Hongotoxin (HgTX) is an ion channel toxin, which blocks Shaker-type (K<sub>v</sub>1) K<sup>+</sup> channels. The toxin is derived from the venom of Centruroides limbatus, a Central American scorpion found meanly in Costa Rica, Honduras and Panama.
Hongotoxin belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 2 subfamily.
There are five subtypes known of the hongotoxin peptide. HgTX<sub>1</sub> is 39 amino acids long and shows an overall amino acid sequence homology of 89% to margatoxin (MgTX).
Hongotoxin (HgTX) targets are Shaker-type (K<sub>v</sub>1) K<sup>+</sup> channels.
HgTX<sub>1</sub> shows high affinity with K<sub>v</sub>1.1, K<sub>v</sub>1.2, K<sub>v</sub>1.3 voltage-gated potassium channels, but much lower affinity with K<sub>v</sub>1.6 (see table 1 and 2).
HgTX<sub>2</sub>, HgTX<sub>3</sub>, HgTX<sub>4</sub> and HgTX<sub>5</sub> are potent selective inhibitors of Kv1 voltage-gated potassium channels (By similarity).
ND, not determined. All measurements in pM
All measurements in pM
The mode of action is not yet known.