P58498 (KAX64_PANIM) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin alpha-KTx 6.4 Alternative name(s): Potassium channel-blocking toxin 4 Short name=Pi-4 Short name=Pi4
Organism	Pandinus imperator (Emperor scorpion)
Taxonomic identifier	55084 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Ecdysozoa › Panarthropoda › Arthropoda › Chelicerata › Arachnida › Scorpiones › Iurida › Scorpionoidea › Scorpionidae › Scorpioninae › Pandinus

Protein attributes

Sequence length	38 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Potently, completely and reversibly blocks voltage-gated potassium channel Kv1.2/KCNA2 and Shaker B (Sh). Also blocks small conductance (SK) calcium-activated potassium channel (KCNN). Ref.2
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Domain	Has the structural arrangement of an alpha-helix connected to a beta-sheet by disulfide bonds (CSalpha/beta).
Toxic dose	LD50 is 10 µg/kg by intracerebroventricular injection into mice. Ref.2
Miscellaneous	This toxin has no effect on voltage-gated potassium channel Kv1.1/KCNA1 and Kv1.3/KCNA3 (Ref.2).
Sequence similarities	Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 6 subfamily.

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ion channel impairing toxin Potassium channel inhibitor Toxin
PTM	Disulfide bond
Technical term	3D-structure Direct protein sequencing
Gene Ontology (GO)
Biological_process	pathogenesis Inferred from electronic annotation. Source: InterPro
Cellular_component	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular_function	potassium channel inhibitor activity Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Peptide

1 – 38

38

Potassium channel toxin alpha-KTx 6.4

PRO_0000044913

Sites

Site

10

1

Important for the interaction with Kv1.2/KCNA2 channel

Site

19

1

Important for the interaction with Kv1.2/KCNA2 channel

Site

26

1

Basic residue of the functional dyad, important for the interaction with Kv1.2/KCNA2 channel

Site

28

1

Important for the interaction with Kv1.2/KCNA2 channel

Site

30

1

Important for the interaction with Kv1.2/KCNA2 channel

Site

33

1

Important for the interaction with Kv1.2/KCNA2 channel

Site

35

1

Aromatic residue of the functional dyad, important for the interaction with Kv1.2/KCNA2 channel

Amino acid modifications

Disulfide bond

6 ↔ 27

Ref.2 Ref.3

Disulfide bond

12 ↔ 32

Ref.2 Ref.3

Disulfide bond

16 ↔ 34

Ref.2 Ref.3

Disulfide bond

22 ↔ 37

Ref.2 Ref.3

Secondary structure

1

.

.

.

.

.

.

.

38

Helix Strand Turn

Details...

Helix

10 – 20

11

Beta strand

25 – 28

4

Beta strand

31 – 34

4

Sequences

	Sequence		Length	Mass (Da)
	P58498 [UniParc]. Last modified December 19, 2001. Version 1. Checksum: 1C1F402B8DF2EEFF	FASTA	38	4,188
	10 20 30 IEAIRCGGSR DCYRPCQKRT GCPNAKCINK TCKCYGCS

References

[1]	"Two similar peptides from the venom of the scorpion Pandinus imperator, one highly effective blocker and the other inactive on K+ channels." Olamendi-Portugal T., Gomez-Lagunas F., Gurrola G.B., Possani L.D. Toxicon 36:759-770(1998) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE. Tissue: Venom.
[2]	"Synthesis and characterization of Pi4, a scorpion toxin from Pandinus imperator that acts on K+ channels." M'Barek S., Mosbah A., Sandoz G., Fajloun Z., Olamendi-Portugal T., Rochat H., Sampieri F., Guijarro J.I., Mansuelle P., Delepierre M., De Waard M., Sabatier J.-M. Eur. J. Biochem. 270:3583-3592(2003) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, TOXIN TARGET, LETHAL DOSE, DISULFIDE BONDS, SYNTHESIS.
[3]	"Solution structure of Pi4, a short four-disulfide-bridged scorpion toxin specific of potassium channels." Guijarro J.I., M'Barek S., Gomez-Lagunas F., Garnier D., Rochat H., Sabatier J.-M., Possani L.D., Delepierre M. Protein Sci. 12:1844-1854(2003) [PubMed] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS, SYNTHESIS.
[4]	Erratum Guijarro J.I., M'Barek S., Gomez-Lagunas F., Garnier D., Rochat H., Sabatier J.-M., Possani L., Delepierre M. Protein Sci. 12:2651-2651(2003)

Cross-references

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1N8M	NMR	-	A	1-38	[»]

ProteinModelPortal

P58498.

SMR

P58498. Positions 1-38.

ModBase

Search...

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Family and domain databases

Gene3D

3.30.30.10. 1 hit.

InterPro

IPR003614. Scorpion_toxin-like.
IPR001947. Scorpion_toxinS_K_inh.
[Graphical view]

Pfam

PF00451. Toxin_2. 1 hit.
[Graphical view]

ProDom

PD003586. Scorpion_toxinS. 1 hit.
[Graphical view] [Entries sharing at least one domain]

SUPFAM

SSF57095. SSF57095. 1 hit.

PROSITE

PS01138. SCORP_SHORT_TOXIN. 1 hit.
[Graphical view]

ProtoNet

Search...

Other

EvolutionaryTrace

P58498.

Entry information

Entry name

KAX64_PANIM

Accession

Primary (citable) accession number: P58498

Entry history

Integrated into UniProtKB/Swiss-Prot:	December 19, 2001
Last sequence update:	December 19, 2001
Last modified:	May 1, 2013
This is version 60 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program