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Protein

Potassium channel toxin alpha-KTx 6.1

Gene
N/A
Organism
Pandinus imperator (Emperor scorpion)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Potently and reversibly inhibits the insect voltage-gated Shaker (Sh) potassium channel (isoform alpha (B)), the mammalian voltage-gated potassium channels Kv1.2/KCNA2. Its effect on Kv1.3/KCNA3 is controversial, since this channel is voltage-independently inhibited in PubMed:9464266, but is not affected in PubMed:10931199. Furthermore, this toxin competes with apamin (a small conductance calcium-activated potassium channel inhibitor) for binding onto rat brain synaptosomes.4 Publications

Sites

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sitei5 – 51Part of the basic ring which may anchor to the external vestibule of the K(+) channel
Sitei12 – 121Part of the basic ring which may anchor to the external vestibule of the K(+) channel
Sitei24 – 241Basic residue of the functional dyad
Sitei28 – 281Part of the basic ring which may anchor to the external vestibule of the K(+) channel
Sitei31 – 311Part of the basic ring which may anchor to the external vestibule of the K(+) channel
Sitei33 – 331Aromatic residue of the functional dyad

GO - Molecular functioni

  1. ion channel inhibitor activity Source: InterPro

GO - Biological processi

  1. defense response Source: InterPro
  2. pathogenesis Source: InterPro
Complete GO annotation...

Keywords - Molecular functioni

Calcium-activated potassium channel impairing toxin, Ion channel impairing toxin, Neurotoxin, Potassium channel impairing toxin, Toxin, Voltage-gated potassium channel impairing toxin

Names & Taxonomyi

Protein namesi
Recommended name:
Potassium channel toxin alpha-KTx 6.1
Alternative name(s):
PiTX-K-gamma
Potassium channel-blocking toxin 1
Short name:
Pi-1
Short name:
Pi1
OrganismiPandinus imperator (Emperor scorpion)
Taxonomic identifieri55084 [NCBI]
Taxonomic lineageiEukaryotaMetazoaEcdysozoaArthropodaChelicerataArachnidaScorpionesIuridaScorpionoideaScorpionidaeScorpioninaePandinus

Subcellular locationi

GO - Cellular componenti

  1. extracellular region Source: UniProtKB-SubCell
Complete GO annotation...

Keywords - Cellular componenti

Secreted

Pathology & Biotechi

Toxic dosei

LD50 is 10 µg/kg by intraperitoneal injection into mice.1 Publication

Mutagenesis

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Mutagenesisi5 – 51R → A: 51-fold decrease in inhibiting Kv1.2/KCNA2 channels; when associated with A-12. 479-fold decrease in inhibiting Kv1.2/KCNA2 channels; when associated with A-31. 1 Publication
Mutagenesisi12 – 121R → A: 51-fold decrease in inhibiting Kv1.2/KCNA2 channels; when associated with A-5. 1 Publication
Mutagenesisi24 – 241K → A: 500-fold decrease in LD(50), 600-fold decrease of potency in competition assay with apamin, and 17000-fold decrease in inhibiting Kv1.2/KCNA2 channels; when associated with A-33. 1 Publication
Mutagenesisi31 – 311K → A: 294-fold decrease in inhibiting Kv1.2/KCNA2 channels. 479-fold decrease in inhibiting Kv1.2/KCNA2 channels; when associated with A-5. 1 Publication
Mutagenesisi33 – 331Y → A: 500-fold decrease in LD(50), 600-fold decrease of potency in competition assay with apamin, and 17,000-fold decrease in inhibiting Kv1.2/KCNA2 channels; when associated with A-24. 1 Publication

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Peptidei1 – 3535Potassium channel toxin alpha-KTx 6.1PRO_0000044912Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Disulfide bondi4 ↔ 251 Publication
Disulfide bondi10 ↔ 301 Publication
Disulfide bondi14 ↔ 321 Publication
Disulfide bondi20 ↔ 351 Publication

Keywords - PTMi

Disulfide bond

Expressioni

Tissue specificityi

Expressed by the venom gland.

Structurei

Secondary structure

1
35
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Turni6 – 105Combined sources
Helixi11 – 177Combined sources
Beta strandi24 – 263Combined sources
Beta strandi29 – 313Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
1WZ5NMR-A1-35[»]
ProteinModelPortaliQ10726.
SMRiQ10726. Positions 1-34.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiQ10726.

Family & Domainsi

Domaini

Has the structural arrangement of an alpha-helix connected to a beta-sheet by disulfide bonds (CSalpha/beta).
The alpha-helical domain may play a key role in the recognition of SK channels.
The beta-sheet structure may be involved in bioactivity on Kv channels.

Sequence similaritiesi

Family and domain databases

Gene3Di3.30.30.10. 1 hit.
InterProiIPR003614. Scorpion_toxin-like.
IPR001947. Scorpion_toxinS_K_inh.
[Graphical view]
PfamiPF00451. Toxin_2. 1 hit.
[Graphical view]
ProDomiPD003586. Scorpion_toxinS. 1 hit.
[Graphical view] [Entries sharing at least one domain]
SUPFAMiSSF57095. SSF57095. 1 hit.
PROSITEiPS01138. SCORP_SHORT_TOXIN. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Q10726-1 [UniParc]FASTAAdd to Basket

« Hide

        10         20         30 
LVKCRGTSDC GRPCQQQTGC PNSKCINRMC KCYGC
Length:35
Mass (Da):3,843
Last modified:October 1, 1996 - v1
Checksum:i208001C82B2C9800
GO

Sequence databases

PIRiS69599.

