Baldwin J M, Henderson R, Beckman E, Zemlin F
MRC Laboratory of Molecular Biology, Cambridge, U.K.
J Mol Biol. 1988 Aug 5;202(3):585-91. doi: 10.1016/0022-2836(88)90288-4.
Improvements in technique have produced electron micrographs of purple membrane that provide, after computer analysis, reproducibly measurable diffraction peaks extending to 2.8 A (1 A = 0.1 nm). The improvements include better specimen preparation, a more stable cryo-electron microscope with better alignment and the addition of an image-processing step, which gives weights to local areas of the image according to the local strength of the periodic component of the image. These improvements have enabled the calculation of a directly phased projection map at 2.8 A resolution.
技术的改进产生了紫膜的电子显微照片，经过计算机分析后，可重现地测量到延伸至2.8埃（1埃 = 0.1纳米）的衍射峰。这些改进包括更好的样品制备、一台具有更好校准的更稳定的低温电子显微镜以及增加了一个图像处理步骤，该步骤根据图像中周期性成分的局部强度对图像的局部区域赋予权重。这些改进使得能够计算出分辨率为2.8埃的直接相位投影图。
