Assignment of voltage-gated potassium channel blocking activity to κ-KTx1.3, a non-toxic homologue of κ-hefutoxin-1, from Heterometrus spinifer venom

Scorpion venom components that affect ion-channels function

“…Apparently their interaction with voltage-gated K + channels is similar to α-KTx toxins, consisting of the presence of the a Lys and a hydrophobic residue (mostly Phe or Tyr), that are fully exposed from a flat surfaces and interact with the channel (Srinivasan et al, 2002). Subsequently, the peptide κ-KTx1.3 was isolated and shown to have 60% identity with the κ-KTx1, and had blocking activity on Kv1.1, 1.2 and 1.3 channels (Nirthanan et al, 2005). The κ-KTx2 subfamily is composed by the Om-Toxins (κ-KTx2.1, 2.2, 2.3 and 2.4), OcyC8, OcyC9, HeTx203 and HeTx204.…”

New Tricks of an Old Pattern

“…The last and smallest family, the -KTxs, displays purely helical structure stabilized by two disulfide bridges and fold into an ␣-hairpin fold known as CS␣/␣ (cystine-stabilized helix-loop-helix) (11, 14 -17). Peptides belonging to this family have been isolated from only two scorpion genera: Heterometrus (14,15) and Opisthacanthus (16,17). -KTxs are relatively poor blockers of K ϩ channels, despite presence of the typical functional dyad, Tyr and Lys, important for other activity of the toxin (3).…”

The discovery of a novel snake neurotoxin, candoxin – implications for cholinergic signalling mechanisms in health and disease

“…The isolation and purification of peptide toxins from animal venoms is a well-established, widely utilized and streamlined protocol in our laboratory [19][20][21][22][23] . Lyophilised Malayan krait (Bungarus candidus) venom was subjected to multi-stage high performance liquid chromatography (HPLC) to isolate and purify a novel neurotoxin that was subsequently characterised as candoxin.…”