P24662 (KAX31_ANDMA) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin alpha-KTx 3.1 Alternative name(s): Kaliotoxin-1 Short name=KTX-1
Organism	Androctonus mauretanicus mauretanicus (Scorpion)
Taxonomic identifier	6860 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Androctonus

Protein attributes

Sequence length	38 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Potent inhibitor of large conductance calcium-activated potassium channels (BK-Ca). Also binds to the dendrotoxin sensitive voltage-dependent potassium channel. It appears to block channel activity by a simple bimolecular inhibition process. Induces a transient period of fast flickering in the channel openings, followed by an almost complete blockade of the channel. Its binding affinity to rat brain synaptosomes is 5-fold higher than this of KTX-3. Binding of the toxin to the channel is associated with significant structural rearrangments in both molecules.
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 3 subfamily.

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ionic channel inhibitor 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 – 38

38

Potassium channel toxin alpha-KTx 3.1

PRO_0000044894

Regions

Region

26 – 33

8

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

Amino acid modifications

Modified residue

38

1

Lysine amide

Disulfide bond

8 ↔ 28

Ref.2 Ref.3 Ref.4 Ref.5

Disulfide bond

14 ↔ 33

Ref.2 Ref.3 Ref.4 Ref.5

Disulfide bond

18 ↔ 35

Ref.2 Ref.3 Ref.4 Ref.5

Secondary structure

1

.

.

.

.

.

.

.

38

Helix Strand Turn

Details...

Turn

11 – 13

3

Turn

15 – 20

6

Beta strand

28 – 31

4

Sequences

	Sequence		Length	Mass (Da)
	P24662 [UniParc]. Last modified February 1, 1995. Version 2. Checksum: E190050E4EA751A5	FASTA	38	4,156
	10 20 30 GVEINVKCSG SPQCLKPCKD AGMRFGKCMN RKCHCTPK

References

[1]	"Kaliotoxin, a novel peptidyl inhibitor of neuronal BK-type Ca(2+)-activated K+ channels characterized from Androctonus mauretanicus mauretanicus venom." Crest M., Jacquet G., Gola M., Zerrouk H., Benslimane A., Rochat H., Mansuelle P., Martin-Eauclaire M.-F. J. Biol. Chem. 267:1640-1647(1992) [PubMed: 1730708] [Abstract] Cited for: PROTEIN SEQUENCE. Tissue: Venom.
[2]	"Kaliotoxin (1-37) shows structural differences with related potassium channel blockers." Fernandez I., Romi R., Szendefi S., Martin-Eauclaire M.-F., Rochat H., van Rietschoten J., Pons M., Giralt E. Biochemistry 33:14256-14263(1994) [PubMed: 7524673] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.
[3]	"3D structure of kaliotoxin: is residue 34 a key for channel selectivity?" Gairi M., Romi R., Fernandez I., Rochat H., Martin-Eauclaire M.-F., van Rietschoten J., Pons M., Giralt E. J. Pept. Sci. 3:314-319(1997) [PubMed: 9262650] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.
[4]	"A concept for rapid protein-structure determination by solid-state NMR spectroscopy." Lange A., Becker S., Seidel K., Giller K., Pongs O., Baldus M. Angew. Chem. Int. Ed. 44:2089-2092(2005) [PubMed: 15744789] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.
[5]	"Toxin-induced conformational changes in a potassium channel revealed by solid-state NMR." Lange A., Giller K., Hornig S., Martin-Eauclaire M.-F., Pongs O., Becker S., Baldus M. Nature 440:959-962(2006) [PubMed: 16612389] [Abstract] Cited for: STRUCTURE BY NMR, DISULFIDE BONDS.
+	Additional computationally mapped references.

Cross-references

Sequence databases

PIR

A42040.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1KTX	NMR	-	A	1-37	[»]
1XSW	NMR	-	A	1-38	[»]
2KTX	NMR	-	A	1-38	[»]
2UVS	NMR	-	A	1-38	[»]
3ODV	X-ray	0.95	A/B	1-38	[»]

ProteinModelPortal

P24662.

SMR

P24662. Positions 1-38.

ModBase

Search...

Protocols and materials databases

StructuralBiologyKnowledgebase

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

KAX31_ANDMA

Accession

Primary (citable) accession number: P24662

Entry history

Integrated into UniProtKB/Swiss-Prot:	March 1, 1992
Last sequence update:	February 1, 1995
Last modified:	November 16, 2011
This is version 74 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program