The Structural And Functional Research Of The Toxins From The Venom Of The Spider Macrothele Raveni

Spider venoms are rich sources of novel neurotoxins, which are of interest as tools for studying neurophysiology and as potential lead structure for insecticides and pharmaceuticals. The spider Macrothele raveni was recently identified as a new species of Genus Macrothele. Venom proteins of the spider Macrothele raveni were separated by two-dimensional gel electrophoresis with the separation in the first dimension on a wide range of immobilized pH(3-10) gradients. Also, a mass spectrum of the crude venom from the spider Macrothele raveni was obtained. In addition, five kinds of mammalian neurotoxic peptides were isolated from the crude venom by means of reverse phase and ion-exchange high performance liquid chromatography. Preliminary studies of the biological activity showed that these peptides can cause paralytic damage and rapid respiratory failure in mice, and that large doses can cause death. What is more, a new toxic peptide named Raventoxin-II (雷氏大疣蛛毒素-II) was isolated from the venom of the spider through reverse phase and anion-exchange high performance liquid chromatography. According to its preliminary toxic research, it has been proved that it is a neurotoxin. The exact molecular weight of the toxin is 3021.56Da on the basis of theanalysis of mass spectrum. The amino acid composition analysis suggests that the toxin is composed of 33-amino acid residues including 6 Cys. Furthermore, the amino acid sequence analysis demonstrats that all six Cys residues are involved in disulphide cross-links. The complete amino acid sequence of Raventoxin- II was determined using a Milligen 6625 Prosequencer, the sequence is:H2N-I-C-A-D-E-G-G-P-C-V-A-G-I-G-C-C-A-G-L-R-C-S-G-A-I-L-G-L-A-G-S-C-Q.The amino acid sequence and the biological activites of the toxin show that it is a bioactive peptide different from those of other spiders known so far.