Toxin that is lethal to crab (PubMed:16183092). It interacts with divalent metal ions (zinc and nickel) suggesting it may function as a metal ion chelator to regulate metal ion levels or as a metal ion transporter, or that its function is modulated by metal ions. Is not active against any of the voltage-gated potassium and sodium channels tested (PubMed:33387653). In addition, it does not show activity in bacterial and fungal growth inhibitory assays as well as in hemolytic assays (PubMed:33387653). Expressed by acrorhagi. Has the structural arrangement of two alpha-helices stabilized by disulfide bonds (CSalpha/alpha 4(S-S)). LD(50) is 520 ug/kg against crab (P.dehaani). This toxin interacts with divalent metal ions (zinc and nickel). This suggests it may function as a metal ion chelator to regulate metal ion levels or as a metal ion transporter, or that its function is modulated by metal ions. Both Thr-23-Pro-24 and Cys-69-Pro-70 are in the trans conformation. Has no activity on human voltage-gated potassium channels Kv1.1/KCNA1, Kv1.2/KCNA2, Kv1.3/KCNA3, Kv11.1/KCNH2/ERG1, KCa1.1/KCNMA1 and KCa3.1/KCNN4, and the human sodium channel Nav1.4/SCN4A. Belongs to the Acrorhagin I family.