Howard Hughes Medical Institute, Departments of Biological Chemistry and Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA.
Howard Hughes Medical Institute, Departments of Biological Chemistry and Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA.
Structure. 2020 Apr 7;28(4):458-464.e2. doi: 10.1016/j.str.2020.01.008. Epub 2020 Feb 4.
We previously demonstrated that microcrystal electron diffraction (MicroED) can be used to determine atomic-resolution structures from vanishingly small three-dimensional crystals. Here, we present an example of an experimentally phased structure using only MicroED data. The structure of a seven-residue peptide is solved starting from differences to the diffraction intensities induced by structural changes due to radiation damage. The same wedge of reciprocal space was recorded twice by continuous-rotation MicroED from a set of 11 individual crystals. The data from the first pass were merged to make a "low-dose dataset." The data from the second pass were similarly merged to form a "damaged dataset." Differences between these two datasets were used to identify a single heavy-atom site from a Patterson difference map, and initial phases were generated. Finally, the structure was completed by iterative cycles of modeling and refinement.
我们之前已经证明，微晶体电子衍射（MicroED）可用于从几乎不存在的三维晶体中确定原子分辨率结构。在这里，我们提供了一个仅使用 MicroED 数据进行实验相结构的示例。从由于辐射损伤引起的结构变化引起的衍射强度差异开始，解决了一个七残基肽的结构。通过连续旋转 MicroED 从一组 11 个单个晶体中记录了同一楔形倒易空间两次。将第一次通过的数据合并以形成“低剂量数据集”。将第二次通过的数据同样合并以形成“损坏数据集”。这两个数据集之间的差异用于从 Patterson 差异图中识别单个重原子位置，并生成初始相位。最后，通过建模和精修的迭代循环完成结构。
