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Open data
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Basic information
Entry | Database: PDB / ID: 9fxc | |||||||||||||||
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Title | Cryo-EM structure of IrtAB in inward-facing state in nanodisc | |||||||||||||||
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![]() | MEMBRANE PROTEIN / ABC transporter / type IV ABC importer siderophore / mycobactin / heterodimeric ABC transporter | |||||||||||||||
Function / homology | ![]() Translocases; Catalysing the translocation of inorganic cations; Linked to the hydrolysis of a nucleoside triphosphate / ATPase-coupled lipid transmembrane transporter activity / ABC-type transporter activity / oxidoreductase activity / ATP hydrolysis activity / ATP binding / plasma membrane Similarity search - Function | |||||||||||||||
Biological species | ![]() | |||||||||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.6 Å | |||||||||||||||
![]() | Gonda, I. / Seeger, M.A. | |||||||||||||||
Funding support | ![]()
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![]() | ![]() Title: The mycobacterial ABC transporter IrtAB employs a membrane-facing crevice for siderophore-mediated iron uptake. Authors: Imre Gonda / Simona Sorrentino / Laura Galazzo / Nicolas P Lichti / Fabian M Arnold / Ahmad R Mehdipour / Enrica Bordignon / Markus A Seeger / ![]() ![]() Abstract: The mycobacterial ABC transporter IrtAB features an ABC exporter fold, yet it imports iron-charged siderophores called mycobactins. Here, we present extensive cryo-EM analyses and DEER measurements, ...The mycobacterial ABC transporter IrtAB features an ABC exporter fold, yet it imports iron-charged siderophores called mycobactins. Here, we present extensive cryo-EM analyses and DEER measurements, revealing that IrtAB alternates between an inward-facing and an outward-occluded conformation, but does not sample an outward-facing conformation. When IrtAB is locked in its outward-occluded conformation in nanodiscs, mycobactin is bound in the middle of the lipid bilayer at a membrane-facing crevice opening at the heterodimeric interface. Mutations introduced at the crevice abrogate mycobactin import and in corresponding structures, the crevice is collapsed. A conserved triple histidine motif coordinating a zinc ion is present below the mycobactin binding site. Substitution of these histidine residues with alanine results in a decoupled transporter, which hydrolyzes ATP, but lost its capacity to import mycobactins. Our data suggest that IrtAB imports mycobactin via a credit-card mechanism in a transport cycle that is coupled to the presence of zinc. | |||||||||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 446.6 KB | Display | ![]() |
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PDB format | ![]() | 300.3 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.2 MB | Display | ![]() |
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Full document | ![]() | 1.2 MB | Display | |
Data in XML | ![]() | 40.6 KB | Display | |
Data in CIF | ![]() | 63.6 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 50848MC ![]() 9fw3C ![]() 9g2kC ![]() 9g2lC ![]() 9g2mC ![]() 9g2pC ![]() 9g2sC ![]() 9g2tC ![]() 9g2vC ![]() 9g2xC ![]() 9g2yC ![]() 9g2zC ![]() 9g36C ![]() 9g37C ![]() 9gl3C 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: 97496.539 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() Gene: irtA, KEK_01485 / Production host: ![]() ![]() References: UniProt: G7CBF5, Translocases; Catalysing the translocation of inorganic cations; Linked to the hydrolysis of a nucleoside triphosphate | ||||
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#2: Protein | Mass: 61559.539 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Details: contains cleaved, C-terminal 3C enzyme recognition site Source: (gene. exp.) ![]() Gene: irtB, KEK_01490 / Production host: ![]() ![]() References: UniProt: G7CBF6, Translocases; Catalysing the translocation of inorganic cations; Linked to the hydrolysis of a nucleoside triphosphate | ||||
#3: Chemical | Has ligand of interest | Y | Has protein modification | N | |
-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: IrtAB / Type: COMPLEX Details: wild-type IrtAB in nanodisc with ATP-gamma-S substrate in presence of 100uM MBT (unobserved) Entity ID: #1-#2 / Source: RECOMBINANT | |||||||||||||||||||||||||
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Molecular weight | Value: 0.1589 MDa / Experimental value: NO | |||||||||||||||||||||||||
Source (natural) | Organism: ![]() | |||||||||||||||||||||||||
Source (recombinant) | Organism: ![]() ![]() | |||||||||||||||||||||||||
Buffer solution | pH: 7.5 / Details: 20mM Tris-HCl pH 7.5, 150mM NaCl | |||||||||||||||||||||||||
Buffer component |
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Specimen | Conc.: 2 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES Details: Sample was pre-incubated with 5mM ATP-gamma-S, 5mM Mg2+ ions and SybNL5 sybody prior plunge-freezing. | |||||||||||||||||||||||||
Specimen support | Grid material: GOLD / Grid mesh size: 200 divisions/in. / Grid type: Quantifoil R1.2/1.3 | |||||||||||||||||||||||||
Vitrification | Instrument: LEICA EM GP / Cryogen name: ETHANE-PROPANE / Humidity: 90 % / Chamber temperature: 283 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: ![]() |
Electron lens | Mode: BRIGHT FIELD / Nominal magnification: 130000 X / Nominal defocus max: 2200 nm / Nominal defocus min: 800 nm / Calibrated defocus min: 800 nm / Calibrated defocus max: 2200 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: 0.91 sec. / Electron dose: 61 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) / Num. of grids imaged: 1 / Num. of real images: 6702 Details: micrographs were collected in super-resolution mode, 38 frames per movie |
EM imaging optics | Energyfilter name: GIF Bioquantum / Energyfilter slit width: 20 eV |
Image scans | Width: 11520 / Height: 8184 |
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Processing
EM software |
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CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry: C1 (asymmetric) | ||||||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 3.6 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 142659 / Algorithm: BACK PROJECTION / Num. of class averages: 1 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||
Atomic model building | Space: REAL | ||||||||||||||||||||||||||||||||||||||||
Atomic model building | PDB-ID: 6TEJ Accession code: 6TEJ / Source name: PDB / Type: experimental model | ||||||||||||||||||||||||||||||||||||||||
Refinement | Cross valid method: NONE Stereochemistry target values: GeoStd + Monomer Library + CDL v1.2 | ||||||||||||||||||||||||||||||||||||||||
Displacement parameters | Biso mean: 46.01 Å2 | ||||||||||||||||||||||||||||||||||||||||
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