在冷水化生物样本的 X 射线/冷电子显微镜相关研究中,辐射剂量效应
Thorsten B Blum1, Vincent Olieric2, Ana Diaz2
1PSI Center for Life Sciences, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
Acta crystallographica. Section D, Structural biology
|February 26, 2026
概括
暴露于高X射线剂量X射线断层扫描的冷保存样本仍然可以用冷电子显微镜 (cryo-EM) 进行分析,从而产生结构性见解. 这支持用于厚度生物样本分析的集成工作流.
科学领域:
- 结构生物学 结构生物学
- 显微镜技术 显微镜技术
- 生物物理学的生物物理.
背景情况:
- 电子显微镜 (cryo-EM) 提供高分辨率成像,但受样本厚度和视野限制.
- 硬X射线成像可以穿透较厚的样本,为生物样本可视化提供了补充方法.
- 有关冷保存样本的完整性和在同步电机设施中暴露于X射线的辐射损伤存在担忧.
研究的目的:
- 评估X射线曝光对冷保存样品的影响,这对于X射线断层扫描来说是典型的,用于随后的冷EM分析.
- 为了确定高X射线剂量是否会损害样本的完整性,妨碍高分辨率的3D重建.
- 评估整合X射线和冷电磁成像工作流程的可行性.
主要方法:
- 阿波费里丁样品被沉积在冷EM网格上.
- 样品被暴露在各种X射线剂量中,模拟同步 X射线断层扫描条件.
- 暴露的样本随后使用冷-EM进行3D重建进行分析.
主要成果:
- 尽管有明显的辐射损伤,但暴露在高达100MGy的X射线下的样本仍然适用于冷EM分析.
- 即使在高X射线剂量后,结构细节也以大约4 Å的分辨率得到分辨.
- 一个未暴露的apoferritin的冷-EM数据集产生了3.17 Å分辨率的3D重建.
结论:
- 低温X射线断层扫描中的高X射线剂量可能会限制最终分辨率,但不会排除随后的低温EM分析.
- 暴露于高X射线剂量的冷保存生物材料仍然可以在中高分辨率下产生结构生物学见解.
- 这些发现支持集成的X射线和冷EM工作流程,用于对厚型玻璃化生物标本的多尺度分析.
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