P16341 (KAX51_LEIQH) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin alpha-KTx 5.1 Alternative name(s): Leiurotoxin I Short name=LeTx I Leiurotoxin-1 Scyllatoxin Short name=ScyTx
Organism	Leiurus quinquestriatus hebraeus (Yellow scorpion)
Taxonomic identifier	6884 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Ecdysozoa › Panarthropoda › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Leiurus › Leiurus quinquestriatus

Protein attributes

Sequence length	31 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Blocker for the small conductance calcium-activated potassium channels (SK-Ca); also known as apamine-sensitive potassium channel.
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 5 subfamily.

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ion channel impairing toxin Neurotoxin Potassium channel inhibitor Toxin
PTM	Amidation 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 – 31

31

Potassium channel toxin alpha-KTx 5.1

PRO_0000044924

Amino acid modifications

Modified residue

31

1

Histidine amide Ref.1

Disulfide bond

3 ↔ 21

Ref.2 Ref.4

Disulfide bond

8 ↔ 26

Ref.2 Ref.4

Disulfide bond

12 ↔ 28

Ref.2 Ref.4

Secondary structure

1

.

.

.

.

.

.

.

31

Helix Strand Turn

Details...

Helix

5 – 14

10

Beta strand

18 – 21

4

Beta strand

23 – 29

7

Sequences

	Sequence		Length	Mass (Da)
	P16341 [UniParc]. Last modified April 1, 1990. Version 1. Checksum: BB3183DC5CEA53A7	FASTA	31	3,430
	10 20 30 AFCNLRMCQL SCRSLGLLGK CIGDKCECVK H

References

[1]	"Purification and characterization of a unique, potent inhibitor of apamin binding from Leiurus quinquestriatus hebraeus venom." Chicci G.G., Gimenez-Gallego G., Ber E., Garcia M.L., Winquist R., Cascieri M.A. J. Biol. Chem. 263:10192-10197(1988) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE. Tissue: Venom.
[2]	"Leiurotoxin I (scyllatoxin), a peptide ligand for Ca2(+)-activated K+ channels. Chemical synthesis, radiolabeling, and receptor characterization." Auguste P., Hugues M., Grave B., Gesquiere J.C., Maes P., Tartar A., Romey G., Schweitz H., Lazdunski M. J. Biol. Chem. 265:4753-4759(1990) [PubMed] [Europe PMC] [Abstract] Cited for: SYNTHESIS.
[3]	"Moving pieces in a taxonomic puzzle: venom 2D-LC/MS and data clustering analyses to infer phylogenetic relationships in some scorpions from the Buthidae family (Scorpiones)." Nascimento D.G., Rates B., Santos D.M., Verano-Braga T., Barbosa-Silva A., Dutra A.A.A., Biondi I., Martin-Eauclaire M.-F., De Lima M.E., Pimenta A.M.C. Toxicon 47:628-639(2006) [PubMed] [Europe PMC] [Abstract] Cited for: IDENTIFICATION BY MASS SPECTROMETRY.
[4]	"Solution conformation of leiurotoxin I (scyllatoxin) by 1H nuclear magnetic resonance. Resonance assignment and secondary structure." Martins J.C., Zhang W., Tartar A., Lazdunski M., Borremans F.A.M. FEBS Lett. 260:249-253(1990) [PubMed] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.
+	Additional computationally mapped references.

Cross-references

Sequence databases

PIR

A28805.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1SCY	NMR	-	A	1-31	[»]

ProteinModelPortal

P16341.

SMR

P16341. Positions 2-31.

ModBase

Search...

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Family and domain databases

InterPro

IPR003614. Scorpion_toxin-like.
IPR001947. Scorpion_toxinS_K_inh.
[Graphical view]

Pfam

PF00451. Toxin_2. 1 hit.
[Graphical view]

SUPFAM

SSF57095. SSF57095. 1 hit.

PROSITE

PS01138. SCORP_SHORT_TOXIN. 1 hit.
[Graphical view]

ProtoNet

Search...

Other

EvolutionaryTrace

P16341.

Entry information

Entry name

KAX51_LEIQH

Accession

Primary (citable) accession number: P16341

Entry history

Integrated into UniProtKB/Swiss-Prot:	April 1, 1990
Last sequence update:	April 1, 1990
Last modified:	May 1, 2013
This is version 81 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program