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Open data
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Basic information
Entry | Database: PDB / ID: 8zqd | |||||||||||||||||||||
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Title | Anaerobically isolated active [FeFe]-hydrogenase CbA5H | |||||||||||||||||||||
![]() | [FeFe]-hydrogenase | |||||||||||||||||||||
![]() | OXIDOREDUCTASE / [FeFe]-hydrogenases / homodimer / Zn-binding | |||||||||||||||||||||
Function / homology | ![]() ferredoxin hydrogenase activity / 4 iron, 4 sulfur cluster binding / iron ion binding Similarity search - Function | |||||||||||||||||||||
Biological species | ![]() | |||||||||||||||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.21 Å | |||||||||||||||||||||
![]() | Kawamoto, A. / Kurisu, G. | |||||||||||||||||||||
Funding support | ![]() ![]()
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![]() | ![]() Title: Structural determinants of oxygen resistance and Zn-mediated stability of the [FeFe]-hydrogenase from . Authors: Jifu Duan / Andreas Rutz / Akihiro Kawamoto / Shuvankar Naskar / Kristina Edenharter / Silke Leimkühler / Eckhard Hofmann / Thomas Happe / Genji Kurisu / ![]() ![]() Abstract: [FeFe]-hydrogenases catalyze the reversible two-electron reduction of two protons to molecular hydrogen. Although these enzymes are among the most efficient H-converting biocatalysts in nature, their ...[FeFe]-hydrogenases catalyze the reversible two-electron reduction of two protons to molecular hydrogen. Although these enzymes are among the most efficient H-converting biocatalysts in nature, their catalytic cofactor (termed H-cluster) is irreversibly destroyed upon contact with dioxygen. The [FeFe]-hydrogenase CbA5H from has a unique mechanism to protect the H-cluster from oxygen-induced degradation. The protective strategy of CbA5H was proposed based on a partial protein structure of CbA5H's oxygen-shielded form. Here, we present a cryo-EM structure of 2.2 Å resolution from the entire enzyme in its dimeric and active state and elucidate the structural parameters of the reversible cofactor protection mechanism. We found that both subunits of the homodimeric structure of CbA5H have a Zn-binding four-helix domain, which does not play a role in electron transport as described for other complex protein structures. Biochemical data instead confirm that two [4Fe-4S] clusters are responsible for electron transfer in CbA5H, while the identified zinc atom is critical for oligomerization and protein stability. | |||||||||||||||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 253.5 KB | Display | ![]() |
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PDB format | ![]() | 201.2 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.4 MB | Display | ![]() |
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Full document | ![]() | 1.4 MB | Display | |
Data in XML | ![]() | 48.2 KB | Display | |
Data in CIF | ![]() | 72.6 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 60383MC ![]() 9f46C ![]() 9f47C 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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Assembly
Deposited unit | ![]()
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Components
#1: Protein | Mass: 75001.938 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() #2: Chemical | #3: Chemical | ChemComp-SF4 / #4: Chemical | Has ligand of interest | Y | 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: homodimeric structure of the active [FeFe]-hydrogenase CbA5H 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: 8 / Details: 100 mM Tris-HCl, 2mM NaDT | |||||||||||||||
Buffer component |
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Specimen | 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 R1.2/1.3 | |||||||||||||||
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 50 % / Chamber temperature: 278 K / Details: Vitrification carried out in anaerobic condition |
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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: BRIGHT FIELD / Nominal magnification: 105000 X / Nominal defocus max: 2000 nm / Nominal defocus min: 600 nm / Cs: 0.01 mm / C2 aperture diameter: 50 µm / Alignment procedure: ZEMLIN TABLEAU |
Specimen holder | Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
Image recording | Electron dose: 60 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) / Num. of grids imaged: 1 / Num. of real images: 9994 |
EM imaging optics | Energyfilter name: GIF Bioquantum / Energyfilter slit width: 20 eV Spherical aberration corrector: Microscope was modified with a Cs corrector |
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Processing
EM software |
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CTF correction | Type: PHASE FLIPPING ONLY | ||||||||||||||||||||||||||||||||||||||||||||
Particle selection | Num. of particles selected: 7759751 | ||||||||||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry: C2 (2 fold cyclic) | ||||||||||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 2.21 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 175586 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||||||
Atomic model building | Protocol: FLEXIBLE FIT / Space: REAL | ||||||||||||||||||||||||||||||||||||||||||||
Atomic model building | PDB-ID: 6TTL Accession code: 6TTL / Source name: PDB / Type: experimental model | ||||||||||||||||||||||||||||||||||||||||||||
Refine LS restraints |
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