Q9TXD1 (KAX24_CENNO) Reviewed, UniProtKB/Swiss-Prot

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	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Ecdysozoa › Panarthropoda › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Centruroides

Protein attributes

Sequence length	38 AA.
Sequence status	Complete.
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	Ion channel impairing toxin Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond
Technical term	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 2.4		PRO_0000044906
Sites
	Site	27	1	Basic residue of the functional dyad By similarity
	Site	36	1	Aromatic residue of the functional dyad By similarity
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 [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] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE, FUNCTION. Tissue: Venom.

Cross-references

3D structure databases
ProteinModelPortal	Q9TXD1.
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...

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:	May 1, 2013
This is version 49 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program