title: Isolation and characterization of Hainantoxin-II, a new neurotoxic peptide from the Chinese bird spider (Haplopelma hainanum).
abstract: Hainantoxin-II (HnTx-II), a novel neurotoxin, was isolated from the venom of the Chinese bird spider (Haplopelma hainanum) by cation exchange chromatography and reverse-phase HPLC. The toxin was a single chain polypeptide with calculated molecular weight of 4 253.135 obtained by mass spectrometry. The complete amino acid sequence of HnTx-II was determined by Edman degradation and found to contain 37 residues with three disulfide bonds. Results showed HnTx-II can reversibly paralyze cockroaches for several hours after intra-abdominal injection with ED50 of 16 ug/g and kill the insects immediately at a dose of 60 ug/g. It was also shown to kill mice at a LD50 value of 1.41ug/g after intracerebroventricular injection. Hainantoxin-II shares 91% sequence homology with Huwentoxin-II (HwTx-II), an insecticidal peptide from another bird spider (Haplopelma schmidti) with a unique scaffold. While HnTx-II and HwTx-II both exhibit toxic activities in insects and mammals, HnTx-II shows higher insecticidal activity and lower lethiferous activity of mammals than HwTx-II. These results help clarify structural-functional relationships of the polypeptide toxin.
authors.affiliation: Zhejiang Sci-Tech University, Hangzhou 310018, China. panjy@zstu.edu.cn
authors.forename: Jian-Yi
authors.initials: JY
authors.lastname: Pan
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003058:Cockroaches; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity; D013111:Spider Venoms / Q000737:chemistry*
chemical_list: D009498:Neurotoxins; D013111:Spider Venoms