Cloning and sequencing of a fragment of the cDNA for alpha-latrocrustotoxin from black widow spider venom

A fragment of the structural gene of alpha-latrocrustotoxin, a new represen tative of latrotoxins from black widow spider venom, was cloned. The fragme nt (1191 bp) was obtained by means of PCR based on the data obtained by seq uencing tryptic peptides of the toxin. The fragment codes for a 397-aa sequ ence. The encoded polypeptide is the C-terminal fragment of the toxin centr al domain that presumably contains a site responsible for the toxin species specificity. The structural similarity of this fragment to the correspondi ng fragments of other latrotoxins was studied.