Reviewed, UniProtKB/Swiss-Prot P59925 (KAX43_TITDI)

Names and origin

Protein names	Recommended name:     Potassium channel toxin alpha-KTx 4.3 Alternative name(s):     Toxin TdK1
Organism	Tityus discrepans (Venezuelan scorpion)
Taxonomic identifier	57059 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Tityus

Protein attributes

Sequence length	37 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Blocks reversibly Shaker B 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.
Mass spectrometry	Molecular mass is 3816.8 Da from positions 1 - 37. Determined by MALDI. Ref.1 Molecular mass is 3816 Da from positions 1 - 37. Determined by ESI. Ref.2

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ionic channel inhibitor Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond
Technical term	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 – 37	37	Potassium channel toxin alpha-KTx 4.3		PRO_0000044922
Regions
	Region	26 – 33	8	Interaction with Ca(2+)-activated K(+) channels Potential
Amino acid modifications
	Disulfide bond	7 ↔ 28		By similarity
	Disulfide bond	13 ↔ 33		By similarity
	Disulfide bond	17 ↔ 35		By similarity

Sequences

	Sequence		Length	Mass (Da)
	P59925-1 [UniParc]. Last modified October 24, 2003. Version 1. Checksum: 6DC2FA311C38542F	FASTA	37	3,826
	10 20 30 VFINVKCTGS KQCLPACKAA VGKAAGKCMN GKCKCYT

References

[1]	"A novel K+ channel blocking toxin from Tityus discrepans scorpion venom." D'Suze G., Zamudio F., Gomez-Lagunas F., Possani L.D. FEBS Lett. 456:146-148(1999) [PubMed: 10452547] [Abstract] Cited for: PROTEIN SEQUENCE, MASS SPECTROMETRY. Tissue: Venom.
[2]	"Proteomic analysis of Tityus discrepans scorpion venom and amino acid sequence of novel toxins." Batista C.V.F., D'Suze G., Gomez-Lagunas F., Zamudio F.Z., Encarnacion S., Sevcik C., Possani L.D. Proteomics 6:3718-3727(2006) [PubMed: 16705749] [Abstract] Cited for: PROTEIN SEQUENCE OF 1-10, MASS SPECTROMETRY.

Cross-references

3D structure databases
ModBase	Search...
Family and domain databases
InterPro	IPR001947. Scorpion_toxinS. [Graphical view]
Pfam	PF00451. Toxin_2. 1 hit. [Graphical view]
PRINTS	PR00286. CHARYBDTOXIN.
PROSITE	PS01138. SCORP_SHORT_TOXIN. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

KAX43_TITDI

Accession

Primary (citable) accession number: P59925

Entry history

Integrated into UniProtKB/Swiss-Prot:	October 24, 2003
Last sequence update:	October 24, 2003
Last modified:	November 24, 2009
This is version 36 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)