P83244 (KA132_ORTSC) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin alpha-KTx 13.2 Short name=OsK-2 Short name=OsK2
Organism	Orthochirus scrobiculosus (Central Asian scorpion)
Taxonomic identifier	6892 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Ecdysozoa › Panarthropoda › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Orthochirus

Protein attributes

Sequence length	28 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Potent and selective inhibitor of Kv1.2/KCNA2 potassium channels. Ref.1
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Miscellaneous	Does not block Kv1.1/KCNA1 and Kv1.3/KCNA3 potassium channels (Ref.1).
Sequence similarities	Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 13 subfamily.
Mass spectrometry	Molecular mass is 2892.14 Da from positions 1 - 28. Determined by MALDI. Ref.1

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ion channel impairing toxin Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond
Technical term	Direct protein sequencing
Gene Ontology (GO)
Biological_process	cytolysis Inferred from direct assay Ref.1. Source: UniProtKB pathogenesis Inferred from direct assay Ref.1. Source: UniProtKB
Cellular_component	extracellular region Non-traceable author statement. Source: UniProtKB
Molecular_function	potassium channel inhibitor activity Inferred from direct assay Ref.1. Source: UniProtKB
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Peptide	1 – 28	28	Potassium channel toxin alpha-KTx 13.2		PRO_0000044910
Regions
	Region	17 – 24	8	Interaction with Ca(2+)-activated K(+) channels Potential
Sites
	Site	18	1	Basic residue of the functional dyad By similarity
	Site	27	1	Aromatic residue of the functional dyad By similarity
Amino acid modifications
	Disulfide bond	2 ↔ 19		By similarity UniProtKB P40755
	Disulfide bond	6 ↔ 24		By similarity UniProtKB P40755
	Disulfide bond	10 ↔ 26		By similarity

Sequences

	Sequence		Length	Mass (Da)
	P83244 [UniParc]. Last modified October 31, 2003. Version 2. Checksum: A9BD3332061F99E5	FASTA	28	2,901
	10 20 ACGPGCSGSC RQKGDRIKCI NGSCHCYP

References

[1]

"OsK2, a new selective inhibitor of Kv1.2 potassium channels purified from the venom of the scorpion Orthochirus scrobiculosus." Dudina E.E., Korolkova Y.V., Bocharova N.E., Koshelev S.G., Egorov T.A., Huys I., Tytgat J., Grishin E.V. Biochem. Biophys. Res. Commun. 286:841-847(2001) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE, FUNCTION, MASS SPECTROMETRY. Tissue: Venom.

Cross-references

3D structure databases
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
PROSITE	PS01138. SCORP_SHORT_TOXIN. False negative. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

KA132_ORTSC

Accession

Primary (citable) accession number: P83244

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 28, 2002
Last sequence update:	October 31, 2003
Last modified:	April 3, 2013
This is version 43 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program