Preliminary crystallographic studies of a neurotoxin with a high toxicity from Chinese scorpion Buthus martensii Karsch

Scorpion toxins are a family of small neurotoxic proteins with high selectivity. Gener-ally, most of the toxins are a group of basic homologous polypeptides containing about60—80 amino acids except BmK Ⅳ whose pl is 5.3. It has been reported that theybind to various ion channels with high affinity and selectivity. In spite of the significantsequence similarity found among different toxins, they display various degrees of toxicityand specificity to different animal species. So far they form a good system to study thestructure-function relationship.