Rossmann M G
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1392, USA.
Acta Crystallogr D Biol Crystallogr. 2000 Oct;56(Pt 10):1341-9. doi: 10.1107/s0907444900009562.
Combining X-ray crystallographically determined atomic structures of component domains or subunits with cryo-electron microscopic three-dimensional images at around 22 A resolution can produce structural information that is accurate to about 2.2 A resolution. In an initial step, it is necessary to determine accurately the absolute scale and absolute hand of the cryo-electron microscopy map, the former of which can be off by up to 5%. It is also necessary to determine the relative height of density by using a suitable scaling function. Difference maps can identify, for instance, sites of glycosylation, the position of which helps to fit the component structures into the EM density maps. Examples are given from the analysis of alphaviruses, rhinovirus-receptor interactions and poliovirus-receptor interactions.
将通过X射线晶体学确定的组成结构域或亚基的原子结构与约22埃分辨率的冷冻电子显微镜三维图像相结合，可以产生分辨率精确到约2.2埃的结构信息。在第一步中，有必要准确确定冷冻电子显微镜图谱的绝对比例和绝对手性，前者的误差可能高达5%。还需要使用合适的缩放函数来确定密度的相对高度。例如，差异图谱可以识别糖基化位点，其位置有助于将组成结构拟合到电子显微镜密度图谱中。文中给出了来自甲病毒、鼻病毒-受体相互作用和脊髓灰质炎病毒-受体相互作用分析的示例。
