Reviewed, UniProtKB/Swiss-Prot Q9TXD1 (KAX24_CENNO)

Names and origin

Protein names	Recommended name:     Potassium channel toxin alpha-KTx 2.4 Alternative name(s):     Noxiustoxin-2       Short name=NTx-2       Short name=NTx2
Organism	Centruroides noxius (Mexican scorpion)
Taxonomic identifier	6878 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Centruroides

Protein attributes

Sequence length	38 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Blocks voltage-gated non-inactivating potassium channels and unblocks inactivating potassium channels blocked by alpha-dendrotoxin in synaptosomes. Has some paralyzing effect on crickets. Ref.1
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Domain	The N-terminus is probably essential for channel affinity.
Miscellaneous	Is less effective than NTX.
Sequence similarities	Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 2 subfamily.

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ionic channel inhibitor Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond
Technical term	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 – 38	38	Potassium channel toxin alpha-KTx 2.4		PRO_0000044906
Amino acid modifications
	Disulfide bond	7 ↔ 28		By similarity
	Disulfide bond	13 ↔ 33		By similarity
	Disulfide bond	17 ↔ 35		By similarity

Sequences

	Sequence		Length	Mass (Da)
	Q9TXD1-1 [UniParc]. Last modified May 1, 2000. Version 1. Checksum: 64E3A9BA12C8B8BA	FASTA	38	4,189
	10 20 30 TIINEKCFAT SQCWTPCKKA IGSLQSKCMN GKCKCYNG

References

[1]	"Noxiustoxin 2, a novel K+ channel blocking peptide from the venom of the scorpion Centruroides noxius Hoffmann." Nieto A.R., Gurrola G.B., Vaca L., Possani L.D. Toxicon 34:913-922(1996) [PubMed: 8875778] [Abstract] Cited for: PROTEIN SEQUENCE, FUNCTION. Tissue: Venom.

Cross-references

3D structure databases
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

KAX24_CENNO

Accession

Primary (citable) accession number: Q9TXD1

Entry history

Integrated into UniProtKB/Swiss-Prot:	September 26, 2003
Last sequence update:	May 1, 2000
Last modified:	November 24, 2009
This is version 40 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)