Properties and amino acid sequence of huwentoxin-I, a neurotoxin purified from the venom of the Chinese bird spider Selenocosmia Huwena

Abstract

S-p. Liang, D-y. Zhang, X. Pan, Q. Chen and P-A. Zhou. Properties and amino acid sequence of huwentoxin-I, a neurotoxin purified from the venom of the Chinese bird spider Selenocosmia huwena. Toxicon31, 969–978, 1993.—By means of reverse phase and ion-exchange high performance liquid chromatography, a neurotoxic peptide named huwentoxin-I was purified from the venom of the Chinese bird spider Selenocosmia huwena. The intraperitoneal and intracisternal ld50 in mice of the toxin were 0.70 mg/kg and 9.40 μg/kg, respectively. This toxin at the concentration of 1 × 10−5g/ml can irreversibly block the neuromuscular transmission of the isolated mouse phrenic nerve-diaphragm preparation in 13.4 ± 1.3 min (mean ± S.D., n = 5). The isoelectric point is 8.95 determined by isoelectric focusing electrophoresis. It consists of 33 amino acids including 6 Cys and 6 Lys determined by amino acid analysis. The complete amino sequence of huwentoxin-I was determined. The N-terminal and C-terminal residues were Ala and Leu, respectively. The primary structure showed partial homology with that of μ-agatoxins from the funnel-web spider Agelenopsis aperta.