| Spider venoms contain a variety of neurotoxic peptide components. The amino acid sequences of about 100 kinds of spider toxin have been determined so far. Their molecular weights were varied from 3 to 12KD except for black widow spider toxins, which were high molecular mass types. There were plenty of cysteine residues in their sequences. Toxins from different genus share less sequence homology. They can interact with varying kinds of ion channel, these toxins have appeared broader use in the field of neurobiology and pharmacology.The venom of the bird hunting spider Selenocosmia huwena, with bodysize of 6-9cm, which distributes in southwestern hilly area of China and habitually lives in the holes underground, contains a mixture of compounds with different types of biological activity. Five kinds of neurotoxic toxins huwentoxin- I > huwentoxin- II > huwentoxin-IIK huwentoxin-IV > huwentoxin-V and a lectin-like peptide SHL- I have been isolated by ion exchange chromatography and reverse phase high performance liquid chromatography.A novel neurotoxic peptide, named huwentoxin-VI(HWTX-VI), has been purified from the venom of spider Selenocosmia huwena. The complete amino acid sequence of HWTX-VI was determined as NH2-CIGEG VPCDE NDPRC CSGLV VLKKT LHGIW IKSSY CYKCK-COOH, which consists of 6 Cys formed three disulfidebridges. This 40-residue toxin with molecular weight of 4440.18Da shows little sequence identity with other spider toxins. Another neurotoxic peptide, named Huwentoxin-VH, has been purified from the venom of the same spider. The complete amino acid sequence of HWTX-VII has been determined as NH2-IICAP EGGPC VAGIGCCAGL RCSGA KLGLA GSCQ-COOH, which also consists of 6 Cys formed three pairs of disulfide bridge. This 34-residue toxin withmolecular weight of 3137.22Da can reversibly paralyze mice. |
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