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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

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

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sitei5Part of the basic ring which may anchor to the external vestibule of the K(+) channel1
Sitei12Part of the basic ring which may anchor to the external vestibule of the K(+) channel1
Sitei24Basic residue of the functional dyad1
Sitei28Part of the basic ring which may anchor to the external vestibule of the K(+) channel1
Sitei31Part of the basic ring which may anchor to the external vestibule of the K(+) channel1
Sitei33Aromatic residue of the functional dyad1

GO - Molecular functioni

GO - Biological processi

Keywordsi

Molecular functionCalcium-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

Keywords - Cellular componenti

Secreted

Pathology & Biotechi

Toxic dosei

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

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi5R → 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 Publication1
Mutagenesisi12R → A: 51-fold decrease in inhibiting Kv1.2/KCNA2 channels; when associated with A-5. 1 Publication1
Mutagenesisi24K → 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 Publication1
Mutagenesisi31K → 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 Publication1
Mutagenesisi33Y → 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 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
PeptideiPRO_00000449121 – 35Potassium channel toxin alpha-KTx 6.1Add BLAST35

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
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

135
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Turni6 – 10Combined sources5
Helixi11 – 17Combined sources7
Beta strandi24 – 26Combined sources3
Beta strandi29 – 31Combined sources3

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1WZ5NMR-A1-35[»]
ProteinModelPortaliQ10726.
SMRiQ10726.
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.
InterProiView protein in InterPro
IPR003614. Scorpion_toxin-like.
IPR001947. Scorpion_toxinS_K_inh.
PfamiView protein in Pfam
PF00451. Toxin_2. 1 hit.
ProDomiView protein in ProDom or Entries sharing at least one domain
PD003586. Scorpion_toxinS. 1 hit.
SUPFAMiSSF57095. SSF57095. 1 hit.
PROSITEiView protein in PROSITE
PS01138. SCORP_SHORT_TOXIN. 1 hit.

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.

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.

Entry informationi

Entry nameiKAX61_PANIM
AccessioniPrimary (citable) accession number: Q10726
Entry historyiIntegrated into UniProtKB/Swiss-Prot: October 1, 1996
Last sequence update: October 1, 1996
Last modified: November 30, 2016
This is version 93 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programAnimal Toxin Annotation Program

Miscellaneousi

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