Reviewed, UniProtKB/Swiss-Prot P58498 (KAX64_PANIM)

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	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Iurida › Scorpionoidea › Scorpionidae › Scorpioninae › Pandinus

Protein attributes

Sequence length	38 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Potently blocks voltage-gated potassium channel Kv1.2 (KCNA2) and Shaker B (Sh) (complete and reversible), whereas has no effect on voltage-gated potassium channel Kv1.1 (KCNA1) and Kv1.3 (KCNA3). Also blocks small conductance calcium-activated potassium channel (KCNN). Ref.2
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Toxic dose	LD50 is 10 µg/kg by intracerebroventricular injection into mice. 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	Ionic channel inhibitor 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: UniProtKB-KW
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 KCNA2 channel

Site

19

1

Important for the interaction with KCNA2 channel

Site

26

1

Important for the interaction with KCNA2 channel

Site

28

1

Important for the interaction with KCNA2 channel

Site

30

1

Important for the interaction with KCNA2 channel

Site

33

1

Important for the interaction with KCNA2 channel

Site

35

1

Important for the interaction with 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)
	P58498-1 [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: 9655636] [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: 12919322] [Abstract] Cited for: FUNCTION, 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: 12930984] [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

PDBPDBe

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

ModBase

Search...

Family and domain databases

InterPro

IPR001947. Scorpion_toxinS.
[Graphical view]

Pfam

PF00451. Toxin_2. 1 hit.
[Graphical view]

ProDom

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

PROSITE

PS01138. SCORP_SHORT_TOXIN. 1 hit.
[Graphical view]

ProtoNet

Search...

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:	June 16, 2009
This is version 49 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)