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Voltage-gated potassium channel

August 26, 2023

Voltage-gated potassium channels (VGKCs) are transmembrane channels specific for potassium and sensitive to voltage changes in the cell's membrane potential. During action potentials, they play a crucial role in returning the depolarized cell to a resting state.

Eukaryotic potassium channel
Potassium channel, structure in a membrane-like environment. Calculated hydrocarbon boundaries of the lipid bilayer are indicated by red and blue dots.
Identifiers
SymbolIon_trans
PfamPF00520
InterProIPR005821
SCOP21bl8 / SCOPe / SUPFAM
TCDB1.A.1
OPM superfamily8
OPM protein2a79
Membranome217
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
Ion channel (bacterial)
Potassium channel KcsA. Calculated hydrocarbon boundaries of the lipid bilayer are indicated by red and blue dots.
Identifiers
SymbolIon_trans_2
PfamPF07885
InterProIPR013099
SCOP21bl8 / SCOPe / SUPFAM
OPM protein1r3j
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
Slow voltage-gated potassium channel (Potassium channel, voltage-dependent, beta subunit, KCNE)
Identifiers
SymbolISK_Channel
PfamPF02060
InterProIPR000369
TCDB8.A.10
Membranome218
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
KCNQ voltage-gated potassium channel
Identifiers
SymbolKCNQ_channel
PfamPF03520
InterProIPR013821
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
Kv2 voltage-gated K+ channel
Identifiers
SymbolKv2channel
PfamPF03521
InterProIPR003973
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary

Classification Edit

Alpha subunits Edit

Alpha subunits form the actual conductance pore. Based on sequence homology of the hydrophobic transmembrane cores, the alpha subunits of voltage-gated potassium channels are grouped into 12 classes. These are labeled Kvα1-12.[1] The following is a list of the 40 known human voltage-gated potassium channel alpha subunits grouped first according to function and then subgrouped according to the Kv sequence homology classification scheme:

Delayed rectifier Edit

slowly inactivating or non-inactivating

A-type potassium channel Edit

rapidly inactivating

  • Kvα1.x - Shaker-related: Kv1.4 (KCNA4)
  • Kvα4.x - Shal-related: Kv4.1 (KCND1), Kv4.2 (KCND2), Kv4.3 (KCND3)

Outward-rectifying Edit

Inwardly-rectifying Edit

Passes current more easily in the inward direction (into the cell, from outside).

Slowly activating Edit

Modifier/silencer Edit

Unable to form functional channels as homotetramers but instead heterotetramerize with Kvα2 family members to form conductive channels.

Beta subunits Edit

Beta subunits are auxiliary proteins that associate with alpha subunits, sometimes in a α4β4 stoichiometry.[2] These subunits do not conduct current on their own but rather modulate the activity of Kv channels.[3]

Proteins minK and MiRP1 are putative hERG beta subunits.[6]

Animal research Edit

The voltage-gated K+ channels that provide the outward currents of action potentials have similarities to bacterial K+ channels.

These channels have been studied by X-ray diffraction, allowing determination of structural features at atomic resolution.

The function of these channels is explored by electrophysiological studies.

Genetic approaches include screening for behavioral changes in animals with mutations in K+ channel genes. Such genetic methods allowed the genetic identification of the "Shaker" K+ channel gene in Drosophila before ion channel gene sequences were well known.

Study of the altered properties of voltage-gated K+ channel proteins produced by mutated genes has helped reveal the functional roles of K+ channel protein domains and even individual amino acids within their structures.

Structure Edit

Typically, vertebrate voltage-gated K+ channels are tetramers of four identical subunits arranged as a ring, each contributing to the wall of the trans-membrane K+ pore. Each subunit is composed of six membrane spanning hydrophobic α-helical sequences, as well as a voltage sensor in S4. The intracellular side of the membrane contains both amino and carboxy termini.[7] The high resolution crystallographic structure of the rat Kvα1.2/β2 channel has recently been solved (Protein Databank Accession Number 2A79​),[8] and then refined in a lipid membrane-like environment (PDB: 2r9r​).

Selectivity Edit

Main article: Potassium channel § Selectivity filter

Voltage-gated K+ channels are selective for K+ over other cations such as Na+. There is a selectivity filter at the narrowest part of the transmembrane pore.

