Reviewed, UniProtKB/Swiss-Prot P46114 (KAX41_TITSE)

Names and origin

Protein names	Recommended name:     Potassium channel toxin alpha-KTx 4.1 Alternative name(s):     Tityustoxin K-alpha       Short name=TsTX-K-alpha     TSK4     Toxin II-9
Organism	Tityus serrulatus (Brazilian scorpion)
Taxonomic identifier	6887 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Tityus

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 calcium-activated potassium channels and voltage-gated non-inactivating potassium channels and unblocks inactivating potassium channels blocked by alpha-dendrotoxin in synaptosomes. Binds to a site on the inactivating potassium channel that does not occlude the pore. Its binding apparently prevents alpha-DTX, but not charybdotoxin, from blocking the pore. 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 4 subfamily.

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ionic channel inhibitor Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond
Technical term	3D-structure 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 4.1

PRO_0000044923

Regions

Region

26 – 33

8

Interaction with Ca(2+)-activated K(+) channels Potential

Amino acid modifications

Disulfide bond

7 ↔ 28

Ref.4

Disulfide bond

13 ↔ 33

Ref.4

Disulfide bond

17 ↔ 35

Ref.4

Experimental info

Mutagenesis

27

1

K → A, E or R: Significant loss of affinity for squid Kv1A channel. Ref.4

Secondary structure

1

.

.

.

.

.

.

.

37

Helix Strand Turn

Details...

Helix

10 – 20

11

Beta strand

26 – 29

4

Beta strand

32 – 35

4

Sequences

	Sequence		Length	Mass (Da)
	P46114-1 [UniParc]. Last modified November 1, 1995. Version 1. Checksum: 639B98A977335929	FASTA	37	3,948
	10 20 30 VFINAKCRGS PECLPKCKEA IGKAAGKCMN GKCKCYP

References

[1]	"Tityustoxin K alpha blocks voltage-gated noninactivating K+ channels and unblocks inactivating K+ channels blocked by alpha-dendrotoxin in synaptosomes." Rogowski R.S., Krueger B.K., Collins J.H., Blaustein M.P. Proc. Natl. Acad. Sci. U.S.A. 91:1475-1479(1994) [PubMed: 7509073] [Abstract] Cited for: PROTEIN SEQUENCE, FUNCTION. Tissue: Venom.
[2]	Erratum Rogowski R.S., Krueger B.K., Collins J.H., Blaustein M.P. Proc. Natl. Acad. Sci. U.S.A. 93:12051-12051(1996)
[3]	"The primary structure of noxiustoxin. A K channel blocking peptide, purified from the venom of the scorpion Centruroides noxius Hoffmann." Possani L.D., Martin B.M., Svendsen I. Carlsberg Res. Commun. 47:285-289(1982) Cited for: PROTEIN SEQUENCE OF 1-30. Tissue: Venom.
[4]	"Interaction of a toxin from the scorpion Tityus serrulatus with a cloned K+ channel from squid (sqKv1A)." Ellis K.C., Tenenholz T.C., Jerng H., Hayhurst M., Dudlak C.S., Gilly W.F., Blaustein M.P., Weber D.J. Biochemistry 40:5942-5953(2001) [PubMed: 11352729] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS, MUTAGENESIS OF LYS-27.

Cross-references

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1HP2	NMR	-	A	1-37	[»]

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

KAX41_TITSE

Accession

Primary (citable) accession number: P46114
Secondary accession number(s): P08816

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 1995
Last sequence update:	November 1, 1995
Last modified:	June 16, 2009
This is version 62 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)