Nöppert A, Gast K, Müller-Frohne M, Zirwer D, Damaschun G
Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
FEBS Lett. 1996 Feb 12;380(1-2):179-82. doi: 10.1016/0014-5793(96)00048-8.
Dynamic light scattering and circular dichroism experiments were performed to determine the compactness and residual secondary structure of reduced and by 6 M guanidine hydrochloride denatured ribonuclease A. We find that reduction of the four disulphide bonds by dithiothreitol at 20 degrees C leads to total unfolding and that a temperature increase has no further effect on the dimension. The Stokes' radius of ribonuclease A at 20 degrees C is R(s) = (1.90 +/- 0.04) nm (native) and R(s) = (3.14 +/- 0.06) nm (reduced-denatured). Furthermore, circular dichroism spectra do not indicate any residual secondary structure. We suggest that reduced-denatured Ribonuclease A has a random coil-like conformation and is not in a compact denatured state.
进行了动态光散射和圆二色性实验，以确定还原型以及经6 M盐酸胍变性的核糖核酸酶A的紧密程度和残余二级结构。我们发现，在20℃下用二硫苏糖醇还原四个二硫键会导致完全展开，并且温度升高对尺寸没有进一步影响。20℃时核糖核酸酶A的斯托克斯半径为R(s) = (1.90 ± 0.04) nm（天然型）和R(s) = (3.14 ± 0.06) nm（还原变性型）。此外，圆二色性光谱未显示任何残余二级结构。我们认为，还原变性的核糖核酸酶A具有随机卷曲状构象，并非处于紧密的变性状态。
