Reviewed, UniProtKB/Swiss-Prot P13487 (KAX11_LEIQH)

Names and origin

Protein names	Recommended name:     Potassium channel toxin alpha-KTx 1.1 Alternative name(s):     Charybdotoxin       Short name=ChTX     ChTX-Lq1     ChTx-a
Organism	Leiurus quinquestriatus hebraeus (Yellow scorpion)
Taxonomic identifier	6884 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Leiurus

Protein attributes

Sequence length	59 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Potent selective inhibitor of high conductance (maxi-K), different medium and small conductance calcium-activated potassium channels, as well as a voltage-dependent potassium channel (Kv1.3). It appears to block channel activity by a simple bimolecular inhibition process.
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 1 subfamily.

Ontologies

Keywords
Cellular component	Secreted
Domain	Signal
Molecular function	Ionic channel inhibitor Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond Pyrrolidone carboxylic acid
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

Signal peptide

1 – 22

22

Ref.2 Ref.3 Ref.4

Chain

23 – 59

37

Potassium channel toxin alpha-KTx 1.1

PRO_0000035307

Regions

Region

48 – 55

8

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

Amino acid modifications

Modified residue

23

1

Pyrrolidone carboxylic acid

Disulfide bond

29 ↔ 50

Ref.6 Ref.8 Ref.9 Ref.10 Ref.11 Ref.12 Ref.13

Disulfide bond

35 ↔ 55

Ref.6 Ref.8 Ref.9 Ref.10 Ref.11 Ref.12 Ref.13

Disulfide bond

39 ↔ 57

Ref.6 Ref.8 Ref.9 Ref.10 Ref.11 Ref.12 Ref.13

Secondary structure

1

.

.

.

.

.

.

59

Helix Strand Turn

Details...

Turn

32 – 37

6

Helix

38 – 42

5

Beta strand

52 – 55

4

Sequences

	Sequence		Length	Mass (Da)
	P13487-1 [UniParc]. Last modified November 21, 2003. Version 4. Checksum: 379227EBBCB21947	FASTA	59	6,674
	10 20 30 40 50 MKILSVLLLA LIICSIVGWS EAQFTNVSCT TSKECWSVCQ RLHNTSRGKC MNKKCRCYS

References

[1]	"Dynamic diversification from a putative common ancestor of scorpion toxins affecting sodium, potassium, and chloride channels." Froy O., Sagiv T., Poreh M., Urbach D., Zilberberg N., Gurevitz M. J. Mol. Evol. 48:187-196(1999) [PubMed: 9929387] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Tissue: Single abdominal segment.
[2]	"Purification, sequence, and model structure of charybdotoxin, a potent selective inhibitor of calcium-activated potassium channels." Gimenez-Gallego G., Navia M.A., Reuben J.P., Katz G.M., Kaczorowski G.J., Garcia M.L. Proc. Natl. Acad. Sci. U.S.A. 85:3329-3333(1988) [PubMed: 2453055] [Abstract] Cited for: PROTEIN SEQUENCE OF 23-59.
[3]	"Charybdotoxin is a new member of the K+ channel toxin family that includes dendrotoxin I and mast cell degranulating peptide." Schweitz H., Bidard J.-N., Maes P., Lazdunski M. Biochemistry 28:9708-9714(1989) [PubMed: 2482078] [Abstract] Cited for: PROTEIN SEQUENCE OF 23-59.
[4]	"Analysis of the blocking activity of charybdotoxin homologs and iodinated derivatives against Ca2+-activated K+ channels." Lucchesi K., Ravindran A., Young H., Moczydlowski E. J. Membr. Biol. 109:269-281(1989) [PubMed: 2477548] [Abstract] Cited for: PROTEIN SEQUENCE OF 23-59. Tissue: Venom.
[5]	"Solution synthesis of charybdotoxin (ChTX), a K+ channel blocker." Lambert P., Kuroda H., Chino N., Watanabe T.X., Kimura T., Sakakibara S. Biochem. Biophys. Res. Commun. 170:684-690(1990) [PubMed: 1696475] [Abstract] Cited for: SYNTHESIS OF 23-59.
[6]	"Synthesis and structural characterization of charybdotoxin, a potent peptidyl inhibitor of the high conductance Ca2(+)-activated K+ channel." Sugg E.E., Garcia M.L., Reuben J.P., Patchett A.A., Kaczorowski G.J. J. Biol. Chem. 265:18745-18748(1990) [PubMed: 1699936] [Abstract] Cited for: SYNTHESIS OF 23-59, DISULFIDE BONDS.
[7]	"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: 16551474] [Abstract] Cited for: IDENTIFICATION BY MASS SPECTROMETRY.
[8]	"Molecular structure of charybdotoxin, a pore-directed inhibitor of potassium ion channels." Massefski W. Jr., Redfield A.G., Hare D.R., Miller C. Science 249:521-524(1990) [PubMed: 1696395] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
[9]	"Three-dimensional structure of natural charybdotoxin in aqueous solution by 1H-NMR. Charybdotoxin possesses a structural motif found in other scorpion toxins." Bontems F., Roumestand C., Boyot P., Gilquin B., Doljansky Y. Eur. J. Biochem. 196:19-28(1991) [PubMed: 1705886] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
[10]	"Refined structure of charybdotoxin: common motifs in scorpion toxins and insect defensins." Bontems F., Roumestand C., Gilquin B., Menez A., Toma F. Science 254:1521-1523(1991) [PubMed: 1720574] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
[11]	"Analysis of side-chain organization on a refined model of charybdotoxin: structural and functional implications." Bontems F., Gilquin B., Roumestand C., Menez A., Toma F. Biochemistry 31:7756-7764(1992) [PubMed: 1380828] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
[12]	"Progress in multidimensional NMR investigations of peptide and protein 3-D structures in solution. From structure to functional aspects." Bonmatin J.-M., Genest M., Petit M.-C., Gincel E., Simorre J.-P., Cornet B., Gallet X., Caille A., Labbe H., Vovelle F., Ptak M. Biochimie 74:825-836(1992) [PubMed: 1467342] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
[13]	"NMR solution structure of a two-disulfide derivative of charybdotoxin: structural evidence for conservation of scorpion toxin alpha/beta motif and its hydrophobic side chain packing." Song J., Gilquin B., Jamin N., Drakopoulou E., Guenneugues M., Dauplais M., Vita C., Menez A. Biochemistry 36:3760-3766(1997) [PubMed: 9092804] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
+	Additional computationally mapped references.

Cross-references

Sequence databases

PIR

A60963. A28202.

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1BAH	NMR	-	A	24-59	[»]
1CMR	NMR	-	A	29-46	[»]
2CRD	NMR	-	A	24-59	[»]

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

KAX11_LEIQH

Accession

Primary (citable) accession number: P13487

Entry history

Integrated into UniProtKB/Swiss-Prot:	January 1, 1990
Last sequence update:	November 21, 2003
Last modified:	June 16, 2009
This is version 94 of the entry and version 4 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)