Reviewed, UniProtKB/Swiss-Prot P85529 (KAX2D_CENSU)

Names and origin

Protein names	Recommended name:     Potassium channel toxin alpha-KTx 2.13 Alternative name(s):     Toxin Css20
Organism	Centruroides suffusus suffusus (Mexican scorpion)
Taxonomic identifier	6881 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Centruroides

Protein attributes

Sequence length	38 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Selective inhibitor of voltage-gated potassium channels, blocks the Kv1.2/KCNA2 and Kv1.3/KCNA3 channels with dissociation constants of 1.3 nM and 7.2 nM respectively. Association and dissociation rates of the toxin are slower for Kv1.2 than for Kv1.3. Does not inhibit the potassium channels Kv1.1/KCNA1, Kv1.4/KCNA4, Kv1.5/KCNA5, Kv2.1/KCNB1, Kv11.1/KCNH2, KCa3.1/KCNN4, KCa1.1/KCNMA1 or the sodium channel Nav1.5/SCN5A. Ref.1
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 2 subfamily.
Mass spectrometry	Molecular mass is 4000.3 Da from positions 1 - 38. Determined by ESI. Ref.1

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 – 38	38	Potassium channel toxin alpha-KTx 2.13 Ref.1		PRO_0000358604
Amino acid modifications
	Disulfide bond	7 ↔ 29		By similarity UniProtKB P40755
	Disulfide bond	13 ↔ 34		By similarity UniProtKB P40755
	Disulfide bond	17 ↔ 36		By similarity UniProtKB P40755

Sequences

	Sequence		Length	Mass (Da)
	P85529-1 [UniParc]. Last modified December 16, 2008. Version 1. Checksum: 73672C2B221D74A2	FASTA	38	4,007
	10 20 30 IFINVKCSSP QQCLKPCKAA FGISAGGKCI NGKCKCYP

References

[1]

"A selective blocker of Kv1.2 and Kv1.3 potassium channels from the venom of the scorpion Centruroides suffusus suffusus." Corzo G., Papp F., Varga Z., Barraza O., Espino-Solis P.G., Rodriguez de la Vega R.C., Gaspar R., Panyi G., Possani L.D. Biochem. Pharmacol. 76:1142-1154(2008) [PubMed: 18786511] [Abstract] Cited for: PROTEIN SEQUENCE, FUNCTION, MASS SPECTROMETRY. Tissue: Venom.

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.
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

KAX2D_CENSU

Accession

Primary (citable) accession number: P85529

Entry history

Integrated into UniProtKB/Swiss-Prot:	December 16, 2008
Last sequence update:	December 16, 2008
Last modified:	November 3, 2009
This is version 4 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)