Channel mutation studies have revealed the parts of the subunits that are essential for ion selectivity. They include the amino acid sequence (Thr-Val-Gly-Tyr-Gly) or (Thr-Val-Gly-Phe-Gly) typical to the selectivity filter of voltage-gated K+ channels. As K+ passes through the pore, interactions between potassium ions and water molecules are prevented and the K+ interacts with specific atomic components of the Thr-Val-Gly-[YF]-Gly sequences from the four channel subunits [1].

It may seem counterintuitive that a channel should allow potassium ions but not the smaller sodium ions through. However in an aqueous environment, potassium and sodium cations are solvated by water molecules. When moving through the selectivity filter of the potassium channel, the water-K+ interactions are replaced by interactions between K+ and carbonyl groups of the channel protein. The diameter of the selectivity filter is ideal for the potassium cation, but too big for the smaller sodium cation. Hence the potassium cations are well "solvated" by the protein carbonyl groups, but these same carbonyl groups are too far apart to adequately solvate the sodium cation. Hence, the passage of potassium cations through this selectivity filter is strongly favored over sodium cations.

Open and closed conformations Edit

The structure of the mammalian voltage-gated K+ channel has been used to explain its ability to respond to the voltage across the membrane. Upon opening of the channel, conformational changes in the voltage-sensor domains (VSD) result in the transfer of 12-13 elementary charges across the membrane electric field. This charge transfer is measured as a transient capacitive current that precedes opening of the channel. Several charged residues of the VSD, in particular four arginine residues located regularly at every third position on the S4 segment, are known to move across the transmembrane field and contribute to the gating charge. The position of these arginines, known as gating arginines, are highly conserved in all voltage-gated potassium, sodium, or calcium channels. However, the extent of their movement and their displacement across the transmembrane potential has been subject to extensive debate.[9] Specific domains of the channel subunits have been identified that are responsible for voltage-sensing and converting between the open and closed conformations of the channel. There are at least two closed conformations. In the first, the channel can open if the membrane potential becomes more positive. This type of gating is mediated by a voltage-sensing domain that consists of the S4 alpha helix that contains 6–7 positive charges. Changes in membrane potential cause this alpha helix to move in the lipid bilayer. This movement in turn results in a conformational change in the adjacent S5–S6 helices that form the channel pore and cause this pore to open or close. In the second, "N-type" inactivation, voltage-gated K+ channels inactivate after opening, entering a distinctive, closed conformation. In this inactivated conformation, the channel cannot open, even if the transmembrane voltage is favorable. The amino terminal domain of the K+ channel or an auxiliary protein can mediate "N-type" inactivation. The mechanism of this type of inactivation has been described as a "ball and chain" model, where the N-terminus of the protein forms a ball that is tethered to the rest of the protein through a loop (the chain).[10] The tethered ball blocks the inner porehole, preventing ion movement through the channel.[11][12]

Pharmacology Edit

For blockers and activators of voltage gated potassium channels see: potassium channel blocker and potassium channel opener.

