HgeTx1, the first K +-channel specific toxin characterized from the venom of the scorpion Hadrurus gertschi Soleglad
Abstract
A novel toxin was identified, purified and characterized from the venom of the Mexican scorpion Hadrurus gertschi (abbreviated HgeTx1). It has a molecular mass of 3950 atomic mass units (a.m.u.) and contains 36 amino acids with four disulfide bridges established between Cys1–Cys5, Cys2–Cys6, Cys3–Cys7 and Cys4–Cys8. It blocks reversibly the Shaker B K +-channels with a Kd of 52 nM. HgeTx1 shares 60%, 45% and 40% sequence identity, respectively, with Heterometrus spinnifer toxin1 (HsTX1), Scorpio maurus K +-toxin (maurotoxin) and Pandinus imperator toxin1 (Pi1), all four-disulfide bridged toxins. It is 57–58% identical with the other scorpion K +-channel toxins that contain only three disulfide bridges. Sequence comparison, chain length and number of disulfide bridges analysis classify HgeTx1 into subfamily 6 of the α-KTx scorpion toxins (systematic name: α-KTx 6.14).
- Publication:
-
Toxicon
- Pub Date:
- January 2006
- DOI:
- 10.1016/j.toxicon.2006.08.009
- Bibcode:
- 2006Txcn...48.1046S
- Keywords:
-
- Amino acid sequence;
- Hadrurus gertschi;
- HgeTx1;
- K <SUP loc="post">+</SUP>-channel;
- Scorpion toxin;
- Shaker B