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Open data
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Basic information
| Entry | Database: PDB / ID: 9ryq | ||||||||||||||||||||||||||||||
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| Title | Aquifex aeolicus lumazine synthase R29A mutant 11-pentamer cage | ||||||||||||||||||||||||||||||
Components | 6,7-dimethyl-8-ribityllumazine synthase | ||||||||||||||||||||||||||||||
Keywords | BIOSYNTHETIC PROTEIN / protein cage / protein engineering / self-assembly / geometry / pentamer / encapsulation | ||||||||||||||||||||||||||||||
| Function / homology | Function and homology information6,7-dimethyl-8-ribityllumazine synthase / 6,7-dimethyl-8-ribityllumazine synthase activity / riboflavin synthase complex / riboflavin biosynthetic process / cytoplasm / cytosol Similarity search - Function | ||||||||||||||||||||||||||||||
| Biological species | ![]() Aquifex aeolicus VF5 (bacteria) | ||||||||||||||||||||||||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.08 Å | ||||||||||||||||||||||||||||||
Authors | Koziej, L. / Azuma, Y. | ||||||||||||||||||||||||||||||
| Funding support | Poland, European Union, 4items
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Citation | Journal: Nat Commun / Year: 2026Title: A molecular basis for stoichiometric enzyme encapsulation in the vitamin B2 biosynthesis compartment. Authors: Lukasz Koziej / Jedrzej Pankowski / Monika Stefanska / Daniel Jankowski / Agnieszka Gawin / V Vishal Malolan / Juha T Huiskonen / Takahiro Kosugi / Yusuke Azuma / ![]() Abstract: Encapsulating metabolic enzymes within protein cages enhances catalytic efficiency through substrate channeling. The vitamin B2 biosynthesis system, in which a dodecahedral lumazine synthase (LS) ...Encapsulating metabolic enzymes within protein cages enhances catalytic efficiency through substrate channeling. The vitamin B2 biosynthesis system, in which a dodecahedral lumazine synthase (LS) cage encapsulates a homotrimeric riboflavin synthase (RS), exemplifies this strategy, yet the molecular basis for this stoichiometric enzyme encapsulation has remained elusive. Here, cryogenic electron microscopy structures reveal a hierarchical assembly mechanism that ensures the defined host-guest ratio. RS C-terminal cage-localization signal peptides anchor at LS pentamer-pentamer interfaces early during assembly, stabilizing open intermediates that, together with delayed later-stage cage closure, extend the loading window until guest incorporation is complete. RS spatial occupancy avoids overloading, while a molecular lock upon final closure prevents disassembly. The elucidated anchoring mechanism enabled structure-based phylogenetic analysis across diverse organisms, suggesting multiple independent evolutionary origins of this modular encapsulation strategy. This naturally occurring architecture provides design principles for engineering synthetic catalytic compartments with programmable stoichiometric control. | ||||||||||||||||||||||||||||||
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Structure visualization
| Structure viewer | Molecule: Molmil Jmol/JSmol |
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Downloads & links
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Download
| PDBx/mmCIF format | 9ryq.cif.gz | 1.5 MB | Display | PDBx/mmCIF format |
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| PDB format | pdb9ryq.ent.gz | Display | PDB format | |
| PDBx/mmJSON format | 9ryq.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/ry/9ryq ftp://data.pdbj.org/pub/pdb/validation_reports/ry/9ryq | HTTPS FTP |
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-Related structure data
| Related structure data | ![]() 54389MC ![]() 9ryiC ![]() 9ryjC ![]() 9rykC ![]() 9rymC ![]() 9rynC ![]() 9ryoC ![]() 9rypC ![]() 9ryuC ![]() 9ryvC ![]() 9rywC ![]() 9ryxC M: map data used to model this data C: citing same article ( |
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| Similar structure data | Similarity search - Function & homology F&H Search |
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Links
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Assembly
| Deposited unit | ![]()
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Components
| #1: Protein | Mass: 18040.594 Da / Num. of mol.: 55 Source method: isolated from a genetically manipulated source Details: AaLS R29A mutant / Source: (gene. exp.) ![]() Aquifex aeolicus VF5 (bacteria) / Gene: ribH, aq_132 / Production host: ![]() References: UniProt: O66529, 6,7-dimethyl-8-ribityllumazine synthase 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: Aquifex aeolicus lumazine synthase R29A mutant 11-pentamer cage Type: COMPLEX / Entity ID: all / Source: RECOMBINANT | ||||||||||||||||||||
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| Molecular weight | Value: 1 MDa / Experimental value: YES | ||||||||||||||||||||
| Source (natural) | Organism: ![]() Aquifex aeolicus VF5 (bacteria) | ||||||||||||||||||||
| Source (recombinant) | Organism: ![]() | ||||||||||||||||||||
| Buffer solution | pH: 8 | ||||||||||||||||||||
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| Specimen | Conc.: 1 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES | ||||||||||||||||||||
| Specimen support | Grid material: COPPER / Grid mesh size: 200 divisions/in. / Grid type: Quantifoil R2/1 | ||||||||||||||||||||
| Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % / Chamber temperature: 277 K |
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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: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 2100 nm / Nominal defocus min: 600 nm / Cs: 2.7 mm / C2 aperture diameter: 50 µm / Alignment procedure: COMA FREE |
| Specimen holder | Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
| Image recording | Electron dose: 40 e/Å2 / Film or detector model: GATAN K3 BIOCONTINUUM (6k x 4k) / Num. of grids imaged: 1 / Num. of real images: 5306 |
| EM imaging optics | Energyfilter name: GIF Bioquantum / Energyfilter slit width: 20 eV |
| Image scans | Width: 5760 / Height: 4092 |
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Processing
| EM software |
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| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||||||||||||||||||
| Particle selection | Num. of particles selected: 1760989 / Details: 3D template picking | ||||||||||||||||||||||||||||||||||||||||||||
| Symmetry | Point symmetry: C5 (5 fold cyclic) | ||||||||||||||||||||||||||||||||||||||||||||
| 3D reconstruction | Resolution: 2.08 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 32433 / Algorithm: FOURIER SPACE / Num. of class averages: 1 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||||||
| Atomic model building | Protocol: RIGID BODY FIT / Space: REAL Details: Initial fitting was done using ChimeraX. Flexible fitting was done using Isolde. | ||||||||||||||||||||||||||||||||||||||||||||
| Atomic model building | PDB-ID: 1HQK Accession code: 1HQK / Details: lumazine synthase / Source name: PDB / Type: experimental model |
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About Yorodumi





Aquifex aeolicus VF5 (bacteria)
Poland, European Union, 4items
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PDBj

FIELD EMISSION GUN