See also Edit

References Edit

  1. ^ Gutman GA, Chandy KG, Grissmer S, Lazdunski M, McKinnon D, Pardo LA, Robertson GA, Rudy B, Sanguinetti MC, Stühmer W, Wang X (December 2005). "International Union of Pharmacology. LIII. Nomenclature and molecular relationships of voltage-gated potassium channels". Pharmacological Reviews. 57 (4): 473–508. doi:10.1124/pr.57.4.10. PMID 16382104. S2CID 219195192.
  2. ^ Pongs O, Leicher T, Berger M, Roeper J, Bähring R, Wray D, Giese KP, Silva AJ, Storm JF (April 1999). "Functional and molecular aspects of voltage-gated K+ channel beta subunits". Annals of the New York Academy of Sciences. 868 (Apr 30): 344–55. Bibcode:1999NYASA.868..344P. doi:10.1111/j.1749-6632.1999.tb11296.x. PMID 10414304. S2CID 21621084.
  3. ^ Li Y, Um SY, McDonald TV (June 2006). "Voltage-gated potassium channels: regulation by accessory subunits". The Neuroscientist. 12 (3): 199–210. doi:10.1177/1073858406287717. PMID 16684966. S2CID 24418687.
  4. ^ Zhang M, Jiang M, Tseng GN (May 2001). "minK-related peptide 1 associates with Kv4.2 and modulates its gating function: potential role as beta subunit of cardiac transient outward channel?". Circulation Research. 88 (10): 1012–9. doi:10.1161/hh1001.090839. PMID 11375270.
  5. ^ McCrossan ZA, Abbott GW (November 2004). "The MinK-related peptides". Neuropharmacology. 47 (6): 787–821. doi:10.1016/j.neuropharm.2004.06.018. PMID 15527815. S2CID 41340789.
  6. ^ Anantharam A, Abbott GW (2005). Does hERG coassemble with a beta subunit? Evidence for roles of MinK and MiRP1. pp. 100–12, discussion 112–7, 155–8. doi:10.1002/047002142X.fmatter. ISBN 9780470021408. PMID 16050264. {{cite book}}: |journal= ignored (help)
  7. ^ Yellen G (September 2002). "The voltage-gated potassium channels and their relatives". Nature. 419 (6902): 35–42. doi:10.1038/nature00978. PMID 12214225. S2CID 4420877.
  8. ^ Long SB, Campbell EB, Mackinnon R (August 2005). "Crystal structure of a mammalian voltage-dependent Shaker family K+ channel". Science. 309 (5736): 897–903. Bibcode:2005Sci...309..897L. doi:10.1126/science.1116269. PMID 16002581. S2CID 6072007.
  9. ^ Lee SY, Lee A, Chen J, MacKinnon R (October 2005). "Structure of the KvAP voltage-dependent K+ channel and its dependence on the lipid membrane". Proceedings of the National Academy of Sciences of the United States of America. 102 (43): 15441–6. Bibcode:2005PNAS..10215441L. doi:10.1073/pnas.0507651102. PMC 1253646. PMID 16223877.
  10. ^ Antz C, Fakler B (August 1998). "Fast Inactivation of Voltage-Gated K(+) Channels: From Cartoon to Structure" (PDF). News in Physiological Sciences. 13 (4): 177–182. doi:10.1152/physiologyonline.1998.13.4.177. PMID 11390785.
  11. ^ Armstrong CM, Bezanilla F (April 1973). "Currents related to movement of the gating particles of the sodium channels". Nature. 242 (5398): 459–61. Bibcode:1973Natur.242..459A. doi:10.1038/242459a0. PMID 4700900. S2CID 4261606.
  12. ^ Murrell-Lagnado RD, Aldrich RW (December 1993). "Energetics of Shaker K channels block by inactivation peptides". The Journal of General Physiology. 102 (6): 977–1003. doi:10.1085/jgp.102.6.977. PMC 2229186. PMID 8133246.

External links Edit

  • Voltage-Gated+Potassium+Channels at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
  • "Voltage-Gated Potassium Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology.
  • Li B, Gallin WJ (January 2004). "VKCDB: voltage-gated potassium channel database". BMC Bioinformatics. 5: 3. doi:10.1186/1471-2105-5-3. PMC 317694. PMID 14715090.
  • "Voltage-gated potassium channel database (VKCDB)" at ualberta.ca
  • UMich Orientation of Proteins in Membranes families/superfamily-8 - Spatial positions of voltage gated potassium channels in membranes

