.1, Two Spider Toxin Structure And Function Of 2,2-d-gel Silver Staining Point Of The Protein Internal Sequence By Edman Degradation Microdetermination Studies

Part I: 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 12 kD 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 channels such as Na+ , K+ and Ca2+. For their selectivity to 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 6-9 cm, 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. Two kinds of neurotoxic toxins huwentoxin-I and huwentoxin-II and a lectin-like peptide SHLP-I have been isolated by ion exchange chromatography and reverse phase high performance liquid chromatography. Recently a new species of spider, which is similar to Selenocosmia huwena morphologically, is found from Tongshe county, Hainan island of south China and is named Selenocosmia hainana. The study of its venom is not reported.A novel neurotoxic peptide, designed huwentoxin-III, has been purified from the venom of spider Selenocosmia huwena. The amino acid sequence has been determined completely as NHi-DCAGY MRECK EKLCC SGYVC SSRWK WCVLP APW-COOH, which consists of 6 Cys formed three pairs of disulfide bridge. This 33-residue toxin with molecular weight of 3853.69 Da shows 60% and 48.5% sequence identity with lectin-like peptide SHL-I previously isolated from the venom of the same spider and the Toxin Protein 5 purified from Mexican red knee tarantula (Brachypelma smithii), respectively. Huwentoxin-III cannot agglutinate human erythrocytes. It can reversibly paralyze cockroaches for several hours, with an ED50 of 192.95+120.84 ug/g (P=0.95) and enhance the muscular contractions by stimulate the never as well as cause spontaneous contractions of the isolated rat vas deferens smooth muscle.Besides, the venom of Selenocosmia hainana have been fractionated by ion exchange chromatography and compared with that of Selenocosmia huwena, the results of which shows evidence difference. The main component of the venom, designed hainantoxin-I, has been purified and its sequence has been determined completely as NH3-ECKGF GKSCV PGKNE CCSGY ACNSR DKWCE VLL-COOH, which contain 6 cysteine formed three pairs of disulfide bridge and shows 51% sequence identity with the huwentoxin-I.