+Open data
-Basic information
Entry | Database: PDB / ID: 7tj6 | ||||||||||||
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Title | SthK open state, cAMP-bound in the presence of POPA | ||||||||||||
Components | Putative transcriptional regulator, Crp/Fnr family | ||||||||||||
Keywords | TRANSPORT PROTEIN / cyclic nucleotide-gated channel / lipid modulation / pacemaker channel | ||||||||||||
Function / homology | Function and homology information monoatomic ion transmembrane transport / protein-containing complex binding / membrane Similarity search - Function | ||||||||||||
Biological species | Spirochaeta thermophila DSM 6578 (bacteria) | ||||||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.9 Å | ||||||||||||
Authors | Schmidpeter, P.A. / Nimigean, C.M. | ||||||||||||
Funding support | United States, 3items
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Citation | Journal: Nat Struct Mol Biol / Year: 2022 Title: Anionic lipids unlock the gates of select ion channels in the pacemaker family. Authors: Philipp A M Schmidpeter / Di Wu / Jan Rheinberger / Paul M Riegelhaupt / Haiping Tang / Carol V Robinson / Crina M Nimigean / Abstract: Lipids play important roles in regulating membrane protein function, but the molecular mechanisms used are elusive. Here we investigated how anionic lipids modulate SthK, a bacterial pacemaker ...Lipids play important roles in regulating membrane protein function, but the molecular mechanisms used are elusive. Here we investigated how anionic lipids modulate SthK, a bacterial pacemaker channel homolog, and HCN2, whose activity contributes to pacemaking in the heart and brain. Using SthK allowed the reconstitution of purified channels in controlled lipid compositions for functional and structural assays that are not available for the eukaryotic channels. We identified anionic lipids bound tightly to SthK and their exact binding locations and determined that they potentiate channel activity. Cryo-EM structures in the most potentiating lipids revealed an open state and identified a nonannular lipid bound with its headgroup near an intersubunit salt bridge that clamps the intracellular channel gate shut. Breaking this conserved salt bridge abolished lipid modulation in SthK and eukaryotic HCN2 channels, indicating that anionic membrane lipids facilitate channel opening by destabilizing these interactions. Our findings underline the importance of state-dependent protein-lipid interactions. | ||||||||||||
History |
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-Structure visualization
Structure viewer | Molecule: MolmilJmol/JSmol |
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-Downloads & links
-Download
PDBx/mmCIF format | 7tj6.cif.gz | 293.8 KB | Display | PDBx/mmCIF format |
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PDB format | pdb7tj6.ent.gz | 236.6 KB | Display | PDB format |
PDBx/mmJSON format | 7tj6.json.gz | Tree view | PDBx/mmJSON format | |
Others | Other downloads |
-Validation report
Summary document | 7tj6_validation.pdf.gz | 1.9 MB | Display | wwPDB validaton report |
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Full document | 7tj6_full_validation.pdf.gz | 2 MB | Display | |
Data in XML | 7tj6_validation.xml.gz | 64.9 KB | Display | |
Data in CIF | 7tj6_validation.cif.gz | 90.1 KB | Display | |
Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/tj/7tj6 ftp://data.pdbj.org/pub/pdb/validation_reports/tj/7tj6 | HTTPS FTP |
-Related structure data
Related structure data | 25917MC 7tj5C 7tktC M: map data used to model this data C: citing same article (ref.) |
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Similar structure data | Similarity search - Function & homologyF&H Search |
-Links
-Assembly
Deposited unit |
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1 |
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-Components
#1: Protein | Mass: 51118.574 Da / Num. of mol.: 4 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Spirochaeta thermophila DSM 6578 (bacteria) Strain: ATCC 700085 / DSM 6578 / Z-1203 / Gene: Spith_0644 / Production host: Escherichia coli BL21(DE3) (bacteria) / Variant (production host): C41 / References: UniProt: G0GA88 #2: Chemical | ChemComp-CMP / #3: Chemical | ChemComp-D21 / ( Has ligand of interest | Y | |
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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 |
-Sample preparation
Component | Name: open conformation of SthK bound to cAMP / Type: COMPLEX Details: SthK was reconstituted into nanodiscs containing POPA lipids. Entity ID: #1 / Source: RECOMBINANT | |||||||||||||||||||||||||
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Molecular weight | Experimental value: NO | |||||||||||||||||||||||||
Source (natural) | Organism: Spirochaeta thermophila (strain ATCC 700085 / DSM 6578 / Z-1203) (bacteria) | |||||||||||||||||||||||||
Source (recombinant) | Organism: Escherichia coli BL21(DE3) (bacteria) / Strain: C41(DE3) | |||||||||||||||||||||||||
Buffer solution | pH: 7.4 | |||||||||||||||||||||||||
Buffer component |
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Specimen | Conc.: 8 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES Details: WT SthK in MSP1E3 nanodiscs composed of 3:1 DOPC:POPA | |||||||||||||||||||||||||
Specimen support | Grid material: GOLD / Grid type: UltrAuFoil R1.2/1.3 | |||||||||||||||||||||||||
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % / Chamber temperature: 298.15 K |
-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: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
Electron lens | Mode: BRIGHT FIELD / Nominal magnification: 105000 X / Nominal defocus max: 2000 nm / Nominal defocus min: 1000 nm / Cs: 2.7 mm |
Specimen holder | Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
Image recording | Average exposure time: 2.6 sec. / Electron dose: 50.812 e/Å2 / Detector mode: COUNTING / Film or detector model: GATAN K3 (6k x 4k) / Num. of grids imaged: 1 / Num. of real images: 5684 |
EM imaging optics | Energyfilter name: GIF Bioquantum / Energyfilter slit width: 20 eV |
Image scans | Movie frames/image: 50 / Used frames/image: 1-50 |
-Processing
EM software |
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CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||
Particle selection | Num. of particles selected: 1561870 | ||||||||||||||||||||||||||||
Symmetry | Point symmetry: C4 (4 fold cyclic) | ||||||||||||||||||||||||||||
3D reconstruction | Resolution: 2.9 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 202148 / Symmetry type: POINT | ||||||||||||||||||||||||||||
Atomic model building | Protocol: FLEXIBLE FIT / Space: REAL | ||||||||||||||||||||||||||||
Atomic model building | PDB-ID: 6VY0 Accession code: 6VY0 / Source name: PDB / Type: experimental model |