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- PDB-9i0m: Mycobacterium smegmatis inosine monophosphate dehydrogenase (IMPD... -
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Open data
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Basic information
Entry | Database: PDB / ID: 9i0m | ||||||
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Title | Mycobacterium smegmatis inosine monophosphate dehydrogenase (IMPDH) saturating ATP+IMP-bound form, extended | ||||||
![]() | Inosine-5'-monophosphate dehydrogenase | ||||||
![]() | OXIDOREDUCTASE / Octamer / ligand complex / Purine metabolism / IMPDH | ||||||
Function / homology | ![]() IMP dehydrogenase activity / IMP dehydrogenase / GMP biosynthetic process / GTP biosynthetic process / nucleotide binding / metal ion binding Similarity search - Function | ||||||
Biological species | ![]() | ||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.01 Å | ||||||
![]() | Bulvas, O. / Kouba, T. / Pichova, I. | ||||||
Funding support | European Union, 1items
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![]() | ![]() Title: Conformational landscape of the mycobacterial inosine 5'-monophosphate dehydrogenase octamerization interface. Authors: Ondřej Bulvas / Zdeněk Knejzlík / Anatolij Filimoněnko / Tomáš Kouba / Iva Pichová / ![]() Abstract: Inosine 5'-monophosphate dehydrogenase (IMPDH), a key enzyme in bacterial purine metabolism, plays an essential role in the biosynthesis of guanine nucleotides and shows promise as a target for ...Inosine 5'-monophosphate dehydrogenase (IMPDH), a key enzyme in bacterial purine metabolism, plays an essential role in the biosynthesis of guanine nucleotides and shows promise as a target for antimicrobial drug development. Despite its significance, the conformational dynamics and substrate-induced structural changes in bacterial IMPDH remain poorly understood, particularly with respect to its octameric assembly. Using cryo-EM, we present full-length structures of IMPDH from Mycobacterium smegmatis (MsmIMPDH) captured in a reaction intermediate state, revealing conformational changes upon substrate binding. The structures feature resolved flexible loops that coordinate the binding of the substrate, the cofactor, and the K ion. Our structural analysis identifies a novel octamerization interface unique to MsmIMPDH. Additionally, a previously unobserved barrel-like density suggests potential self-interactions within the C-terminal regions, hinting at a regulatory mechanism tied to assembly and function of the enzyme. These data provide insights into substrate-induced conformational dynamics and novel interaction interfaces in MsmIMPDH, potentially informing the development of IMPDH-targeted drugs. | ||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 653.4 KB | Display | ![]() |
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PDB format | ![]() | 430.8 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 52561MC ![]() 9i0kC ![]() 9i0lC C: citing same article ( M: map data used to model this data |
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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: 53388.988 Da / Num. of mol.: 8 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() Strain: MC2 155 / Gene: guaB, MSMEG_1602 / Plasmid: pRSFDuet-1 / Production host: ![]() ![]() #2: Chemical | ChemComp-IMP / #3: Chemical | ChemComp-K / Has ligand of interest | N | Has protein modification | N | |
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-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
Component | Name: Octameric assembly of inosine monophosphate dehydrogenase in complex with ATP+IMP Type: COMPLEX / Entity ID: #1 / Source: RECOMBINANT | |||||||||||||||||||||||||||||||||||
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Molecular weight | Experimental value: NO | |||||||||||||||||||||||||||||||||||
Source (natural) | Organism: ![]() | |||||||||||||||||||||||||||||||||||
Source (recombinant) | Organism: ![]() ![]() | |||||||||||||||||||||||||||||||||||
Buffer solution | pH: 7.5 Details: 50 mM HEPES (pH 7.5), 200 mM KCl, 5 mM DTT, 22 mM MgCl2 Ligand: 10 mM ATP + 10 mM IMP | |||||||||||||||||||||||||||||||||||
Buffer component |
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Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES | |||||||||||||||||||||||||||||||||||
Specimen support | Grid material: GOLD / Grid mesh size: 300 divisions/in. / Grid type: Quantifoil R2/1 | |||||||||||||||||||||||||||||||||||
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: TFS KRIOS |
Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD / Nominal magnification: 165000 X / Nominal defocus max: 3000 nm / Nominal defocus min: 1000 nm / Cs: 2.7 mm / Alignment procedure: ZEMLIN TABLEAU |
Specimen holder | Cryogen: NITROGEN |
Image recording | Average exposure time: 2 sec. / Electron dose: 40 e/Å2 / Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Num. of real images: 1867 |
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Processing
EM software | Name: PHENIX / Version: 1.21rc1_5084 / Category: model refinement | ||||||||||||||||||||||||
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CTF correction | Type: PHASE FLIPPING ONLY | ||||||||||||||||||||||||
Particle selection | Num. of particles selected: 906320 | ||||||||||||||||||||||||
3D reconstruction | Resolution: 3.01 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 105158 / Symmetry type: POINT | ||||||||||||||||||||||||
Atomic model building | B value: 64.57 / Protocol: RIGID BODY FIT / Target criteria: CC coefficient Details: Initial fitting was done in UCSF ChimeraX. Model refinement was done by iterative cycles of manual fitting with Coot and ISOLDE and automated fitting with phenix.real_space_refine. | ||||||||||||||||||||||||
Atomic model building | PDB-ID: 8QQV Accession code: 8QQV / Source name: PDB / Type: experimental model | ||||||||||||||||||||||||
Refinement | Cross valid method: NONE Stereochemistry target values: GeoStd + Monomer Library + CDL v1.2 | ||||||||||||||||||||||||
Displacement parameters | Biso mean: 64.68 Å2 | ||||||||||||||||||||||||
Refine LS restraints |
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