Reviewed, UniProtKB/Swiss-Prot P59847 (KAX25_CENLM)

Names and origin

Protein names	Recommended name:     Potassium channel toxin alpha-KTx 2.5 Alternative name(s):     Hongotoxin-1       Short name=HgTX1
Organism	Centruroides limbatus (Bark scorpion)
Taxonomic identifier	244936 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Centruroides

Protein attributes

Sequence length	39 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Potent selective inhibitor of Kv1.1, Kv1.2, Kv1.3 voltage-gated potassium channels. Weak inhibitor of Kv1.6 potassium channel. Does not block Kv1.4 and Kv1.5 currents.
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 2 subfamily.
Mass spectrometry	Molecular mass is 4219 Da from positions 1 - 39. Determined by ESI. Ref.2

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 – 39

39

Potassium channel toxin alpha-KTx 2.5

PRO_0000044903

Amino acid modifications

Disulfide bond

7 ↔ 29

Ref.2

Disulfide bond

13 ↔ 34

Ref.2

Disulfide bond

17 ↔ 36

Ref.2

Experimental info

Mutagenesis

19

1

A → C: No loss of activity. Ref.2

Mutagenesis

19

1

A → Y: No loss of activity; when associated with F-37. Ref.2

Mutagenesis

37

1

Y → F: No loss of activity; when associated with Y-19. Ref.2

Secondary structure

1

.

.

.

.

.

.

.

.

.

39

Helix Strand Turn

Details...

Beta strand

8 – 10

3

Helix

11 – 13

3

Helix

14 – 20

7

Beta strand

26 – 30

5

Beta strand

33 – 37

5

Sequences

	Sequence		Length	Mass (Da)
	P59847-1 [UniParc]. Last modified September 19, 2003. Version 1. Checksum: B4ABC83F8EE7E637	FASTA	39	4,226
	10 20 30 TVIDVKCTSP KQCLPPCKAQ FGIRAGAKCM NGKCKCYPH

References

[1]

"Subunit composition of brain voltage-gated potassium channels determined by hongotoxin-1, a novel peptide derived from Centruroides limbatus venom." Koschak A., Bugianesi R.M., Mitterdorfer J., Kaczorowski G.J., Garcia M.L., Knaus H.-G. J. Biol. Chem. 273:2639-2644(1998) [PubMed: 9446567] [Abstract] Cited for: PROTEIN SEQUENCE, MUTAGENESIS, PHARMACOLOGICAL CHARACTERIZATION. Tissue: Venom.

[2]

"Synthesis, characterization, and application of cy-dye- and alexa-dye-labeled hongotoxin(1) analogues. The first high affinity fluorescence probes for voltage-gated K+ channels." Pragl B., Koschak A., Trieb M., Obermair G., Kaufmann W.A., Gerster U., Blanc E., Hahn C., Prinz H., Schuetz G., Darbon H., Gruber H.J., Knaus H.-G. Bioconj. Chem. 13:416-425(2002) [PubMed: 12009929] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS, MASS SPECTROMETRY, MUTAGENESIS OF ALA-19 AND TYR-37. Tissue: Venom.

Cross-references

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1HLY	NMR	-	A	1-39	[»]

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

KAX25_CENLM

Accession

Primary (citable) accession number: P59847

Entry history

Integrated into UniProtKB/Swiss-Prot:	September 19, 2003
Last sequence update:	September 19, 2003
Last modified:	September 1, 2009
This is version 44 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)