OcyKTx2, a new Kâº-channel toxin characterized from the venom of the scorpion Opisthacanthus cayaporum.
Peptides
; 46: 40-6, 2013 Aug.
Article
in En
| MEDLINE
| ID: mdl-23684923
ABSTRACT
Opisthacanthus cayaporum belongs to the Liochelidae family, and the scorpions from this genus occur in southern Africa, Central America and South America and, therefore, can be considered a true Gondwana heritage. In this communication, the isolation, primary structure characterization, and Kâº-channel blocking activity of new peptide from this scorpion venom are reported. OcyKTx2 is a 34 amino acid long peptide with four disulfide bridges and molecular mass of 3807 Da. Electrophysiological assays conducted with pure OcyKTx2 showed that this toxin reversibly blocks Shaker B Kâº-channels with a Kd of 82 nM, and presents an even better affinity toward hKv1.3, blocking it with a Kd of â¼18 nM. OcyKTx2 shares high sequence identity with peptides belonging to subfamily 6 of α-KTxs that clustered very closely in the phylogenetic tree included here. Sequence comparison, chain length and number of disulfide bridges analysis classify OcyKTx2 into subfamily 6 of the α-KTx scorpion toxins (systematic name, α-KTx6.17).
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Peptides
/
Scorpion Venoms
/
Shaker Superfamily of Potassium Channels
/
Kv1.3 Potassium Channel
Limits:
Animals
/
Humans
Language:
En
Journal:
Peptides
Year:
2013
Document type:
Article
Affiliation country:
Brazil