August 26, 2023
voltage, gated, potassium, channel, vgkcs, transmembrane, channels, specific, potassium, sensitive, voltage, changes, cell, membrane, potential, during, action, potentials, they, play, crucial, role, returning, depolarized, cell, resting, state, eukaryotic, po. Voltage gated potassium channels VGKCs are transmembrane channels specific for potassium and sensitive to voltage changes in the cell s membrane potential During action potentials they play a crucial role in returning the depolarized cell to a resting state Eukaryotic potassium channelPotassium channel structure in a membrane like environment Calculated hydrocarbon boundaries of the lipid bilayer are indicated by red and blue dots IdentifiersSymbolIon transPfamPF00520InterProIPR005821SCOP21bl8 SCOPe SUPFAMTCDB1 A 1OPM superfamily8OPM protein2a79Membranome217Available protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summaryIon channel bacterial Potassium channel KcsA Calculated hydrocarbon boundaries of the lipid bilayer are indicated by red and blue dots IdentifiersSymbolIon trans 2PfamPF07885InterProIPR013099SCOP21bl8 SCOPe SUPFAMOPM protein1r3jAvailable protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summarySlow voltage gated potassium channel Potassium channel voltage dependent beta subunit KCNE IdentifiersSymbolISK ChannelPfamPF02060InterProIPR000369TCDB8 A 10Membranome218Available protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summaryKCNQ voltage gated potassium channelIdentifiersSymbolKCNQ channelPfamPF03520InterProIPR013821Available protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summaryKv2 voltage gated K channelIdentifiersSymbolKv2channelPfamPF03521InterProIPR003973Available protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summary Contents 1 Classification 1 1 Alpha subunits 1 1 1 Delayed rectifier 1 1 2 A type potassium channel 1 1 3 Outward rectifying 1 1 4 Inwardly rectifying 1 1 5 Slowly activating 1 1 6 Modifier silencer 1 2 Beta subunits 2 Animal research 3 Structure 4 Selectivity 5 Open and closed conformations 6 Pharmacology 7 See also 8 References 9 External linksClassification EditAlpha subunits Edit Alpha subunits form the actual conductance pore Based on sequence homology of the hydrophobic transmembrane cores the alpha subunits of voltage gated potassium channels are grouped into 12 classes These are labeled Kva1 12 1 The following is a list of the 40 known human voltage gated potassium channel alpha subunits grouped first according to function and then subgrouped according to the Kv sequence homology classification scheme Delayed rectifier Edit slowly inactivating or non inactivating Kva1 x Shaker related Kv1 1 KCNA1 Kv1 2 KCNA2 Kv1 3 KCNA3 Kv1 5 KCNA5 Kv1 6 KCNA6 Kv1 7 KCNA7 Kv1 8 KCNA10 Kva2 x Shab related Kv2 1 KCNB1 Kv2 2 KCNB2 Kva3 x Shaw related Kv3 1 KCNC1 Kv3 2 KCNC2 Kva7 x Kv7 1 KCNQ1 KvLQT1 Kv7 2 KCNQ2 Kv7 3 KCNQ3 Kv7 4 KCNQ4 Kv7 5 KCNQ5 Kva10 x Kv10 1 KCNH1 A type potassium channel Edit rapidly inactivating Kva1 x Shaker related Kv1 4 KCNA4 Kva4 x Shal related Kv4 1 KCND1 Kv4 2 KCND2 Kv4 3 KCND3 Outward rectifying Edit Kva10 x Kv10 2 KCNH5 Inwardly rectifying Edit Passes current more easily in the inward direction into the cell from outside Kva11 x ether a go go potassium channels Kv11 1 KCNH2 hERG Kv11 2 KCNH6 Kv11 3 KCNH7 Slowly activating Edit Kva12 x Kv12 1 KCNH8 Kv12 2 KCNH3 Kv12 3 KCNH4 Modifier silencer Edit Unable to form functional channels as homotetramers but instead heterotetramerize with Kva2 family members to form conductive channels Kva5 x Kv5 1 KCNF1 Kva6 x Kv6 1 KCNG1 Kv6 2 KCNG2 Kv6 3 KCNG3 Kv6 4 KCNG4 Kva8 x Kv8 1 KCNV1 Kv8 2 KCNV2 Kva9 x Kv9 1 KCNS1 Kv9 2 KCNS2 Kv9 3 KCNS3 Beta subunits Edit Beta subunits are auxiliary proteins that associate with alpha subunits sometimes in a a4b4 stoichiometry 2 These subunits do not conduct current on their own but rather modulate the activity of Kv channels 3 Kvb1 KCNAB1 Kvb2 KCNAB2 Kvb3 KCNAB3 minK 4 KCNE1 MiRP1 5 KCNE2 MiRP2 KCNE3 MiRP3 KCNE4 KCNE1 like KCNE1L KCNIP1 KCNIP1 KCNIP2 KCNIP2 KCNIP3 KCNIP3 KCNIP4 KCNIP4 Proteins minK and MiRP1 are putative hERG beta subunits 6 Animal research EditThe voltage gated K channels that provide the outward currents of action potentials have similarities to bacterial K channels These channels have been studied by X ray diffraction allowing determination of structural features at atomic resolution