Aird S D, Middaugh C R, Kaiser I I
Department of Molecular Biology, University of Wyoming, Laramie 82071.
Biochim Biophys Acta. 1989 Aug 31;997(3):219-23. doi: 10.1016/0167-4838(89)90190-8.
Spectroscopic behavior of textilotoxin, from the venom of Pseudonaja t. textilis, and its subunits were investigated using fluorescence, circular dichroism and Fourier transform infrared spectroscopy. Circular dichroism spectra of the B, C and D subunits indicate considerable similarity in their alpha-helix and beta-sheet contents. By contrast, the A subunit displays significantly more beta-sheet and 'remainder' structure. FTIR spectra confirm conclusions drawn from CD spectra. Fluorescence spectra indicate that, in general, tryptophan residues in the A, B and D subunits are relatively exposed to the solvent. The C subunit exhibits no fluorescence, suggesting a lack of tryptophan. Comparisons of individual subunit spectra with those of the intact toxin suggest that significant changes in secondary structure may occur when the toxin dissociates.
利用荧光、圆二色性和傅里叶变换红外光谱对来自东部拟眼镜蛇（Pseudonaja t. textilis）毒液的类凝血酶毒素及其亚基的光谱行为进行了研究。B、C和D亚基的圆二色光谱表明，它们的α-螺旋和β-折叠含量有相当大的相似性。相比之下，A亚基显示出明显更多的β-折叠和“其余”结构。傅里叶变换红外光谱证实了从圆二色光谱得出的结论。荧光光谱表明，一般来说，A、B和D亚基中的色氨酸残基相对暴露于溶剂中。C亚基没有荧光，表明缺乏色氨酸。将单个亚基光谱与完整毒素的光谱进行比较表明，毒素解离时二级结构可能会发生显著变化。
