Wallace B A, Mao D
Anal Biochem. 1984 Nov 1;142(2):317-28. doi: 10.1016/0003-2697(84)90471-8.
The circular dichroism spectra of membrane suspensions are distorted by differential light scattering and absorption flattening effects, which arise as a consequence of the large size of the membrane particles relative to the wavelength of light and the high concentration of proteins in the membranes. In this paper, the consequences of these phenomena on the protein spectra of large membrane particles are discussed, and methods for eliminating them are examined. The distortions due to differential light scattering are relatively small in membrane systems, and can be compensated for by use of a large detector acceptance angle geometry. Several methods for correcting for differential flattening, which introduces a substantial distortion, have been evaluated, and a new method, the flattening quotient approach, which produces by far the best results, is described. Since the secondary structures calculated from circular dichroism spectra are highly dependent on accurate spectral shape and magnitude, this method for correcting the spectra may find general application in circular dichroism studies of membrane proteins.
膜悬浮液的圆二色光谱会因差分光散射和吸收平坦化效应而发生畸变，这些效应是由于膜颗粒的尺寸相对于光的波长较大以及膜中蛋白质浓度较高而产生的。本文讨论了这些现象对大膜颗粒蛋白质光谱的影响，并研究了消除这些影响的方法。在膜系统中，差分光散射引起的畸变相对较小，可以通过使用大探测器接收角几何结构来补偿。已经评估了几种校正差分平坦化的方法，这种方法会引入相当大的畸变，并且描述了一种新方法——平坦化商数法，该方法产生的结果迄今为止是最好的。由于从圆二色光谱计算出的二级结构高度依赖于准确的光谱形状和幅度，这种校正光谱的方法可能在膜蛋白的圆二色研究中得到广泛应用。
