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- PDB-7pcf: Human methemoglobin bound to Staphylococcus aureus hemophore IsdB -
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Open data
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Basic information
Entry | Database: PDB / ID: 7pcf | ||||||
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Title | Human methemoglobin bound to Staphylococcus aureus hemophore IsdB | ||||||
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![]() | METAL TRANSPORT / Iron acquisition / Hemophore / Hemoglobin / NEAT domain | ||||||
Function / homology | ![]() heme transmembrane transporter activity / nitric oxide transport / hemoglobin alpha binding / cellular oxidant detoxification / hemoglobin binding / renal absorption / haptoglobin-hemoglobin complex / organic acid binding / hemoglobin complex / oxygen transport ...heme transmembrane transporter activity / nitric oxide transport / hemoglobin alpha binding / cellular oxidant detoxification / hemoglobin binding / renal absorption / haptoglobin-hemoglobin complex / organic acid binding / hemoglobin complex / oxygen transport / Scavenging of heme from plasma / endocytic vesicle lumen / blood vessel diameter maintenance / hydrogen peroxide catabolic process / oxygen carrier activity / carbon dioxide transport / Heme signaling / Erythrocytes take up oxygen and release carbon dioxide / Erythrocytes take up carbon dioxide and release oxygen / Late endosomal microautophagy / Cytoprotection by HMOX1 / response to hydrogen peroxide / oxygen binding / regulation of blood pressure / platelet aggregation / Chaperone Mediated Autophagy / positive regulation of nitric oxide biosynthetic process / tertiary granule lumen / Factors involved in megakaryocyte development and platelet production / blood microparticle / ficolin-1-rich granule lumen / iron ion binding / heme binding / Neutrophil degranulation / extracellular space / extracellular exosome / extracellular region / membrane / metal ion binding / cytosol Similarity search - Function | ||||||
Biological species | ![]() ![]() | ||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 5.82 Å | ||||||
![]() | De Bei, O. / Gianquinto, E. / Chirgadze, D.Y. / Hardwick, S.W. / Spyrakis, F. / Luisi, B.F. / Campanini, B. | ||||||
Funding support | ![]()
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![]() | ![]() Title: Cryo-EM structures of staphylococcal IsdB bound to human hemoglobin reveal the process of heme extraction. Authors: Omar De Bei / Marialaura Marchetti / Luca Ronda / Eleonora Gianquinto / Loretta Lazzarato / Dimitri Y Chirgadze / Steven W Hardwick / Lee R Cooper / Francesca Spyrakis / Ben F Luisi / ...Authors: Omar De Bei / Marialaura Marchetti / Luca Ronda / Eleonora Gianquinto / Loretta Lazzarato / Dimitri Y Chirgadze / Steven W Hardwick / Lee R Cooper / Francesca Spyrakis / Ben F Luisi / Barbara Campanini / Stefano Bettati / ![]() ![]() Abstract: Iron surface determinant B (IsdB) is a hemoglobin (Hb) receptor essential for hemic iron acquisition by Staphylococcus aureus. Heme transfer to IsdB is possible from oxidized Hb (metHb), but ...Iron surface determinant B (IsdB) is a hemoglobin (Hb) receptor essential for hemic iron acquisition by Staphylococcus aureus. Heme transfer to IsdB is possible from oxidized Hb (metHb), but inefficient from Hb either bound to oxygen (oxyHb) or bound to carbon monoxide (HbCO), and encompasses a sequence of structural events that are currently poorly understood. By single-particle cryo-electron microscopy, we determined the structure of two IsdB:Hb complexes, representing key species along the heme extraction pathway. The IsdB:HbCO structure, at 2.9-Å resolution, provides a snapshot of the preextraction complex. In this early stage of IsdB:Hb interaction, the hemophore binds to the β-subunits of the Hb tetramer, exploiting a folding-upon-binding mechanism that is likely triggered by a cis/trans isomerization of Pro173. Binding of IsdB to α-subunits occurs upon dissociation of the Hb tetramer into α/β dimers. The structure of the IsdB:metHb complex reveals the final step of the extraction process, where heme transfer to IsdB is completed. The stability of the complex, both before and after heme transfer from Hb to IsdB, is influenced by isomerization of Pro173. These results greatly enhance current understanding of structural and dynamic aspects of the heme extraction mechanism by IsdB and provide insight into the interactions that stabilize the complex before the heme transfer event. This information will support future efforts to identify inhibitors of heme acquisition by S. aureus by interfering with IsdB:Hb complex formation. | ||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 151.5 KB | Display | ![]() |
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PDB format | ![]() | 99.8 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.3 MB | Display | ![]() |
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Full document | ![]() | 1.3 MB | Display | |
Data in XML | ![]() | 34.6 KB | Display | |
Data in CIF | ![]() | 55.7 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 13319MC ![]() 7pchC ![]() 7pcqC 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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Components
#1: Protein | Mass: 15150.353 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() |
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#2: Protein | Mass: 15890.198 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() |
#3: Protein | Mass: 43393.129 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() Gene: isdB, frpB, sasJ, sirH, MW1011 / Plasmid: pASK-IBA3plus / Production host: ![]() ![]() |
#4: Chemical | |
Has ligand of interest | Y |
-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
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Molecular weight | Value: 0.119 MDa / Experimental value: NO | ||||||||||||||||||||||||
Source (natural) |
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Source (recombinant) | Organism: ![]() ![]() | ||||||||||||||||||||||||
Buffer solution | pH: 7.2 Details: CHAPSO was added immediately before plunge freezing to overcome preferred orientation of the particles in the vitreous ice. | ||||||||||||||||||||||||
Buffer component |
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Specimen | Conc.: 2 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES | ||||||||||||||||||||||||
Specimen support | Details: The grid was discharged on both sides. / Grid material: GOLD / Grid mesh size: 300 divisions/in. / Grid type: UltrAuFoil R1.2/1.3 | ||||||||||||||||||||||||
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 99 % / Chamber temperature: 277.15 K |
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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: 130000 X / Nominal defocus max: 3100 nm / Nominal defocus min: 1000 nm / Cs: 2.7 mm / C2 aperture diameter: 50 µm |
Specimen holder | Cryogen: NITROGEN |
Image recording | Electron dose: 39.59 e/Å2 / Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Num. of grids imaged: 1 / Num. of real images: 3051 |
EM imaging optics | Energyfilter slit width: 20 eV |
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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: 521822 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry: C1 (asymmetric) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 5.82 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 103653 / Num. of class averages: 1 / Symmetry type: POINT | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Atomic model building | Protocol: RIGID BODY FIT / Space: REAL | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Atomic model building |
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