P24663 (KAX13_MESTA) Reviewed, UniProtKB/Swiss-Prot

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	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Ecdysozoa › Panarthropoda › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Mesobuthus

Protein attributes

Sequence length	37 AA.
Sequence status	Complete.
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	Ion channel impairing toxin 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: InterPro
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
Sites
	Site	27	1	Basic residue of the functional dyad By similarity
	Site	36	1	Aromatic residue of the functional dyad By similarity
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 [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] [Europe PMC] [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] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.

Cross-references

Sequence databases
PIR	S32792.
3D structure databases
ProteinModelPortal	P24663.
SMR	P24663. Positions 1-37.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
Gene3D	3.30.30.10. 1 hit.
InterPro	IPR003614. Scorpion_toxin-like. IPR001947. Scorpion_toxinS_K_inh. [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]
SUPFAM	SSF57095. SSF57095. 1 hit.
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:	May 1, 2013
This is version 65 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program