The function of these channels is explored by electrophysiological studies Genetic approaches include screening for behavioral changes in animals with mutations in K channel genes Such genetic methods allowed the genetic identification of the Shaker K channel gene in Drosophila before ion channel gene sequences were well known Study of the altered properties of voltage gated K channel proteins produced by mutated genes has helped reveal the functional roles of K channel protein domains and even individual amino acids within their structures Structure EditTypically vertebrate voltage gated K channels are tetramers of four identical subunits arranged as a ring each contributing to the wall of the trans membrane K pore Each subunit is composed of six membrane spanning hydrophobic a helical sequences as well as a voltage sensor in S4 The intracellular side of the membrane contains both amino and carboxy termini 7 The high resolution crystallographic structure of the rat Kva1 2 b2 channel has recently been solved Protein Databank Accession Number 2A79 8 and then refined in a lipid membrane like environment PDB 2r9r Selectivity EditMain article Potassium channel Selectivity filter Voltage gated K channels are selective for K over other cations such as Na There is a selectivity filter at the narrowest part of the transmembrane pore Channel mutation studies have revealed the parts of the subunits that are essential for ion selectivity They include the amino acid sequence Thr Val Gly Tyr Gly or Thr Val Gly Phe Gly typical to the selectivity filter of voltage gated K channels As K passes through the pore interactions between potassium ions and water molecules are prevented and the K interacts with specific atomic components of the Thr Val Gly YF Gly sequences from the four channel subunits 1 It may seem counterintuitive that a channel should allow potassium ions but not the smaller sodium ions through However in an aqueous environment potassium and sodium cations are solvated by water molecules When moving through the selectivity filter of the potassium channel the water K interactions are replaced by interactions between K and carbonyl groups of the channel protein The diameter of the selectivity filter is ideal for the potassium cation but too big for the smaller sodium cation Hence the potassium cations are well solvated by the protein carbonyl groups but these same carbonyl groups are too far apart to adequately solvate the sodium cation Hence the passage of potassium cations through this selectivity filter is strongly favored over sodium cations Open and closed conformations EditThe structure of the mammalian voltage gated K channel has been used to explain its ability to respond to the voltage across the membrane Upon opening of the channel conformational changes in the voltage sensor domains VSD result in the transfer of 12 13 elementary charges across the membrane electric field This charge transfer is measured as a transient capacitive current that precedes opening of the channel Several charged residues of the VSD in particular four arginine residues located regularly at every third position on the S4 segment are known to move across the transmembrane field and contribute to the gating charge The position of these arginines known as gating arginines are highly conserved in all voltage gated potassium sodium or calcium channels However the extent of their movement and their displacement across the transmembrane potential has been subject to extensive debate 9 Specific domains of the channel subunits have been identified that are responsible for voltage sensing and converting between the open and closed conformations of the channel There are at least two closed conformations In the first the channel can open if the membrane potential becomes more positive This type of gating is mediated by a voltage sensing domain that consists of the S4 alpha helix that contains 6 7 positive charges Changes in membrane potential cause this alpha helix to move in the lipid bilayer This movement in turn results in a conformational change in the adjacent S5 S6 helices that form the channel pore and cause this pore to open or close In the second N type inactivation voltage gated K channels inactivate after opening entering a distinctive closed conformation In this inactivated conformation the channel cannot open even if the transmembrane voltage is favorable The