P46114 (KAX41_TITSE) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin alpha-KTx 4.1 Alternative name(s): TSK4 Tityustoxin K-alpha Short name=TsTX-K-alpha Toxin II-9
Organism	Tityus serrulatus (Brazilian scorpion)
Taxonomic identifier	6887 [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 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.
Domain	Has the structural arrangement of an alpha-helix connected to a beta-sheet by disulfide bonds (CSalpha/beta).
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	3D-structure 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 4.1

PRO_0000044923

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

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 [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] [Europe PMC] [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] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS, MUTAGENESIS OF LYS-27.

Cross-references

3D structure databases

PDBe
RCSB PDB
PDBj

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

ProteinModelPortal

P46114.

SMR

P46114. 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...

Other

EvolutionaryTrace

P46114.

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:	May 1, 2013
This is version 72 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program