Neviani Viviana, Lutz Martin, Oosterheert Wout, Gros Piet, Kroon-Batenburg Loes
Department of Chemistry, Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
IUCrdata. 2022 Sep 23;7(Pt 9):x220852. doi: 10.1107/S2414314622008525. eCollection 2022 Sep.
Remarkable features are reported in the diffraction pattern produced by a crystal of the second extracellular domain of tetraspanin CD9 (deemed CD9), the structure of which has been described previously [Oosterheert (2020 ▸), , , e202000883]. CD9 crystallized in space group 1 and was twinned. Two types of diffuse streaks are observed. The stronger diffuse streaks are related to the twinning and occur in the direction perpendicular to the twinning interface. It is concluded that the twin domains scatter coherently as both Bragg reflections and diffuse streaks are seen. The weaker streaks along are unrelated to the twinning but are caused by intermittent layers of non-crystallographic symmetry related molecules. It is envisaged that the raw diffraction images could be very useful for methods developers trying to remove the diffuse scattering to extract accurate Bragg intensities or using it to model the effect of packing disorder on the molecular structure.
跨膜4超家族蛋白CD9（简称CD9）第二个胞外域的晶体所产生的衍射图谱具有显著特征，其结构先前已有描述[奥斯特赫特（2020▸），，，e202000883]。CD9在空间群1中结晶且存在孪晶现象。观察到两种类型的漫散射条纹。较强的漫散射条纹与孪晶有关，出现在垂直于孪晶界面的方向。结论是，由于同时观察到了布拉格反射和漫散射条纹，孪晶域相干散射。沿方向的较弱条纹与孪晶无关，而是由非晶体学对称相关分子的间歇性层引起的。可以设想，原始衍射图像对于试图去除漫散射以提取准确布拉格强度或用其模拟堆积无序对分子结构影响的方法开发者非常有用。
