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Open data
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Basic information
Entry | Database: PDB / ID: 9emb | |||||||||
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Title | Structure of KefC Asp156Asn variant | |||||||||
![]() | Glutathione-regulated potassium-efflux system protein KefC | |||||||||
![]() | TRANSPORT PROTEIN / KefC / Potassium / GSH / Mutant | |||||||||
Function / homology | ![]() glutathione-regulated potassium exporter activity / response to methylglyoxal / potassium:proton antiporter complex / intracellular pH elevation / regulation of pH / antiporter activity / toxic substance binding / proton transmembrane transport / regulation of intracellular pH / potassium ion transport ...glutathione-regulated potassium exporter activity / response to methylglyoxal / potassium:proton antiporter complex / intracellular pH elevation / regulation of pH / antiporter activity / toxic substance binding / proton transmembrane transport / regulation of intracellular pH / potassium ion transport / response to hydrogen peroxide / response to toxic substance / nucleotide binding / enzyme binding / protein homodimerization activity / membrane / plasma membrane Similarity search - Function | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.98 Å | |||||||||
![]() | Gulati, A. / Kokane, S. / Drew, D. | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Structure and mechanism of the K/H exchanger KefC. Authors: Ashutosh Gulati / Surabhi Kokane / Annemarie Perez-Boerema / Claudia Alleva / Pascal F Meier / Rei Matsuoka / David Drew / ![]() Abstract: Intracellular potassium (K) homeostasis is fundamental to cell viability. In addition to channels, K levels are maintained by various ion transporters. One major family is the proton-driven K efflux ...Intracellular potassium (K) homeostasis is fundamental to cell viability. In addition to channels, K levels are maintained by various ion transporters. One major family is the proton-driven K efflux transporters, which in gram-negative bacteria is important for detoxification and in plants is critical for efficient photosynthesis and growth. Despite their importance, the structure and molecular basis for K-selectivity is poorly understood. Here, we report ~3.1 Å resolution cryo-EM structures of the Escherichia coli glutathione (GSH)-gated K efflux transporter KefC in complex with AMP, AMP/GSH and an ion-binding variant. KefC forms a homodimer similar to the inward-facing conformation of Na/H antiporter NapA. By structural assignment of a coordinated K ion, MD simulations, and SSM-based electrophysiology, we demonstrate how ion-binding in KefC is adapted for binding a dehydrated K ion. KefC harbors C-terminal regulator of K conductance (RCK) domains, as present in some bacterial K-ion channels. The domain-swapped helices in the RCK domains bind AMP and GSH and they inhibit transport by directly interacting with the ion-transporter module. Taken together, we propose that KefC is activated by detachment of the RCK domains and that ion selectivity exploits the biophysical properties likewise adapted by K-ion-channels. | |||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 515.5 KB | Display | ![]() |
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PDB format | ![]() | 343 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.5 MB | Display | ![]() |
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Full document | ![]() | 1.5 MB | Display | |
Data in XML | ![]() | 42.4 KB | Display | |
Data in CIF | ![]() | 63.2 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 19816MC ![]() 8bxgC ![]() 8by2C C: citing same article ( M: map data used to model this data |
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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: 61182.238 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() #2: Chemical | #3: 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: Homodimer of KefC Asp156Asn variant / Type: COMPLEX / Entity ID: #1 / Source: RECOMBINANT |
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Source (natural) | Organism: ![]() ![]() |
Source (recombinant) | Organism: ![]() ![]() |
Buffer solution | pH: 7.5 |
Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
Vitrification | Cryogen name: ETHANE |
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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 defocus max: 2000 nm / Nominal defocus min: 600 nm |
Image recording | Electron dose: 54.6 e/Å2 / Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) |
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Processing
CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
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3D reconstruction | Resolution: 2.98 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 327001 / Symmetry type: POINT | ||||||||||||||||||||||||
Refinement | Cross valid method: NONE Stereochemistry target values: GeoStd + Monomer Library + CDL v1.2 | ||||||||||||||||||||||||
Displacement parameters | Biso mean: 115.78 Å2 | ||||||||||||||||||||||||
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