Reviewed, UniProtKB/Swiss-Prot P24663 (KAX13_MESTA)

Names and origin

Protein names	Recommended name:     Potassium channel toxin alpha-KTx 1.3 Alternative name(s):     Iberiotoxin       Short name=IbTx
Organism	Mesobuthus tamulus (Eastern Indian scorpion) (Buthus tamulus)
Taxonomic identifier	34647 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Mesobuthus

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 selectively the high conductance calcium-activated (maxi-K) 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 1 subfamily.

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ionic channel inhibitor Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond Pyrrolidone carboxylic acid
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 1.3		PRO_0000044899
Regions
	Region	26 – 33	8	Interaction with Ca(2+)-activated K(+) channels Potential
Amino acid modifications
	Modified residue	1	1	Pyrrolidone carboxylic acid Ref.1
	Disulfide bond	7 ↔ 28		Ref.2
	Disulfide bond	13 ↔ 33		Ref.2
	Disulfide bond	17 ↔ 35		Ref.2

Sequences

	Sequence		Length	Mass (Da)
	P24663-1 [UniParc]. Last modified February 1, 1994. Version 2. Checksum: 012D5EFA710C950E	FASTA	37	4,254
	10 20 30 QFTDVDCSVS KECWSVCKDL FGVDRGKCMG KKCRCYQ

References

[1]	"Purification and characterization of a unique, potent, peptidyl probe for the high conductance calcium-activated potassium channel from venom of the scorpion Buthus tamulus." Galvez A., Gimenez-Gallego G., Reuben J.P., Roy-Contancin L., Feigenbaum P., Kaczorowski G.J., Garcia M.L. J. Biol. Chem. 265:11083-11090(1990) [PubMed: 1694175] [Abstract] Cited for: PROTEIN SEQUENCE. Tissue: Venom.
[2]	"Determination of the three-dimensional structure of iberiotoxin in solution by 1H nuclear magnetic resonance spectroscopy." Johnson B.A., Sugg E.E. Biochemistry 31:8151-8159(1992) [PubMed: 1381959] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.

Cross-references

Sequence databases
PIR	S32792.
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.
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

KAX13_MESTA

Accession

Primary (citable) accession number: P24663

Entry history

Integrated into UniProtKB/Swiss-Prot:	March 1, 1992
Last sequence update:	February 1, 1994
Last modified:	November 24, 2009
This is version 57 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)