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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

GO - Biological processi

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

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...

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: September 7, 2016
This is version 91 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

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 one 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.