Beta-mammal toxin Css2 (Css2) (Css2)

Beta-mammal toxin Css2 is a potent neurotoxin isolated from the venom of the Mexican scorpion Centruroides suffusus suffusus. It belongs to the beta-class of scorpion toxins, which are characterized by their ability to modulate the gating mechanism of voltage-gated sodium channels (Nav) by binding to neurotoxin receptor site 4 (UniProt P01490). This interaction causes the sodium channels to open at more hyperpolarized membrane potentials, leading to repetitive firing of action potentials and eventual paralysis (Possani et al., 2000). Clinically, Css2 is a primary driver of the severe systemic toxicity observed in scorpion stings, including life-threatening respiratory and cardiovascular complications. While not a traditional therapeutic target for drug development, it is the primary target for neutralization by polyvalent scorpion antivenoms such as Anascorp (FDA/NIH). Additionally, Css2 is utilized as a high-affinity ligand in research to study the structural biology and electrophysiology of sodium channel subunits. The toxin consists of 66 amino acids and is stabilized by four disulfide bridges, a structural motif common to many scorpion neurotoxins (Cohen et al., 2005). Its high specificity for mammalian sodium channels makes it particularly dangerous to humans but also a precise tool for pharmacological mapping.

Other names

CssIIToxin IICentruroides suffusus suffusus toxin 2Sodium channel modulatory toxin Css2

Css2 binds to neurotoxin receptor site 4 of voltage-gated sodium channels, shifting the activation threshold to more negative potentials and trapping the domain II voltage sensor in an activated state (UniProt P01490, Cohen et al., 2005).