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| | <SX load='6ebm' size='340' side='right' viewer='molstar' caption='[[6ebm]], [[Resolution|resolution]] 4.00Å' scene=''> | | <SX load='6ebm' size='340' side='right' viewer='molstar' caption='[[6ebm]], [[Resolution|resolution]] 4.00Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[6ebm]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6EBM OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6EBM FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[6ebm]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6EBM OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6EBM FirstGlance]. <br> |
| - | </td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=6ebm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6ebm OCA], [http://pdbe.org/6ebm PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6ebm RCSB], [http://www.ebi.ac.uk/pdbsum/6ebm PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6ebm ProSAT]</span></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 4Å</td></tr> |
| | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=6ebm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6ebm OCA], [https://pdbe.org/6ebm PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6ebm RCSB], [https://www.ebi.ac.uk/pdbsum/6ebm PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6ebm ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/KCNA2_RAT KCNA2_RAT]] Mediates the voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient.<ref>PMID:7544443</ref> | + | [https://www.uniprot.org/uniprot/KCNB2_RAT KCNB2_RAT] Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain and smooth muscle cells (PubMed:1550672). Channels open or close in response to the voltage difference across the membrane, letting potassium ions pass in accordance with their electrochemical gradient. Homotetrameric channels mediate a delayed-rectifier voltage-dependent outward potassium current that display rapid activation and slow inactivation in response to membrane depolarization (PubMed:1550672). Can form functional homotetrameric and heterotetrameric channels that contain variable proportions of KCNB1; channel properties depend on the type of alpha subunits that are part of the channel (PubMed:20202934). Can also form functional heterotetrameric channels with other alpha subunits that are non-conducting when expressed alone, such as KCNS1 and KCNS2, creating a functionally diverse range of channel complexes (PubMed:9305895). In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes, making it difficult to assign currents observed in intact tissues to any particular potassium channel family member. Contributes to the delayed-rectifier voltage-gated potassium current in cortical pyramidal neurons and smooth muscle cells (PubMed:1550672, PubMed:20202934).[UniProtKB:A6H8H5]<ref>PMID:1550672</ref> <ref>PMID:20202934</ref> <ref>PMID:9305895</ref> [https://www.uniprot.org/uniprot/KCNA2_RAT KCNA2_RAT] Mediates the voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient.<ref>PMID:7544443</ref> |
| - | <div style="background-color:#fffaf0;">
| + | |
| - | == Publication Abstract from PubMed ==
| + | |
| - | Voltage-activated potassium (Kv) channels open to conduct K(+) ions in response to membrane depolarization, and subsequently enter non-conducting states through distinct mechanisms of inactivation. X-ray structures of detergent-solubilized Kv channels appear to have captured an open state even though a non-conducting C-type inactivated state would predominate in membranes in the absence of a transmembrane voltage. However, structures for a voltage-activated ion channel in a lipid bilayer environment have not yet been reported. Here we report the structure of the Kv1.2-2.1 paddle chimera channel reconstituted into lipid nanodiscs using single-particle cryo-electron microscopy. At a resolution of ~3 A for the cytosolic domain and ~4 A for the transmembrane domain, the structure determined in nanodiscs is similar to the previously determined X-ray structure. Our findings show that large differences in structure between detergent and lipid bilayer environments are unlikely, and enable us to propose possible structural mechanisms for C-type inactivation.
| + | |
| | | | |
| - | Single-particle cryo-EM structure of a voltage-activated potassium channel in lipid nanodiscs.,Matthies D, Bae C, Toombes GE, Fox T, Bartesaghi A, Subramaniam S, Swartz KJ Elife. 2018 Aug 15;7. pii: 37558. doi: 10.7554/eLife.37558. PMID:30109985<ref>PMID:30109985</ref>
| + | ==See Also== |
| - | | + | *[[Potassium channel 3D structures|Potassium channel 3D structures]] |
| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
| + | |
| - | </div>
| + | |
| - | <div class="pdbe-citations 6ebm" style="background-color:#fffaf0;"></div>
| + | |
| | == References == | | == References == |
| | <references/> | | <references/> |
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| | </SX> | | </SX> |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Bae, C]] | + | [[Category: Rattus norvegicus]] |
| - | [[Category: Bartesaghi, A]] | + | [[Category: Bae C]] |
| - | [[Category: Fox, T]] | + | [[Category: Bartesaghi A]] |
| - | [[Category: Matthies, D]] | + | [[Category: Fox T]] |
| - | [[Category: Subramaniam, S]] | + | [[Category: Matthies D]] |
| - | [[Category: Swartz, K J]] | + | [[Category: Subramaniam S]] |
| - | [[Category: Lipid nanodisc]]
| + | [[Category: Swartz KJ]] |
| - | [[Category: Membrane protein]]
| + | |
| - | [[Category: Potassium channel]]
| + | |
| - | [[Category: Transport protein]]
| + | |
| Structural highlights
Function
KCNB2_RAT Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain and smooth muscle cells (PubMed:1550672). Channels open or close in response to the voltage difference across the membrane, letting potassium ions pass in accordance with their electrochemical gradient. Homotetrameric channels mediate a delayed-rectifier voltage-dependent outward potassium current that display rapid activation and slow inactivation in response to membrane depolarization (PubMed:1550672). Can form functional homotetrameric and heterotetrameric channels that contain variable proportions of KCNB1; channel properties depend on the type of alpha subunits that are part of the channel (PubMed:20202934). Can also form functional heterotetrameric channels with other alpha subunits that are non-conducting when expressed alone, such as KCNS1 and KCNS2, creating a functionally diverse range of channel complexes (PubMed:9305895). In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes, making it difficult to assign currents observed in intact tissues to any particular potassium channel family member. Contributes to the delayed-rectifier voltage-gated potassium current in cortical pyramidal neurons and smooth muscle cells (PubMed:1550672, PubMed:20202934).[UniProtKB:A6H8H5][1] [2] [3] KCNA2_RAT Mediates the voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient.[4]
See Also
References
- ↑ Hwang PM, Glatt CE, Bredt DS, Yellen G, Snyder SH. A novel K+ channel with unique localizations in mammalian brain: molecular cloning and characterization. Neuron. 1992 Mar;8(3):473-81. PMID:1550672 doi:10.1016/0896-6273(92)90275-i
- ↑ Kihira Y, Hermanstyne TO, Misonou H. Formation of heteromeric Kv2 channels in mammalian brain neurons. J Biol Chem. 2010 May 14;285(20):15048-15055. PMID:20202934 doi:10.1074/jbc.M109.074260
- ↑ Salinas M, Duprat F, Heurteaux C, Hugnot JP, Lazdunski M. New modulatory alpha subunits for mammalian Shab K+ channels. J Biol Chem. 1997 Sep 26;272(39):24371-9. PMID:9305895 doi:10.1074/jbc.272.39.24371
- ↑ Lev S, Moreno H, Martinez R, Canoll P, Peles E, Musacchio JM, Plowman GD, Rudy B, Schlessinger J. Protein tyrosine kinase PYK2 involved in Ca(2+)-induced regulation of ion channel and MAP kinase functions. Nature. 1995 Aug 31;376(6543):737-45. PMID:7544443 doi:http://dx.doi.org/10.1038/376737a0
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