Molecular cloning and primary structure of cDNA fragment for alpha-latrocrustatoxin from black widow spider venom

A fragment of the structural gene of alpha-latrocrustotoxin, a new representative of latrotoxins from black widow spider venom, was cloned. The fragment (1191 bp) was obtained by means of PCR based on the data obtained by sequencing tryptic peptides of the toxin. The fragment codes for a 397-aa sequence. The encoded polypeptide is the C-terminal fragment of the toxin central domain that presumably contains a site responsible for the toxin species specificity. The structural similarity of this fragment to the corresponding fragments of other latrotoxins was studied.