Tu A T, Jo B H, Yu N T
Int J Pept Protein Res. 1976;8(4):337-43. doi: 10.1111/j.1399-3011.1976.tb02512.x.
Laser Raman spectra of neurotoxins of Pelamis platurus (yellow-bellied sea snake) and Laticauda semifasciata (broad-banded blue sea snake) were investigated. The amide I band appeared at 1672 cm-1 for both toxins, which presents an indication of anti-parallel beta structure. Since this agrees well with the result from the CD-ORD studies of snake neurotoxin, it was concluded that snake neurotoxins mainly consist of beta structure. The amide III band appeared at 1245 cm-1 for P. platurus toxin and 1248 cm-1 for L. semifasciata toxin. The four disulfide bonds present in the toxin have a very similar geometry. After vigorous heat treatment, the backbone configuration of the toxin molecule basically remained the same although it was partially denatured. The major peak at 512 cm-1 was not altered by the heat treatment but a new shoulder appeared at 546 cm-1. This suggests that a new type of S-S stretching vibration (trans-gauche-trans) was produced as a result of heat treatment. However, the majority of the S-S vibrations remained in the gauche-gauche-gauche orientation. A substantial change in the interactions between a tyrosine aromatic ring and neighboring residues was apparently the alteration caused by the heat treatment.
对扁尾海蛇（黄腹海蛇）和半环扁尾海蛇（宽带蓝海蛇）神经毒素的激光拉曼光谱进行了研究。两种毒素的酰胺I带出现在1672 cm-1处，这表明存在反平行β结构。由于这与蛇神经毒素的圆二色光谱-旋光色散（CD-ORD）研究结果非常吻合，因此得出结论，蛇神经毒素主要由β结构组成。扁尾海蛇毒素的酰胺III带出现在1245 cm-1处，半环扁尾海蛇毒素的酰胺III带出现在1248 cm-1处。毒素中存在的四个二硫键具有非常相似的几何结构。经过剧烈热处理后，毒素分子的主链构型基本保持不变，尽管它部分变性。512 cm-1处的主要峰未因热处理而改变，但在546 cm-1处出现了一个新的肩峰。这表明热处理产生了一种新型的S-S伸缩振动（反式-旁式-反式）。然而，大多数S-S振动仍保持旁式-旁式-旁式取向。热处理显然导致酪氨酸芳香环与相邻残基之间的相互作用发生了实质性变化。
