Hainan Tarantula Toxin Structure And Function Of Research And Tiger Analgesic Peptide - I (hwap-i) Of General Pharmacology Studies

Two peptide neurotoxins named Hainantoxin-II (HNTX-II) and Hainantoxin-VI (HNTXI-VI), respectively, were purified from the venom of the Chinese bird spider Selenocosmia hainana by ion exchange chromatography and reverse phase high performance liquid chromatography.HNTX-II can immobilize cockroaches for several hours with ED50 value 16 g/g. At level of 60 g/g, it killed the insect immediately after intra-abdominal injection. The toxin can also kill mice at level of 1.4 g/g after intracerebroventricular injection. The mass spectrometry and amino acid sequence analysis proved that the toxin is a single chain polypeptide with calculated molecular weight 4253.135 Da and complete amino acid sequence of NH2-LFECSVSCEIEKEGNKDCKKKKCKGGWKCKFNMCV KV-COOH. The 37-residue peptide contained 6 cysteines that formed three disulfide bridges. HNTX-II showed high homology with HWTX-II from the venom of Chinese bird spider Selenocosmia huwena, ESTX from the tarantula Eurypelma californicum and venom protein 1 from Mexican red knee tarantula Brachypelma smithii.The molecular weight of HNTX-VI is 3998.49 Da identified by MALDI-TOF mass spectrometry, which is in good agreement with the complete amino acid sequence of NH2-ECKYLWGTCEKDEHCCEHLGCN KKHGWCGWDGTF-COOH, determined by automatic Edman degradation. The neurotoxin can paralyze rat after intracerebroventricular injection and block the neuromuscular transmission of the isolated rat phrenic nerve-diaphragm preparation. The 34-residue peptide, which contained 6 Cys and formed three disulfide bonds, showed high homology with two kinds of K+ channel inhibitor, the HaTx from the venom of the Grammostola spatulata and the SGTxl from the tarantula Scodra griseipes.