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Open data
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Basic information
Entry | ![]() | |||||||||
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Title | bbTBA-bound closed MthK channel in nanodisc | |||||||||
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![]() | ion channel / TRANSPORT PROTEIN | |||||||||
Function / homology | ![]() monoatomic cation transmembrane transporter activity / potassium ion transport / identical protein binding / metal ion binding / plasma membrane Similarity search - Function | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 3.5 Å | |||||||||
![]() | Fan C / Nimigean CM | |||||||||
![]() | ![]() Title: Calcium-gated potassium channel blockade via membrane-facing fenestrations. Authors: Chen Fan / Emelie Flood / Nattakan Sukomon / Shubhangi Agarwal / Toby W Allen / Crina M Nimigean / ![]() ![]() ![]() Abstract: Quaternary ammonium blockers were previously shown to bind in the pore to block both open and closed conformations of large-conductance calcium-activated potassium (BK and MthK) channels. Because ...Quaternary ammonium blockers were previously shown to bind in the pore to block both open and closed conformations of large-conductance calcium-activated potassium (BK and MthK) channels. Because blocker entry was assumed through the intracellular entryway (bundle crossing), closed-pore access suggested that the gate was not at the bundle crossing. Structures of closed MthK, a Methanobacterium thermoautotrophicum homolog of BK channels, revealed a tightly constricted intracellular gate, leading us to investigate the membrane-facing fenestrations as alternative pathways for blocker access directly from the membrane. Atomistic free energy simulations showed that intracellular blockers indeed access the pore through the fenestrations, and a mutant channel with narrower fenestrations displayed no closed-state TPeA block at concentrations that blocked the wild-type channel. Apo BK channels display similar fenestrations, suggesting that blockers may use them as access paths into closed channels. Thus, membrane fenestrations represent a non-canonical pathway for selective targeting of specific channel conformations, opening novel ways to selectively drug BK channels. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 5.1 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 10.1 KB 10.1 KB | Display Display | ![]() |
Images | ![]() | 180.5 KB | ||
Filedesc metadata | ![]() | 5.2 KB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Validation report
Summary document | ![]() | 397.8 KB | Display | ![]() |
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Full document | ![]() | 397.4 KB | Display | |
Data in XML | ![]() | 6.1 KB | Display | |
Data in CIF | ![]() | 6.9 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 5bkkMC ![]() 9405C ![]() 9406C ![]() 5bkiC ![]() 5bkjC ![]() 8djbC ![]() 8fz7C C: citing same article ( M: atomic model generated by this map |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
EMDB pages | ![]() ![]() |
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Related items in Molecule of the Month |
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Map
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Voxel size | X=Y=Z: 1.096 Å | ||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
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Sample components
-Entire : MthK
Entire | Name: MthK |
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Components |
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-Supramolecule #1: MthK
Supramolecule | Name: MthK / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1 |
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Source (natural) | Organism: ![]() ![]() |
-Macromolecule #1: Calcium-gated potassium channel MthK
Macromolecule | Name: Calcium-gated potassium channel MthK / type: protein_or_peptide / ID: 1 / Number of copies: 8 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 37.35616 KDa |
Recombinant expression | Organism: ![]() ![]() |
Sequence | String: MVLVIEIIRK HLPRVLKVPA TRILLLVLAV IIYGTAGFHF IEGESWTVSL YWTFVTIATV GYGDYSPSTP LGMYFTVTLI VLGIGTFAV AVERLLEFLI NREQMKLMGL IDVAKSRHVV ICGWSESTLE CLRELRGSEV FVLAEDENVR KKVLRSGANF V HGDPTRVS ...String: MVLVIEIIRK HLPRVLKVPA TRILLLVLAV IIYGTAGFHF IEGESWTVSL YWTFVTIATV GYGDYSPSTP LGMYFTVTLI VLGIGTFAV AVERLLEFLI NREQMKLMGL IDVAKSRHVV ICGWSESTLE CLRELRGSEV FVLAEDENVR KKVLRSGANF V HGDPTRVS DLEKANVRGA RAVIVDLESD SETIHCILGI RKIDESVRII AEAERYENIE QLRMAGADQV ISPFVISGRL MS RSIDDGY EAMFVQDVLA EESTRRMVEV PIPEGSKLEG VSVLDADIHD VTGVIIIGVG RGDELIIDPP RDYSFRAGDI ILG IGKPEE IERLKNYISA UniProtKB: Calcium-gated potassium channel MthK |
-Macromolecule #2: (1R)-2-{[(S)-{[(2S)-2,3-dihydroxypropyl]oxy}(hydroxy)phosphoryl]o...
Macromolecule | Name: (1R)-2-{[(S)-{[(2S)-2,3-dihydroxypropyl]oxy}(hydroxy)phosphoryl]oxy}-1-[(hexadecanoyloxy)methyl]ethyl (9Z)-octadec-9-enoate type: ligand / ID: 2 / Number of copies: 2 / Formula: PGW |
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Molecular weight | Theoretical: 749.007 Da |
-Macromolecule #3: POTASSIUM ION
Macromolecule | Name: POTASSIUM ION / type: ligand / ID: 3 / Number of copies: 3 / Formula: K |
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Molecular weight | Theoretical: 39.098 Da |
-Macromolecule #4: (~{R})-phenyl-[4-[(tributyl-$l^{4}-azanyl)methyl]phenyl]methanol
Macromolecule | Name: (~{R})-phenyl-[4-[(tributyl-$l^{4}-azanyl)methyl]phenyl]methanol type: ligand / ID: 4 / Number of copies: 1 / Formula: YQ4 |
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Molecular weight | Theoretical: 382.602 Da |
Chemical component information | ![]() ChemComp-YQ4: |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Buffer | pH: 8.5 |
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Vitrification | Cryogen name: ETHANE |
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Electron microscopy
Microscope | FEI TALOS ARCTICA |
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Image recording | Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Average electron dose: 52.52 e/Å2 |
Electron beam | Acceleration voltage: 200 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD |
Experimental equipment | ![]() Model: Talos Arctica / Image courtesy: FEI Company |
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Image processing
Startup model | Type of model: EMDB MAP |
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Final reconstruction | Resolution.type: BY AUTHOR / Resolution: 3.5 Å / Resolution method: FSC 0.143 CUT-OFF / Number images used: 260164 |
Initial angle assignment | Type: ANGULAR RECONSTITUTION |
Final angle assignment | Type: PROJECTION MATCHING |