+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-27459 | |||||||||
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Title | MthK-A90L mutant in closed state with 0 Ca2+ | |||||||||
Map data | ||||||||||
Sample |
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Keywords | MTHK / TRANSPORT PROTEIN / ION CHANNEL | |||||||||
Function / homology | Function and homology information monoatomic cation transmembrane transporter activity / potassium ion transport / identical protein binding / metal ion binding / plasma membrane Similarity search - Function | |||||||||
Biological species | Methanothermobacter thermautotrophicus (archaea) | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 3.18 Å | |||||||||
Authors | Agarwal S / Nimigean CM | |||||||||
Funding support | United States, 1 items
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Citation | Journal: Nat Chem Biol / Year: 2024 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 | emd_27459.map.gz | 8.3 MB | EMDB map data format | |
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Header (meta data) | emd-27459-v30.xml emd-27459.xml | 16 KB 16 KB | Display Display | EMDB header |
FSC (resolution estimation) | emd_27459_fsc.xml | 10.7 KB | Display | FSC data file |
Images | emd_27459.png | 45.4 KB | ||
Filedesc metadata | emd-27459.cif.gz | 5.7 KB | ||
Others | emd_27459_half_map_1.map.gz emd_27459_half_map_2.map.gz | 76.2 MB 76.5 MB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-27459 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-27459 | HTTPS FTP |
-Related structure data
Related structure data | 8djbMC 9405C 9406C 9407C 5bkiC 5bkjC 5bkkC 8fz7C M: atomic model generated by this map C: citing same article (ref.) |
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Similar structure data | Similarity search - Function & homologyF&H Search |
-Links
EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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Related items in Molecule of the Month |
-Map
File | Download / File: emd_27459.map.gz / Format: CCP4 / Size: 103 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||
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Voxel size | X=Y=Z: 1.083 Å | ||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Half map: #2
File | emd_27459_half_map_1.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
-Half map: #1
File | emd_27459_half_map_2.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
-Sample components
-Entire : MthK A90L mutant in 0 Ca2+
Entire | Name: MthK A90L mutant in 0 Ca2+ |
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Components |
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-Supramolecule #1: MthK A90L mutant in 0 Ca2+
Supramolecule | Name: MthK A90L mutant in 0 Ca2+ / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1 |
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Source (natural) | Organism: Methanothermobacter thermautotrophicus (archaea) |
Molecular weight | Theoretical: 220 KDa |
-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: Methanothermobacter thermautotrophicus (archaea) |
Molecular weight | Theoretical: 37.398242 KDa |
Recombinant expression | Organism: Escherichia coli (E. coli) |
Sequence | String: MVLVIEIIRK HLPRVLKVPA TRILLLVLAV IIYGTAGFHF IEGESWTVSL YWTFVTIATV GYGDYSPSTP LGMYFTVTLI VLGIGTFAV LVERLLEFLI NREQMKLMGL IDVAKSRHVV ICGWSESTLE CLRELRGSEV FVLAEDENVR KKVLRSGANF V HGDPTRVS ...String: MVLVIEIIRK HLPRVLKVPA TRILLLVLAV IIYGTAGFHF IEGESWTVSL YWTFVTIATV GYGDYSPSTP LGMYFTVTLI VLGIGTFAV LVERLLEFLI 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: POTASSIUM ION
Macromolecule | Name: POTASSIUM ION / type: ligand / ID: 2 / Number of copies: 1 / Formula: K |
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Molecular weight | Theoretical: 39.098 Da |
-Experimental details
-Structure determination
Method | cryo EM |
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Processing | single particle reconstruction |
Aggregation state | particle |
-Sample preparation
Concentration | 7 mg/mL |
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Buffer | pH: 8.5 |
Grid | Model: UltrAuFoil R1.2/1.3 / Material: GOLD / Mesh: 300 / Support film - Material: GOLD / Support film - topology: HOLEY / Pretreatment - Type: GLOW DISCHARGE / Pretreatment - Time: 80 sec. |
Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Instrument: FEI VITROBOT MARK IV / Details: BLOTTING FOR 2 S (BLOT FORCE 1). |
-Electron microscopy
Microscope | FEI TITAN KRIOS |
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Electron beam | Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELDBright-field microscopy / Nominal defocus max: 3.0 µm / Nominal defocus min: 0.5 µm |
Image recording | Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Average electron dose: 65.19 e/Å2 |
Experimental equipment | Model: Titan Krios / Image courtesy: FEI Company |