Structure The toxin consists of 31 amino acids (ACSRAGENCYKSGRCCDGLYCKAYVVTCYKP). This sequence forms a peptide with a molecular weight of 3.4 kDa. It has six cysteine residues which form three disulphide bonds, between the specific amino acid locations 2&16, 19&21 and 15&28. There is an equal distribution of hydrophilic, hydrophobic and neutral amino acids. Near the C-terminus there is a positively charged surface formed by conserved basic residues, which is thought to interact with an ion channel. The inhibitor cystine knot motif that is formed by the cysteine residues shows analogy to other spider toxins and can also be found in ω-conotoxins, which are present in the venom of cone snails. It has low homology with two peptides: * 47% homology with spider peptide PLTX-II (calcium channel blocker) * 47% homology with conotoxin MrVIB (sodium channel blocker)
Covalitoxin-II
Delta-Palutoxin
Chlorotoxin
Maitotoxin
Toxin
Eoxin
Vomitoxin
Psalmotoxin