Purification and partial characterization of a novel neurotoxic protein from eggs of black widow spiders (Latrodectus tredecimguttatus).

Up to now, there have been a few reports on the toxic components purified from black widow spider (Latrodectus tredecimguttatus) eggs. In the present study, a novel neurotoxic protein was purified from the eggs by gel filtration combined with ion-exchange chromatography. Its molecular weight was 23.752 kDa determined by electrospray mass spectrometry. The protein could block the neuromuscular transmission in mouse-isolated phrenic nerve-hemidiaphragm preparations completely in a reversible manner and activate tetrodotoxin-sensitive sodium current in rat dorsal root ganglion cells. The N-terminal sequence of the protein was identified by the Edman degradation to be N-S-I-A-D-D-R-Y-R-W-P-G-Y-P-G-A-G-L-I-P-Y-I-I-D-S-. When the sequence was used to search against protein database with a sequence query in Mascot engine there was no matched sequence or protein whereas the Basic Local Alignment Search Tool (BLAST) analysis indicated that no significant similarity was found. These results demonstrated that the protein (named Latroeggtoxin-I) is a novel neurotoxic protein purified from the eggs of black widow spiders.