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- PDB-8chb: Inward-facing conformation of the ABC transporter BmrA C436S/A582... -
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Basic information
Entry | Database: PDB / ID: 8chb | ||||||
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Title | Inward-facing conformation of the ABC transporter BmrA C436S/A582C cross-linked mutant | ||||||
![]() | Multidrug resistance ABC transporter ATP-binding/permease protein BmrA | ||||||
![]() | MEMBRANE PROTEIN / ABC transporter / drug efflux pump / homodimer / antibiotic resistance | ||||||
Function / homology | ![]() ATPase-coupled lipid transmembrane transporter activity / Translocases; Catalysing the translocation of other compounds; Linked to the hydrolysis of a nucleoside triphosphate / ABC-type transporter activity / transmembrane transport / response to antibiotic / ATP hydrolysis activity / ATP binding / plasma membrane Similarity search - Function | ||||||
Biological species | ![]() ![]() | ||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.14 Å | ||||||
![]() | Di Cesare, M. / Kaplan, E. / Hanssen, E. / Valimehr, S. / Orelle, C. / Jault, J.M. | ||||||
Funding support | ![]()
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![]() | ![]() Title: The transport activity of the multidrug ABC transporter BmrA does not require a wide separation of the nucleotide-binding domains. Authors: Margot Di Cesare / Elise Kaplan / Julia Rendon / Guillaume Gerbaud / Sepideh Valimehr / Alexia Gobet / Thu-Anh Thi Ngo / Vincent Chaptal / Pierre Falson / Marlène Martinho / Pierre Dorlet / ...Authors: Margot Di Cesare / Elise Kaplan / Julia Rendon / Guillaume Gerbaud / Sepideh Valimehr / Alexia Gobet / Thu-Anh Thi Ngo / Vincent Chaptal / Pierre Falson / Marlène Martinho / Pierre Dorlet / Eric Hanssen / Jean-Michel Jault / Cédric Orelle / ![]() ![]() Abstract: ATP-binding cassette (ABC) transporters are ubiquitous membrane proteins responsible for the translocation of a wide diversity of substrates across biological membranes. Some of them confer multidrug ...ATP-binding cassette (ABC) transporters are ubiquitous membrane proteins responsible for the translocation of a wide diversity of substrates across biological membranes. Some of them confer multidrug or antimicrobial resistance to cancer cells and pathogenic microorganisms, respectively. Despite a wealth of structural data gained in the last two decades, the molecular mechanism of these multidrug efflux pumps remains elusive, including the extent of separation between the two nucleotide-binding domains (NBDs) during the transport cycle. Based on recent outward-facing structures of BmrA, a homodimeric multidrug ABC transporter from Bacillus subtilis, we introduced a cysteine mutation near the C-terminal end of the NBDs to analyze the impact of disulfide-bond formation on BmrA function. Interestingly, the presence of the disulfide bond between the NBDs did not prevent the ATPase, nor did it affect the transport of Hoechst 33342 and doxorubicin. Yet, the 7-amino-actinomycin D was less efficiently transported, suggesting that a further opening of the transporter might improve its ability to translocate this larger compound. We solved by cryo-EM the apo structures of the cross-linked mutant and the WT protein. Both structures are highly similar, showing an intermediate opening between their NBDs while their C-terminal extremities remain in close proximity. Distance measurements obtained by electron paramagnetic resonance spectroscopy support the intermediate opening found in these 3D structures. Overall, our data suggest that the NBDs of BmrA function with a tweezers-like mechanism distinct from the related lipid A exporter MsbA. | ||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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PDBx/mmCIF format | ![]() | 223.3 KB | Display | ![]() |
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PDB format | ![]() | 180.4 KB | Display | ![]() |
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-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 16659MC ![]() 8qoeC 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: 66340.836 Da / Num. of mol.: 2 / Mutation: C436S, A582C Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() References: UniProt: O06967, Translocases; Catalysing the translocation of other compounds; Linked to the hydrolysis of a nucleoside triphosphate |
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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 ATP-binding Cassette Transporter BmrA / Type: COMPLEX / Entity ID: all / Source: RECOMBINANT | |||||||||||||||||||||||||
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Molecular weight | Experimental value: NO | |||||||||||||||||||||||||
Source (natural) | Organism: ![]() ![]() | |||||||||||||||||||||||||
Source (recombinant) | Organism: ![]() ![]() | |||||||||||||||||||||||||
Buffer solution | pH: 8 / Details: pH adjustment with sodium hydroxide | |||||||||||||||||||||||||
Buffer component |
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Specimen | Conc.: 6 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES | |||||||||||||||||||||||||
Specimen support | Grid material: COPPER / Grid mesh size: 300 divisions/in. / Grid type: Quantifoil R1.2/1.3 | |||||||||||||||||||||||||
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 95 % / Chamber temperature: 295.15 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: 81000 X / Nominal defocus max: 2000 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 | Average exposure time: 3.8 sec. / Electron dose: 50 e/Å2 / Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Num. of grids imaged: 1 / Num. of real images: 13937 |
EM imaging optics | Energyfilter name: GIF Bioquantum / Energyfilter slit width: 10 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: 2057656 | ||||||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry: C2 (2 fold cyclic) | ||||||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 3.14 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 343396 / Algorithm: BACK PROJECTION / Num. of class averages: 1 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||
Atomic model building | B value: 90.1 / Protocol: AB INITIO MODEL / Space: REAL | ||||||||||||||||||||||||||||||||||||||||
Refine LS restraints |
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