amino terminal domain of the K channel or an auxiliary protein can mediate N type inactivation The mechanism of this type of inactivation has been described as a ball and chain model where the N terminus of the protein forms a ball that is tethered to the rest of the protein through a loop the chain 10 The tethered ball blocks the inner porehole preventing ion movement through the channel 11 12 Pharmacology EditThis section needs expansion You can help by adding to it May 2019 For blockers and activators of voltage gated potassium channels see potassium channel blocker and potassium channel opener See also EditIon channel Ion channel family Potassium channel tetramerisation domain Voltage gated potassium channel database 2004 References Edit Gutman GA Chandy KG Grissmer S Lazdunski M McKinnon D Pardo LA Robertson GA Rudy B Sanguinetti MC Stuhmer W Wang X December 2005 International Union of Pharmacology LIII Nomenclature and molecular relationships of voltage gated potassium channels Pharmacological Reviews 57 4 473 508 doi 10 1124 pr 57 4 10 PMID 16382104 S2CID 219195192 Pongs O Leicher T Berger M Roeper J Bahring R Wray D Giese KP Silva AJ Storm JF April 1999 Functional and molecular aspects of voltage gated K channel beta subunits Annals of the New York Academy of Sciences 868 Apr 30 344 55 Bibcode 1999NYASA 868 344P doi 10 1111 j 1749 6632 1999 tb11296 x PMID 10414304 S2CID 21621084 Li Y Um SY McDonald TV June 2006 Voltage gated potassium channels regulation by accessory subunits The Neuroscientist 12 3 199 210 doi 10 1177 1073858406287717 PMID 16684966 S2CID 24418687 Zhang M Jiang M Tseng GN May 2001 minK related peptide 1 associates with Kv4 2 and modulates its gating function potential role as beta subunit of cardiac transient outward channel Circulation Research 88 10 1012 9 doi 10 1161 hh1001 090839 PMID 11375270 McCrossan ZA Abbott GW November 2004 The MinK related peptides Neuropharmacology 47 6 787 821 doi 10 1016 j neuropharm 2004 06 018 PMID 15527815 S2CID 41340789 Anantharam A Abbott GW 2005 Does hERG coassemble with a beta subunit Evidence for roles of MinK and MiRP1 pp 100 12 discussion 112 7 155 8 doi 10 1002 047002142X fmatter ISBN 9780470021408 PMID 16050264 a href Template Cite book html title Template Cite book cite book a journal ignored help Yellen G September 2002 The voltage gated potassium channels and their relatives Nature 419 6902 35 42 doi 10 1038 nature00978 PMID 12214225 S2CID 4420877 Long SB Campbell EB Mackinnon R August 2005 Crystal structure of a mammalian voltage dependent Shaker family K channel Science 309 5736 897 903 Bibcode 2005Sci 309 897L doi 10 1126 science 1116269 PMID 16002581 S2CID 6072007 Lee SY Lee A Chen J MacKinnon R October 2005 Structure of the KvAP voltage dependent K channel and its dependence on the lipid membrane Proceedings of the National Academy of Sciences of the United States of America 102 43 15441 6 Bibcode 2005PNAS 10215441L doi 10 1073 pnas 0507651102 PMC 1253646 PMID 16223877 Antz C Fakler B August 1998 Fast Inactivation of Voltage Gated K Channels From Cartoon to Structure PDF News in Physiological Sciences 13 4 177 182 doi 10 1152 physiologyonline 1998 13 4 177 PMID 11390785 Armstrong CM Bezanilla F April 1973 Currents related to movement of the gating particles of the sodium channels Nature 242 5398 459 61 Bibcode 1973Natur 242 459A doi 10 1038 242459a0 PMID 4700900 S2CID 4261606 Murrell Lagnado RD Aldrich RW December 1993 Energetics of Shaker K channels block by inactivation peptides The Journal of General Physiology 102 6 977 1003 doi 10 1085 jgp 102 6 977 PMC 2229186 PMID 8133246 External links EditVoltage Gated Potassium Channels at the U S National Library of Medicine Medical Subject Headings MeSH Voltage Gated Potassium Channels IUPHAR Database of Receptors and Ion Channels International Union of Basic and Clinical Pharmacology Li B Gallin WJ January 2004 VKCDB voltage gated potassium channel database BMC Bioinformatics 5 3 doi 10 1186 1471 2105 5 3 PMC 317694 PMID 14715090 Voltage gated potassium channel database VKCDB at ualberta ca UMich Orientation of Proteins in Membranes families superfamily 8 Spatial positions of voltage gated potassium channels in membranes Retrieved from https en wikipedia org w index php title Voltage gated potassium channel amp oldid 1080832747, wikipedia, wiki, book, books, library,

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