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Open data
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Basic information
Entry | Database: PDB / ID: 7wiz | ||||||
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Title | Structural basis for ligand binding modes of CTP synthase | ||||||
![]() | CTP synthase | ||||||
![]() | LIGASE / filament / CTPS | ||||||
Function / homology | ![]() Interconversion of nucleotide di- and triphosphates / larval lymph gland hemopoiesis / CTP synthase (glutamine hydrolysing) / CTP synthase activity / cytoophidium / 'de novo' CTP biosynthetic process / pyrimidine nucleobase biosynthetic process / CTP biosynthetic process / glutamine metabolic process / ATP binding ...Interconversion of nucleotide di- and triphosphates / larval lymph gland hemopoiesis / CTP synthase (glutamine hydrolysing) / CTP synthase activity / cytoophidium / 'de novo' CTP biosynthetic process / pyrimidine nucleobase biosynthetic process / CTP biosynthetic process / glutamine metabolic process / ATP binding / identical protein binding / cytosol / cytoplasm Similarity search - Function | ||||||
Biological species | ![]() ![]() | ||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.2 Å | ||||||
![]() | Liu, J.L. / Guo, C.J. | ||||||
Funding support | ![]()
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![]() | ![]() Title: Structural basis for ligand binding modes of CTP synthase. Authors: Xian Zhou / Chen-Jun Guo / Chia-Chun Chang / Jiale Zhong / Huan-Huan Hu / Guang-Ming Lu / Ji-Long Liu / ![]() ![]() Abstract: Cytidine triphosphate synthase (CTPS), which comprises an ammonia ligase domain and a glutamine amidotransferase domain, catalyzes the final step of de novo CTP biosynthesis. The activity of CTPS is ...Cytidine triphosphate synthase (CTPS), which comprises an ammonia ligase domain and a glutamine amidotransferase domain, catalyzes the final step of de novo CTP biosynthesis. The activity of CTPS is regulated by the binding of four nucleotides and glutamine. While glutamine serves as an ammonia donor for the ATP-dependent conversion of UTP to CTP, the fourth nucleotide GTP acts as an allosteric activator. Models have been proposed to explain the mechanisms of action at the active site of the ammonia ligase domain and the conformational changes derived by GTP binding. However, actual GTP/ATP/UTP binding modes and relevant conformational changes have not been revealed fully. Here, we report the discovery of binding modes of four nucleotides and a glutamine analog 6-diazo-5-oxo-L-norleucine in CTPS by cryo-electron microscopy with near-atomic resolution. Interactions between GTP and surrounding residues indicate that GTP acts to coordinate reactions at both domains by directly blocking ammonia leakage and stabilizing the ammonia tunnel. Additionally, we observe the ATP-dependent UTP phosphorylation intermediate and determine interacting residues at the ammonia ligase. A noncanonical CTP binding at the ATP binding site suggests another layer of feedback inhibition. Our findings not only delineate the structure of CTPS in the presence of all substrates but also complete our understanding of the underlying mechanisms of the allosteric regulation and CTP synthesis. | ||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 737.7 KB | Display | ![]() |
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PDB format | ![]() | 612.5 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 32541MC ![]() 7dptC ![]() 7dpwC ![]() 7wj4C M: map data used to model this data C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
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Assembly
Deposited unit | ![]()
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1 |
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Components
#1: Protein | Mass: 62443.656 Da / Num. of mol.: 4 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Production host: ![]() ![]() References: UniProt: Q9VUL1, CTP synthase (glutamine hydrolysing) #2: Chemical | ChemComp-GLN / #3: Chemical | ChemComp-ACP / #4: Chemical | ChemComp-UTP / Has ligand of interest | Y | |
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-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: FILAMENT / 3D reconstruction method: single particle reconstruction |
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Sample preparation
Component | Name: Drosophila substrate-bound CTP synthase / Type: ORGANELLE OR CELLULAR COMPONENT / Entity ID: #1 / Source: RECOMBINANT |
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Source (natural) | Organism: ![]() ![]() |
Source (recombinant) | Organism: ![]() ![]() |
Buffer solution | pH: 7.5 |
Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
Vitrification | Cryogen name: ETHANE |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source: ![]() |
Electron lens | Mode: DARK FIELD / Nominal defocus max: 20000 nm / Nominal defocus min: 5000 nm |
Image recording | Electron dose: 50 e/Å2 / Detector mode: SUPER-RESOLUTION / Film or detector model: GATAN K3 (6k x 4k) |
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Processing
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CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
3D reconstruction | Resolution: 3.2 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 209473 / Symmetry type: POINT | ||||||||||||||||||||||||
Refinement | Cross valid method: NONE Stereochemistry target values: GeoStd + Monomer Library + CDL v1.2 | ||||||||||||||||||||||||
Displacement parameters | Biso mean: 49.49 Å2 | ||||||||||||||||||||||||
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