A0AAJ2QKR5 · A0AAJ2QKR5_9ACTN
- ProteinCTP synthase
- GenepyrG
- StatusUniProtKB unreviewed (TrEMBL)
- Organism
- Amino acids549 (go to sequence)
- Protein existenceInferred from homology
- Annotation score3/5
Function
function
Catalyzes the ATP-dependent amination of UTP to CTP with either L-glutamine or ammonia as the source of nitrogen. Regulates intracellular CTP levels through interactions with the four ribonucleotide triphosphates.
Miscellaneous
CTPSs have evolved a hybrid strategy for distinguishing between UTP and CTP. The overlapping regions of the product feedback inhibitory and substrate sites recognize a common feature in both compounds, the triphosphate moiety. To differentiate isosteric substrate and product pyrimidine rings, an additional pocket far from the expected kinase/ligase catalytic site, specifically recognizes the cytosine and ribose portions of the product inhibitor.
Catalytic activity
- ATP + H2O + L-glutamine + UTP = ADP + CTP + 2 H+ + L-glutamate + phosphate
- ATP + NH4+ + UTP = ADP + CTP + 2 H+ + phosphate
- H2O + L-glutamine = L-glutamate + NH4+
Activity regulation
Allosterically activated by GTP, when glutamine is the substrate; GTP has no effect on the reaction when ammonia is the substrate. The allosteric effector GTP functions by stabilizing the protein conformation that binds the tetrahedral intermediate(s) formed during glutamine hydrolysis. Inhibited by the product CTP, via allosteric rather than competitive inhibition.
Pathway
Pyrimidine metabolism; CTP biosynthesis via de novo pathway; CTP from UDP: step 2/2.
Features
Showing features for binding site, active site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 19 | CTP (UniProtKB | ChEBI); allosteric inhibitor | ||||
Sequence: S | ||||||
Binding site | 19 | UTP (UniProtKB | ChEBI) | ||||
Sequence: S | ||||||
Binding site | 20-25 | ATP (UniProtKB | ChEBI) | ||||
Sequence: SLGKGL | ||||||
Binding site | 77 | ATP (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 77 | Mg2+ (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 146 | Mg2+ (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Binding site | 153-155 | CTP (UniProtKB | ChEBI); allosteric inhibitor | ||||
Sequence: DIE | ||||||
Binding site | 193-198 | CTP (UniProtKB | ChEBI); allosteric inhibitor | ||||
Sequence: KTKPTQ | ||||||
Binding site | 193-198 | UTP (UniProtKB | ChEBI) | ||||
Sequence: KTKPTQ | ||||||
Binding site | 229 | CTP (UniProtKB | ChEBI); allosteric inhibitor | ||||
Sequence: K | ||||||
Binding site | 229 | UTP (UniProtKB | ChEBI) | ||||
Sequence: K | ||||||
Binding site | 247 | ATP (UniProtKB | ChEBI) | ||||
Sequence: A | ||||||
Binding site | 360 | L-glutamine (UniProtKB | ChEBI) | ||||
Sequence: G | ||||||
Active site | 387 | Nucleophile | ||||
Sequence: C | ||||||
Active site | 387 | Nucleophile; for glutamine hydrolysis | ||||
Sequence: C | ||||||
Binding site | 388-391 | L-glutamine (UniProtKB | ChEBI) | ||||
Sequence: LGLQ | ||||||
Binding site | 411 | L-glutamine (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Binding site | 473 | L-glutamine (UniProtKB | ChEBI) | ||||
Sequence: R | ||||||
Active site | 521 | |||||
Sequence: H | ||||||
Active site | 523 | |||||
Sequence: E |
GO annotations
Aspect | Term | |
---|---|---|
Molecular Function | ligase activity |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameCTP synthase
- EC number
- Alternative names
Gene names
Organism names
- Organism
- Strain
- Taxonomic lineageBacteria > Actinomycetota > Actinomycetes > Kitasatosporales > Streptomycetaceae > Streptomyces
Accessions
- Primary accessionA0AAJ2QKR5
Proteomes
Interaction
Subunit
Homotetramer.
Structure
Family & Domains
Features
Showing features for region, domain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Region | 1-272 | Amidoligase domain | ||||
Sequence: MPPKSSTTKHIFVTGGVASSLGKGLTASSLGMLLKARGLRVVMQKLDPYLNVDPGTMNPFQHGEVFVTNDGAETDLDIGHYERFLDRDLDGSANVTTGQVYSTVIAKERRGEYLGDTVQVIPHITNEIKHRIRRMATDEVDVVITEVGGTVGDIESLPFLETVRQVRHEVGRDNVFVVHISLLPYIGPSGELKTKPTQHSVAALRNIGIQPDAIVLRCDREVPTAIKRKISLMCDVDEAAVVACPDARSIYDIPKVIHTEGLDAYVVRRMDL | ||||||
Domain | 9-272 | CTP synthase N-terminal | ||||
Sequence: KHIFVTGGVASSLGKGLTASSLGMLLKARGLRVVMQKLDPYLNVDPGTMNPFQHGEVFVTNDGAETDLDIGHYERFLDRDLDGSANVTTGQVYSTVIAKERRGEYLGDTVQVIPHITNEIKHRIRRMATDEVDVVITEVGGTVGDIESLPFLETVRQVRHEVGRDNVFVVHISLLPYIGPSGELKTKPTQHSVAALRNIGIQPDAIVLRCDREVPTAIKRKISLMCDVDEAAVVACPDARSIYDIPKVIHTEGLDAYVVRRMDL | ||||||
Domain | 307-540 | Glutamine amidotransferase | ||||
Sequence: LPDAYLSVTEALRAGGFANKARVKIKWVTSDDCKTPAGARAQLGDVDAICIPGGFGERGVTGKVGAIQYARENGIPLLGLCLGLQCIVVEAARNLAGVADANSTEFDPATAHPVVSTMAEQLDIVAGEGDMGGTMRLGMYPAKLAEGSIVREVYDGKEYVEERHRHRYEVNNAYRAELEKKAGIVFSGTSPDGKLVEYVEYPRDVHPYLVATQAHPELRSRPTRPHPLFAGLVK |
Sequence similarities
Belongs to the CTP synthase family.
Keywords
- Domain
Family and domain databases
Sequence
- Sequence statusComplete
- Length549
- Mass (Da)60,103
- Last updated2024-07-24 v1
- Checksum43419C4AEF67B146