Cross-referencesi

Sequence databases

PIRiS69599.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
1WZ5NMR-A1-35[»]
ProteinModelPortaliQ10726.
SMRiQ10726. Positions 1-34.
ModBaseiSearch...
MobiDBiSearch...

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Miscellaneous databases

EvolutionaryTraceiQ10726.

Family and domain databases

Gene3Di3.30.30.10. 1 hit.
InterProiIPR003614. Scorpion_toxin-like.
IPR001947. Scorpion_toxinS_K_inh.
[Graphical view]
PfamiPF00451. Toxin_2. 1 hit.
[Graphical view]
ProDomiPD003586. Scorpion_toxinS. 1 hit.
[Graphical view] [Entries sharing at least one domain]
SUPFAMiSSF57095. SSF57095. 1 hit.
PROSITEiPS01138. SCORP_SHORT_TOXIN. 1 hit.
[Graphical view]
ProtoNetiSearch...

Publicationsi

  1. "A novel structural class of K+-channel blocking toxin from the scorpion Pandinus imperator."
    Olamendi-Portugal T., Gomez-Lagunas F., Gurrola G.B., Possani L.D.
    Biochem. J. 315:977-981(1996) [PubMed] [Europe PMC] [Abstract]
    Cited for: PROTEIN SEQUENCE, FUNCTION, TOXIN TARGET, DISULFIDE BONDS.
    Tissue: Venom.
  2. "Three new toxins from the scorpion Pandinus imperator selectively block certain voltage-gated K+ channels."
    Rogowski R.S., Collins J.H., O'Neill T.J., Gustafson T.A., Werkman T.R., Rogawski M.A., Tenenholz T.C., Weber D.J., Blaustein M.P.
    Mol. Pharmacol. 50:1167-1177(1996) [PubMed] [Europe PMC] [Abstract]
    Cited for: PROTEIN SEQUENCE.
    Tissue: Venom.
  3. "Block of ShakerB K+ channels by Pi1, a novel class of scorpion toxin."
    Gomez-Lagunas F., Olamendi-Portugal T., Possani L.D.
    FEBS Lett. 400:197-200(1997) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, TOXIN TARGET.
  4. "Pandinus imperator scorpion venom blocks voltage-gated K+ channels in human lymphocytes."
    Peter M. Jr., Varga Z., Panyi G., Bene L., Damjanovich S., Pieri C., Possani L.D., Gaspar R. Jr.
    Biochem. Biophys. Res. Commun. 242:621-625(1998) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, TOXIN TARGET.
  5. "Chemical synthesis and characterization of Pi1, a scorpion toxin from Pandinus imperator active on K+ channels."
    Fajloun Z., Carlier E., Lecomte C., Geib S., Di Luccio E., Bichet D., Mabrouk K., Rochat H., De Waard M., Sabatier J.M.
    Eur. J. Biochem. 267:5149-5155(2000) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, TOXIN TARGET, LETHAL DOSE, SYNTHESIS.
  6. "The 'functional' dyad of scorpion toxin Pi1 is not itself a prerequisite for toxin binding to the voltage-gated Kv1.2 potassium channels."
    Mouhat S., Mosbah A., Visan V., Wulff H., Delepierre M., Darbon H., Grissmer S., De Waard M., Sabatier J.M.
    Biochem. J. 377:25-36(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: MUTAGENESIS OF ARG-5; ARG-12; LYS-24; LYS-31 AND TYR-33, SITES.
  7. "A novel potassium channel blocking toxin from the scorpion Pandinus imperator: a 1H NMR analysis using a nano-NMR probe."
    Delepierre M., Prochnicka-Chalufour A., Possani L.D.
    Biochemistry 36:2649-2658(1997) [PubMed] [Europe PMC] [Abstract]
    Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.
  8. "The impact of the fourth disulfide bridge in scorpion toxins of the alpha-KTx6 subfamily."
    Carrega L., Mosbah A., Ferrat G., Beeton C., Andreotti N., Mansuelle P., Darbon H., De Waard M., Sabatier J.M.
    Proteins 61:1010-1023(2005) [PubMed] [Europe PMC] [Abstract]
    Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.

Entry informationi

Entry nameiKAX61_PANIM
AccessioniPrimary (citable) accession number: Q10726
Entry historyi
Integrated into UniProtKB/Swiss-Prot: October 1, 1996
Last sequence update: October 1, 1996
Last modified: January 7, 2015
This is version 87 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programAnimal Toxin Annotation Program

Miscellaneousi

Miscellaneous

Pi1 analog that is synthesized with a phosphorylation at Tyr-33 (P-Pi1) suffers a 200-fold decrease in LD50, a 200-fold decrease of potency in competition assay with apamin, and a 58-fold decrease in inhibiting Kv1.2/KCNA2 channels.
This toxin has no effect on Kv1.1/KCNA1.1 Publication

Keywords - Technical termi

3D-structure, Direct protein sequencing

Documents

  1. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  2. Scorpion potassium channel toxins
    Nomenclature of scorpion potassium channel toxins and list of entries
  3. SIMILARITY comments
    Index of protein domains and families

External Data

Dasty 3

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into Uniref entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.