P0C164 (KAX2B_CENEL) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin alpha-KTx 2.11 Alternative name(s): Toxin Ce4
Organism	Centruroides elegans (Bark scorpion)
Taxonomic identifier	217897 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Scorpiones › Buthida › Buthoidea › Buthidae › Centruroides

Protein attributes

Sequence length	39 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Blocks Kv1.3/KCNA3 voltage-gated potassium channels of human T-lymphocytes. Ref.1
Subunit structure	Monomer.
Subcellular location	Secreted.
Tissue specificity	Expressed by the venom gland.
Miscellaneous	Does not inhibit calcium-activated potassium channels (KCa3.1/KCNN4) of human T-lymphocytes. Does not inhibit voltage-gated Shaker potassium channels. Does not inhibit Kv2.1/KCNB1 potassium channels (Ref.1).
Sequence similarities	Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 2 subfamily.
Mass spectrometry	Molecular mass is 4295 Da from positions 1 - 39. Determined by ESI. Ref.1

Ontologies

Keywords
Cellular component	Secreted
Molecular function	Ionic channel inhibitor Neurotoxin Potassium channel inhibitor Toxin
PTM	Amidation 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
	Chain	1 – 39	39	Potassium channel toxin alpha-KTx 2.11		PRO_0000226961
Sites
	Site	28	1	Basic residue of the functional dyad By similarity
	Site	37	1	Aromatic residue of the functional dyad By similarity
Amino acid modifications
	Modified residue	39	1	Isoleucine amide
	Disulfide bond	7 ↔ 29		By similarity
	Disulfide bond	13 ↔ 34		By similarity
	Disulfide bond	17 ↔ 36		By similarity

Sequences

	Sequence		Length	Mass (Da)
	P0C164 [UniParc]. Last modified March 7, 2006. Version 1. Checksum: F1AE524E3BF97E10	FASTA	39	4,302
	10 20 30 TIINVKCTSP KQCLLPCKEI YGIHAGAKCM NGKCKCYKI

References

[1]

"Novel alpha-KTx peptides from the venom of the scorpion Centruroides elegans selectively blockade Kv1.3 over IKCa1 K+ channels of T cells." Olamendi-Portugal T., Somodi S., Fernandez J.A., Zamudio F.Z., Becerril B., Varga Z., Panyi G., Gaspar R., Possani L.D. Toxicon 46:418-429(2005) [PubMed: 16026809] [Abstract] Cited for: PROTEIN SEQUENCE, FUNCTION, MASS SPECTROMETRY. Tissue: Venom.

Cross-references

3D structure databases
ProteinModelPortal	P0C164.
SMR	P0C164. Positions 1-37.
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

KAX2B_CENEL

Accession

Primary (citable) accession number: P0C164

Entry history

Integrated into UniProtKB/Swiss-Prot:	March 7, 2006
Last sequence update:	March 7, 2006
Last modified:	November 16, 2011
This is version 21 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program