Shu Q, Liang S P
Department of Biology, Hunan Normal University, Changsha, People's Republic of China.
J Pept Res. 1999 May;53(5):486-91. doi: 10.1034/j.1399-3011.1999.00039.x.
A neurotoxic peptide, huwentoxin-II (HWTX-II), was purified from the venom of the Chinese bird spider Selenocosmia huwena by ion exchange chromatography and reversed phase HPLC. The toxin can reversibly paralyse cockroaches for several hours, with an ED50 of 127 +/- 54 microg/g. HWTX-II blocks neuromuscular transmission in an isolated mouse phrenic nerve diaphragm preparation and acts cooperatively to potentiate the activity of huwentoxin-I. The complete amino sequence of HWTX-II was determined and found to consist of 37 amino acid residues, including six Cys residues. There is microheterogeneity (Ile/Gln) in position 10, and mass spectrometry indicated that the two isoproteins have a tendency to dimerize. It was determined by mass spectrometry that the six Cys residues are involved in three disulphide bonds. The sequence of HWTX-II is highly homologous with ESTX, a toxin from the tarantula Eurypefina californicum.
一种神经毒性肽，虎纹毒素-II（HWTX-II），通过离子交换色谱法和反相高效液相色谱法从中国鸟蛛虎纹捕鸟蛛的毒液中纯化得到。该毒素能使蟑螂可逆性麻痹数小时，半数有效剂量（ED50）为127±54微克/克。HWTX-II在离体小鼠膈神经膈肌标本中阻断神经肌肉传递，并协同增强虎纹毒素-I的活性。测定了HWTX-II的完整氨基酸序列，发现其由37个氨基酸残基组成，包括6个半胱氨酸残基。第10位存在微异质性（异亮氨酸/谷氨酰胺），质谱分析表明这两种同型蛋白有二聚化的倾向。通过质谱分析确定6个半胱氨酸残基参与形成3个二硫键。HWTX-II的序列与来自加州捕鸟蛛Eurypefina californicum的毒素ESTX高度同源。
