a PUA domain in some bacterial enzymes.
What diseases are linked to glutamate 5-kinase?
It is linked to tuberculosis and leishmaniasis as a pathogen drug target, and to proline metabolism disorders in general.
How can I study glutamate 5-kinase activity in the lab?
Common methods include enzyme kinetics, X-ray crystallography, site-directed mutagenesis, and CRISPR knockout or overexpression models.
What are the synonyms for glutamate 5-kinase activity?
Synonyms include ATP:gamma-L-glutamate phosphotransferase activity, gamma-glutamate kinase activity, gamma-glutamyl kinase activity, and glutamate kinase activity.
What is the GO ID for glutamate 5-kinase activity?
The GO ID is GO:0004349, under the molecular_function ontology.
Conclusion
Glutamate 5-kinase activity (GO:0004349) is a fundamental enzymatic function that initiates proline biosynthesis and is tightly regulated by feedback inhibition. Its structural and mechanistic features have been elucidated in model bacteria, and its essentiality in pathogens like Mycobacterium tuberculosis and Leishmania donovani has made it a promising drug target. Continued research using CRISPR-based models and structural biology will further illuminate its role in metabolism and disease.
References
- 1. Sienkiewicz N et al.. 2018. Characterisation of a putative glutamate 5-kinase from Leishmania donovani.. FEBS J 285(14):2662-2678 PMID: 29777624
- 2. Panciera M et al.. 2022. Discovery of 3H-pyrrolo[2,3-c]quinolines with activity against Mycobacterium tuberculosis by allosteric inhibition of the glutamate-5-kinase enzyme.. Eur J Med Chem 232:114206 PMID: 35219949
- 3. Pérez-Arellano I et al.. 2010. Molecular mechanisms modulating glutamate kinase activity. Identification of the proline feedback inhibitor binding site.. J Mol Biol 404(5):890-901 PMID: 20970428
- 4. Marco-Marín C et al.. 2007. A novel two-domain architecture within the amino acid kinase enzyme family revealed by the crystal structure of Escherichia coli glutamate 5-kinase.. J Mol Biol 367(5):1431-46 PMID: 17321544
- 5. Pérez-Arellano I et al.. 2006. Mapping active site residues in glutamate-5-kinase. The substrate glutamate and the feed-back inhibitor proline bind at overlapping sites.. FEBS Lett 580(26):6247-53 PMID: 17069808
- 6. Pérez-Arellano I et al.. 2004. Glutamate-5-kinase from Escherichia coli: gene cloning, overexpression, purification and crystallization of the recombinant enzyme and preliminary X-ray studies.. Acta Crystallogr D Biol Crystallogr 60(Pt 11):2091-4 PMID: 15502337
- 7. Adams E et al.. 1980. Metabolism of proline and the hydroxyprolines.. Annu Rev Biochem 49:1005-61 PMID: 6250440
- 8. Pérez-Arellano I et al.. 2005. Dissection of Escherichia coli glutamate 5-kinase: functional impact of the deletion of the PUA domain.. FEBS Lett 579(30):6903-8 PMID: 16337196
