P13487 (KAX11_LEIQH) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin alpha-KTx 1.1 Alternative name(s): ChTX-Lq1 ChTx-a Charybdotoxin Short name=ChTX
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	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 (KCa/KCNM), as well as a voltage-dependent potassium channel (Kv1.3/KCNA3). It appears to block channel activity by a simple bimolecular inhibition process. Ref.8 Has a pH-specific antimicrobial activity against bacteria (B.subtilis, E.coli and S.aureus) and the fungus C.albicans. Ref.8
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 1 subfamily.

Ontologies

Keywords
Cellular component	Secreted
Domain	Signal
Molecular function	Antibiotic Antimicrobial Fungicide Ion channel impairing toxin Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond Pyrrolidone carboxylic acid
Technical term	3D-structure Direct protein sequencing
Gene Ontology (GO)
Biological_process	defense response to bacterium Inferred from electronic annotation. Source: UniProtKB-KW defense response to fungus Inferred from electronic annotation. Source: UniProtKB-KW killing of cells of other organism Inferred from electronic annotation. Source: UniProtKB-KW 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

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

Sites

Site

49

1

Basic residue of the functional dyad By similarity

Site

58

1

Aromatic residue of the functional dyad By similarity

Amino acid modifications

Modified residue

23

1

Pyrrolidone carboxylic acid

Disulfide bond

29 ↔ 50

Ref.6 Ref.9 Ref.10 Ref.11 Ref.12 Ref.13 Ref.14

Disulfide bond

35 ↔ 55

Ref.6 Ref.9 Ref.10 Ref.11 Ref.12 Ref.13 Ref.14

Disulfide bond

39 ↔ 57

Ref.6 Ref.9 Ref.10 Ref.11 Ref.12 Ref.13 Ref.14

Secondary structure

1

.

.

.

.

.

.

.

.

59

Helix Strand Turn

Details...

Turn

32 – 37

6

Helix

38 – 42

5

Beta strand

48 – 50

3

Beta strand

52 – 55

4

Sequences

	Sequence		Length	Mass (Da)
	P13487 [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] [Europe PMC] [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] [Europe PMC] [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] [Europe PMC] [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] [Europe PMC] [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] [Europe PMC] [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] [Europe PMC] [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] [Europe PMC] [Abstract] Cited for: IDENTIFICATION BY MASS SPECTROMETRY.
[8]	"Multidimensional signatures in antimicrobial peptides." Yount N.Y., Yeaman M.R. Proc. Natl. Acad. Sci. U.S.A. 101:7363-7368(2004) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[9]	"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] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
[10]	"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] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
[11]	"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] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
[12]	"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] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
[13]	"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] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR OF 23-59, DISULFIDE BONDS.
[14]	"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] [Europe PMC] [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

PDBe
RCSB PDB
PDBj

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

ProteinModelPortal

P13487.

SMR

P13487. Positions 23-59.

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

P13487.

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:	May 1, 2013
This is version 110 of the entry and version 4 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program