P86110 (KKX25_OPICY) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names	Recommended name: Potassium channel toxin kappa-KTx 2.5 Alternative name(s): OcyC8 OcyKTx6
Organism	Opisthacanthus cayaporum (South American scorpion)
Taxonomic identifier	573324 [NCBI]
Taxonomic lineage	cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Protostomia › Ecdysozoa › Panarthropoda › Arthropoda › Chelicerata › Arachnida › Scorpiones › Iurida › Scorpionoidea › Hemiscorpiidae › Liochelinae › Opisthacanthus

Protein attributes

Sequence length	70 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Voltage-independently blocks potassium currents on human Kv1.1/KCNA1 (IC50=217 µM), and human Kv1.4/KCNA4 (IC50=71 µM) (expressed in CHO cells). Ref.2
Subcellular location	Secreted Ref.2 Ref.3.
Tissue specificity	Expressed by the venom gland. Ref.2 Ref.3
Miscellaneous	Has no effect on other potassium channels, on sodium channels, on bacterial growth and on smooth muscle tissue (a known assay to identify possible bradykinin-potentiating peptides) (Ref.2).
Sequence similarities	Belongs to the short scorpion toxin superfamily. Potassium channel inhibitor kappa-KTx family. Kappa-KTx 2 subfamily.
Mass spectrometry	Molecular mass is 3132.26 Da from positions 43 - 70. Determined by MALDI. Monoisotopic mass. Ref.2

Ontologies

Keywords
Cellular component	Secreted
Domain	Signal
Molecular function	Ion channel impairing toxin Neurotoxin Potassium channel inhibitor Toxin
PTM	Disulfide bond
Technical term	Direct protein sequencing
Gene Ontology (GO)
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
	Signal peptide	1 – 26	26	Potential
	Propeptide	27 – 42	16			PRO_0000398603
	Peptide	43 – 70	28	Potassium channel toxin kappa-KTx 2.5 Ref.2		PRO_0000398136
Amino acid modifications
	Disulfide bond	46 ↔ 64		By similarity
	Disulfide bond	50 ↔ 60		By similarity
Experimental info
	Sequence conflict	53	1	H → N AA sequence Ref.3

Sequences

	Sequence		Length	Mass (Da)
	P86110 [UniParc]. Last modified October 5, 2010. Version 1. Checksum: 152071A7A97408C5	FASTA	70	7,823
	10 20 30 40 50 60 MESSRKSYVL MLFLAFVIMN VCSVSGEPKD GEIAGFEMEE ARYDACVNAC LEHHPNVREC 70 EEACKNPVPP

References

[1]	"Cloning and characterization of cDNA sequences encoding for new venom peptides of the Brazilian scorpion Opisthacanthus cayaporum." Silva E.C., Camargos T.S., Maranhao A.Q., Silva-Pereira I., Silva L.P., Possani L.D., Schwartz E.F. Toxicon 54:252-261(2009) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Tissue: Venom gland.
[2]	"The new kappa-KTx 2.5 from the scorpion Opisthacanthus cayaporum." Camargos T.S., Restano-Cassulini R., Possani L.D., Peigneur S., Tytgat J., Schwartz C.A., Alves E.M., de Freitas S.M., Schwartz E.F. Peptides 32:1509-1517(2011) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE OF 43-70, FUNCTION, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, SYNTHESIS OF 43-70, DOMAIN, CIRCULAR DICHROISM, MASS SPECTROMETRY. Tissue: Venom.
[3]	"Mass spectrometry analysis, amino acid sequence and biological activity of venom components from the Brazilian scorpion Opisthacanthus cayaporum." Schwartz E.F., Camargos T.S., Zamudio F.Z., Silva L.P., Bloch C. Jr., Caixeta F., Schwartz C.A., Possani L.D. Toxicon 51:1499-1508(2008) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE OF 43-64, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, MASS SPECTROMETRY. Tissue: Venom.

Cross-references

Sequence databases
EMBL GenBank DDBJ	FM998750 mRNA. Translation: CAX51396.1.
3D structure databases
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
ProtoNet	Search...

Entry information

Entry name

KKX25_OPICY

Accession

Primary (citable) accession number: P86110
Secondary accession number(s): C5J892

Entry history

Integrated into UniProtKB/Swiss-Prot:	October 5, 2010
Last sequence update:	October 5, 2010
Last modified:	March 6, 2013
This is version 7 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Animal Toxin Annotation Program