Reviewed, UniProtKB/Swiss-Prot P56219 (KAX42_TITSE)

Names and origin

Protein names	Recommended name:     Potassium channel toxin alpha-KTx 4.2 Alternative name(s):     Neurotoxin Ts-kappa       Short name=TsKapa       Short name=TsK
Organism	Tityus serrulatus (Brazilian scorpion)
Taxonomic identifier	6887 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Tityus

Protein attributes

Sequence length	57 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Blocker for small-conductance calcium-activated potassium channels.
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 4 subfamily.

Ontologies

Keywords
Cellular component	Secreted
Domain	Signal
Molecular function	Ionic channel inhibitor Neurotoxin 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

Signal peptide

1 – 20

20

Potential

Propeptide

21 – 22

2

Removed by a carboxypeptidase

PRO_0000035329

Chain

23 – 57

35

Potassium channel toxin alpha-KTx 4.2

PRO_0000035330

Amino acid modifications

Disulfide bond

29 ↔ 50

Ref.2

Disulfide bond

35 ↔ 55

Ref.2

Disulfide bond

39 ↔ 57

Ref.2

Secondary structure

1

.

.

.

.

.

.

.

.

.

.

.

57

Helix Strand Turn

Details...

Beta strand

30 – 32

3

Helix

36 – 42

7

Beta strand

44 – 46

3

Beta strand

49 – 51

3

Beta strand

54 – 56

3

Sequences

	Sequence		Length	Mass (Da)
	P56219-1 [UniParc]. Last modified September 9, 2003. Version 2. Checksum: 044A29EDE4512A18	FASTA	57	6,392
	10 20 30 40 50 MKVLYGILII FILCSMFYLS QEVVIGQRCY RSPDCYSACK KLVGKATGKC TNGRCDC

References

[1]	"Characterization of a new peptide from Tityus serrulatus scorpion venom which is a ligand of the apamin-binding site." Legros C., Oughideni R., Darbon H., Rochat H., Bougis P.E., Martin-Eauclaire M.-F. FEBS Lett. 390:81-84(1996) [PubMed: 8706835] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 23-57. Tissue: Venom and Venom gland.
[2]	"Solution structure of TsKapa, a charybdotoxin-like scorpion toxin from Tityus serrulatus with high affinity for apamin-sensitive Ca(2+)-activated K+ channels." Blanc E., Lecomte C., Martin-Eauclaire M.-F., van Rietschoten J., Sabatier J.-M., Darbon H. Proteins 29:359-369(1997) [PubMed: 9365990] [Abstract] Cited for: STRUCTURE BY NMR OF 23-57, DISULFIDE BONDS.

Cross-references

Sequence databases

PIR

S70473.

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1TSK	NMR	-	A	23-57	[»]

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

KAX42_TITSE

Accession

Primary (citable) accession number: P56219

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 15, 1998
Last sequence update:	September 9, 2003
Last modified:	June 16, 2009
This is version 69 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)