Isolation and identification of a sodium channel-inhibiting protein from eggs of black widow spiders.

Abstract: The eggs of black widow spider (L. tredecimguttatus) have been demonstrated to be rich in biologically active components that exhibit great research value and application foreground. In the present study, a protein toxin, named Latroeggtoxin-II, was isolated from the eggs using the combination of gel filtration, ion exchange chromatography and reversed-phase high performance liquid chromatography. Electrospray mass spectrometric analysis indicated that the molecular weight of the protein was 28.69kDa, and Edman degradation revealed that its N-terminal sequence was ESIQT STYVP NTPNQ KFDYE VGKDY—. After being abdominally injected into mice and P. americana, the protein could make the animals especially P. americana display a series of poisoning symptoms. Electrophysiological experiments demonstrated that the protein could selectively inhibit tetrodotoxin-resistant Na+ channel currents in rat dorsal root ganglion neurons, without significant effect on the tetrodotoxin-sensitive Na+ channel currents. Using multiple proteomic strategies, the purified protein was shown to have only a few similarities to the existing proteins in the databases, suggesting that it was a novel protein isolated from the eggs of black widow spiders. [Copyright &y& Elsevier]