Reviewed, UniProtKB/Swiss-Prot P59867 (KAX63_HETSP)

Names and origin

Protein names	Recommended name:     Potassium channel toxin alpha-KTx 6.3 Alternative name(s):     Neurotoxin HsTX1
Organism	Heterometrus spinifer (Asia giant forest scorpion) (Malaysian black scorpion)
Taxonomic identifier	118530 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Iurida › Scorpionoidea › Scorpionidae › Scorpioninae › Heterometrus

Protein attributes

Sequence length	34 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 channels Kv1.1 (KCNA1) and Kv1.3 (KCNA3). Mildly blocks intermediate (IK) conductance calcium-activated potassium channels and is inactive on Kv1.2 (KCNA2) channels. Ref.1 Ref.2
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Sequence similarities	Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 6 subfamily.
Mass spectrometry	Molecular mass is 3815.63 Da from positions 1 - 34. Determined by MALDI. Ref.1

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ionic channel inhibitor Neurotoxin Potassium channel inhibitor Toxin
PTM	Amidation 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 – 34

34

Potassium channel toxin alpha-KTx 6.3

PRO_0000044908

Sites

Site

21

1

Important for activity

Site

23

1

Critical for activity

Site

25

1

Important for activity

Site

26

1

Important for activity

Site

33

1

Important for activity

Amino acid modifications

Modified residue

34

1

Cysteine amide

Disulfide bond

3 ↔ 24

Ref.1 Ref.3 Ref.4

Disulfide bond

9 ↔ 29

Ref.1 Ref.3 Ref.4

Disulfide bond

13 ↔ 31

Ref.1 Ref.3 Ref.4

Disulfide bond

19 ↔ 34

Ref.1 Ref.3 Ref.4

Secondary structure

1

.

.

.

.

.

.

.

.

34

Helix Strand Turn

Details...

Helix

6 – 9

4

Helix

10 – 16

7

Beta strand

22 – 27

6

Beta strand

29 – 31

3

Sequences

	Sequence		Length	Mass (Da)
	P59867-1 [UniParc]. Last modified September 26, 2003. Version 1. Checksum: 6078F957A4FDF39A	FASTA	34	3,828
	10 20 30 ASCRTPKDCA DPCRKETGCP YGKCMNRKCK CNRC

References

[1]	"A four-disulphide-bridged toxin, with high affinity towards voltage-gated K+ channels, isolated from Heterometrus spinnifer (Scorpionidae) venom." Lebrun B., Romi-Lebrun R., Martin-Eauclaire M.-F., Yasuda A., Ishiguro M., Oyama Y., Pongs O., Nakajima T. Biochem. J. 328:321-327(1997) [PubMed: 9359871] [Abstract] Cited for: PROTEIN SEQUENCE, FUNCTION, MASS SPECTROMETRY, DISULFIDE BONDS, AMIDATION. Tissue: Venom.
[2]	"Evidence for domain-specific recognition of SK and Kv channels by MTX and HsTx1 scorpion toxins." Regaya I., Beeton C., Ferrat G., Andreotti N., Darbon H., De Waard M., Sabatier J.M. J. Biol. Chem. 279:55690-55696(2004) [PubMed: 15498765] [Abstract] Cited for: FUNCTION, STRUCTURE BY NMR OF A MAUROTOXIN-HSTX1 CHIMERA.
[3]	"Structural and functional consequences of the presence of a fourth disulfide bridge in the scorpion short toxins: solution structure of the potassium channel inhibitor HsTX1." Savarin P., Romi-Lebrun R., Zinn-Justin S., Lebrun B., Nakajima T., Gilquin B., Menez A. Protein Sci. 8:2672-2685(1999) [PubMed: 10631983] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.
[4]	"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: 16247791] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.

Cross-references

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1QUZ	NMR	-	A	1-34	[»]
1WPD	NMR	-	A	7-34	[»]
1Y2P	NMR	-	A	1-34	[»]

ModBase

Search...

Family and domain databases

InterPro

IPR001947. Scorpion_toxinS.
[Graphical view]

Pfam

PF00451. Toxin_2. 1 hit.
[Graphical view]

PRINTS

PR00286. CHARYBDTOXIN.

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

KAX63_HETSP

Accession

Primary (citable) accession number: P59867

Entry history

Integrated into UniProtKB/Swiss-Prot:	September 26, 2003
Last sequence update:	September 26, 2003
Last modified:	June 16, 2009
This is version 42 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)