Structure And Function Of A Neurotoxic Peptide JZTX-Ⅷ From The The Spider Chilobrachys Jingzhao And The CDNA Cloning Of Two Spider Toxins

Abstract: The spider Chilobrachys jingzhao was identified as a new species of spider in Hainan province of China. The crude venom of the spider C jingzhao contains several classes of neurotoxins, among them, jingzhaotoxin- I ,a calcium channel inactivation inhibitor and jingzhaotoxin-III, a voltage-gated sodium channel inhibitor were intensively studied.A novel neurotoxic peptide, named Jingzhaotoxin-VIII (JZTX-VIII, was purified trough gel filtration, ion exchange chromatography and reverse phase HPLC from the crude venom of the spider C jingzhao . The molecular weight of the peptide was determined as 4329. 37Da by mass spectrometry . The complete cDNA of JZTX-VIII was obtained by the method of RACE (Rapid Amplification of cDNA Ends). The amino acid sequence is NH₂-LFECSFSCDIKKNGKPCK GSGEKKCSGGWRCKMNFCVKV-COOH, which was identified by a combination of automatic Edman degradation and translation of the cDNA sequence. The toxin has 39 amino acid residues containing 6 cysteine residues forming three disulf ide bonds. JZTX-VIII can block the neuromuscular transmission of the isolated mouse phrenic nerve-diaphragm preparation and can inhibit Ca²⁺ channel in DRG cells.