Reviewed, UniProtKB/Swiss-Prot P61409 (AF2_GRARO)

Names and origin

Protein names	Recommended name: Kappa-theraphotoxin-Gr2c Short name=Kappa-TRTX-Gr2c Alternative name(s): Mechanotoxin-alpha Peptide GsAF II
Organism	Grammostola rosea (Chilean rose tarantula) (Grammostola spatulata)
Taxonomic identifier	432528 [NCBI]
Taxonomic lineage	Eukaryota › Metazoa › Arthropoda › Chelicerata › Arachnida › Araneae › Mygalomorphae › Theraphosidae › Grammostola

Protein attributes

Sequence length	31 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Binds the voltage-sensor domain of the potassium channel KvAP (from the archaeon Aeropyrum pernix) and affects channel gating By similarity. Blocks mechanosensitive ion channels and the hypotonic cell swelling induced calcium increase associated with the activation of such channels. It can thus be useful in treating cardiac ventricular disturbances. Also induces analgesia in mammals. This analgesia is probably mediated by a non-opioid receptor related mechanism. Ref.1 Ref.2
Subcellular location	Secreted Ref.1 Ref.2.
Tissue specificity	Expressed by the venom gland. Ref.1 Ref.2
Domain	The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin By similarity.
Sequence similarities	Belongs to the phrixotoxin family.
Mass spectrometry	Molecular mass is 3979.9 Da from positions 1 - 31. Determined by ESI. Ref.1 Ref.2

Ontologies

Keywords
Cellular component	Secreted
Domain	Knottin
Molecular function	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: InterPro
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Peptide	1 – 31	31	Kappa-theraphotoxin-Gr2c		PRO_0000045016
Amino acid modifications
	Disulfide bond	2 ↔ 16		By similarity
	Disulfide bond	9 ↔ 21		By similarity
	Disulfide bond	15 ↔ 25		By similarity

Sequences

	Sequence		Length	Mass (Da)
	P61409-1 [UniParc]. Last modified May 24, 2004. Version 1. Checksum: BF03EB84DE1AAC1B	FASTA	31	3,986
	10 20 30 YCQKWMWTCD EERKCCEGLV CRLWCKKKIE W

References

[1]	"Analgesic peptides from venom of Grammostola spatulata and use thereof." Lampe R.A. Patent number US5877026, 02-MAR-1999 Cited for: PROTEIN SEQUENCE, FUNCTION, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, MASS SPECTROMETRY. Tissue: Venom.
[2]	"Antiarrhythmic peptide from venom of spider Grammostola spatulata." Lampe R.A. Patent number US5968838, 19-OCT-1999 Cited for: PROTEIN SEQUENCE, FUNCTION, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, MASS SPECTROMETRY. Tissue: Venom.

Cross-references

3D structure databases
SMR	P61409. Positions 1-30.
ModBase	Search...
Organism-specific databases
ArachnoServer	AS000027. kappa-theraphotoxin-Gr2c.
Family and domain databases
InterPro	IPR011696. Toxin_12. [Graphical view]
Pfam	PF07740. Toxin_12. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

AF2_GRARO

Accession

Primary (citable) accession number: P61409

Entry history

Integrated into UniProtKB/Swiss-Prot:	May 24, 2004
Last sequence update:	May 24, 2004
Last modified:	January 19, 2010
This is version 23 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Tox-Prot (Toxin Annotation Project)