摘要
Huwentoxin-Ⅰ是一种小分子量的多肽类毒素,它能阻断脊椎动物的神经肌肉接头传递。该毒素分子内含33个氨基酸残基,有三对二硫键。本文报道用圆二色性光谱分析法对该毒素二级结构的测定和分析,并用Creenfield等介绍的方法计算其二级结构中各种成分的含量。结果表明,此多肽分子中,α螺旋约占22—28％,β折叠约占22—35％,而β转角和无规卷曲约占41—49％。实验还表明,此毒素在不同pH条件下的二级结构均比较稳定,将它加热到80℃保温20分钟后再测定其CD光谱,其二级结构成分变化不大。用各种不同的方法对其二级结构进行了预测,结果表明该分子一级结构序列N-末端有一小段β折叠,C-末端有一段α螺旋,分子中部的大部分残基为β转角和无规卷曲构象。
Huwentoxin-I is a low molecular weight peptide toxin which blocks the transmission of neuro-muscular junction of vertebrates. This toxin consists of 33 amino acid residues with three disulphide bonds. The circular dichroism spectra of the toxin in different conditions were measured and analysed. The contents of various secondary structure elements were calculated with the computer program according to the method of Greenfield, 22-28 percent of amino acid residues is in α-belix, 22-35 percent in β-sheet and 41-49 percent in random coil or β turn. Tbe contents of secondary structure elements of tbe toxin were found to be relatively stable under different pH and after heating at 80℃ for 20 min. The investigation with different methods of secondary structure prediction reveals that most part at the middle of the peptide sequence of the toxin is in random coil or β-turn conformation, while a small β-sheet is formed at the N-terminal and an α-helix at the C-terminal.
出处
《北京大学学报（自然科学版）》
CAS
CSCD
北大核心
1993年第6期668-674,共7页
Acta Scientiarum Naturalium Universitatis Pekinensis
关键词
虑纹捕鸟蛛
毒素
二级结构
蜘蛛
Huwentoxin-I
Circular dichroism
Seconday structure prediction
Spider toxin
