Cn2 is a neurotoxin named after and derived from the Centruroides noxius scorpion, which originates from and is endemic in the state of Nayarit, Western Mexico.
CssIV, a β-toxin that shares 57 out of 66 amino acid residues with the Cn2 toxin according to NMR analysis,[12] mainly binds to the extracellular loop between the S3 and S4 segments within the second domain of the target voltage-gated sodium channel.
[2][16] Single-chain variable fragments (scFvs) have been used to recognize and neutralize Cn2 from Centruroides noxius venom.
Specifically, scFv RU1 and LR have shown to complement each other, showing a better neutralization capacity when administered simultaneously.
[17] These two scFvs have affinities in the picomolar range and remove most scorpion toxin poisoning symptoms.