P0CB56 (KAX46_TITST) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin alpha-KTx 4.6 Alternative name(s): Tst26
Organism	Tityus stigmurus (Brazilian scorpion)
Taxonomic identifier	50344 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Ecdysozoa › Panarthropoda › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Tityus

Protein attributes

Sequence length	37 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Blocks potassium channels Kv1.2/KCNA2 and Kv1.3/KCNA3 with high affinity (K(d)=1.9 nM and 10.7 nM, respectively). The voltage-dependent steady-state parameters of potassium channel gating are unaffected by the toxin in both channels, but due to the fast association and dissociation kinetics the toxin slows the rate of inactivation of Kv1.3/KCNA3 channels. Ref.1
Subcellular location	Secreted Ref.1.
Tissue specificity	Expressed by the venom gland. Ref.1
Miscellaneous	This toxin has no effects on Kv1.1/KCNA1, Kv1.4/KCNA4, Kv1.5/KCNA5, Kv11.1/KCNH2, KCa3.1/KCNN4, BK/KCNMA1, and Nav1.5/KCNA5 (Ref.1).
Sequence similarities	Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 4 subfamily.

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	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 4.6		PRO_0000388240
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
	Disulfide bond	7 ↔ 28		By similarity
	Disulfide bond	13 ↔ 33		By similarity
	Disulfide bond	17 ↔ 35		By similarity

Sequences

	Sequence		Length	Mass (Da)
	P0CB56 [UniParc]. Last modified November 3, 2009. Version 1. Checksum: 639B8273B7335929	FASTA	37	3,947
	10 20 30 VFINAKCRGS PECLPKCKQA IGKAAGKCMN GKCKCYP

References

[1]

"Tst26, a novel peptide blocker of Kv1.2 and Kv1.3 channels from the venom of Tityus stigmurus." Papp F., Batista C.V., Varga Z., Herceg M., Roman-Gonzalez S.A., Gaspar R., Possani L.D., Panyi G. Toxicon 54:379-389(2009) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE, MASS SPECTROMETRY, FUNCTION, SUBCELLULAR LOCATION, TISSUE SPECIFICITY. Tissue: Venom.

Cross-references

3D structure databases
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.
ProtoNet	Search...

Entry information

Entry name

KAX46_TITST

Accession

Primary (citable) accession number: P0CB56

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 3, 2009
Last sequence update:	November 3, 2009
Last modified:	May 1, 2013
This is version 10 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program