发表机构
Deutsches Elektronen Synchrotron DESY; European XFEL; Max-Planck Institute for the Structure and Dynamics of Matter; Universität Hamburg; University of Melbourne; Arizona State University; University of Washington; National University of Singapore; New York University; Stanford University; SLAC National Accelerator Laboratory; Harvard University; Massachusetts Institute of Technology; Uppsala University; University of Rome Tor Vergata; INFN; Lawrence Berkeley National Laboratory; Royal Melbourne Institute of Technology; University at Buffalo; Ca’ Foscari University of Venice; Swinburne University of Technology; Politecnico di Milano（德国电子同步加速器; 欧洲自由电子激光; 马普物质与结构动力学研究所; 汉堡大学; 墨尔本大学; 亚利桑那州立大学; 华盛顿大学; 新加坡国立大学; 纽约大学; 斯坦福大学; 斯坦福直线加速器中心; 哈佛大学; 麻省理工学院; 乌普萨拉大学; 罗马第二大学; 意大利国家核物理研究所; 劳伦斯伯克利国家实验室; 皇家墨尔本理工大学; 布法罗大学; 威尼斯大学; 斯威本科技大学; 米兰理工大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用X射线自由电子激光实现了对单个巨型血红蛋白红细胞素的飞秒三维成像，分辨率达约20埃，为生物单粒子成像突破辐射损伤限制提供了新途径。
AI 中文摘要
X射线自由电子激光（XFEL）的极强脉冲使人们能够对大分子微晶等辐射敏感样品进行成像，突破了辐射损伤极限。这类光源有望实现生物分子单粒子成像，类似冷冻电镜但无需冷冻固定，且时间分辨率可达飞秒至毫秒级。尽管XFEL建成前就已认识到这一可能性，但此前生物单粒子成像流程仅在大型病毒颗粒上得到验证。基于数十年在X射线束聚焦、颗粒递送、衍射探测及高级分析方面的改进，本研究利用X射线激光脉冲实现了对单个分子复合物——巨型血红蛋白红细胞素（Ery）的成像。衍射图案的二维分类可重构至15埃分辨率，三维图像分辨率约为20埃，而倒易空间中的三维合并强度延伸至超过20埃。分辨率差异可能源于复合物气相压缩导致的异质性。随着通量提升，该方法可用于揭示生物分子质谱研究中的原位结构细节，而样品递送技术的改进或能实现天然状态下生物单粒子的超快快照成像，突破辐射损伤的限制。
英文摘要
The extremely intense pulses of X-ray free-electron lasers (XFELs) have enabled imaging of radiation-sensitive samples, such as macromolecular microcrystals, beyond radiation damage limits. These sources have the potential to deliver biomolecular single-particle imaging, similar to cryo-electron microscopy but without the need for cryo-fixation and with temporal resolution from femtoseconds to milliseconds. While this possibility was recognized before XFELs were built, the biological single-particle imaging work-flow has previously only been demonstrated on large virus particles. Based on decades of improvements in X-ray beam focusing, particle delivery, diffraction detection, and advanced analysis, here we demonstrate imaging of a single molecular complex, the giant-hemoglobin erythrocruorin (Ery) with X-ray laser pulses. Two-dimensional classes of diffraction patterns could be reconstructed to 15 Angstrom resolution, and 3D images to approximately 20 Angstrom, while the 3D merged intensity in reciprocal space extended beyond 20 Angstrom. The resolution discrepancy is likely due to heterogeneity caused by gas-phase compaction of the complexes. With increased throughput, this approach could be used to reveal in-situ structural details during mass spectrometry studies of biomolecules, while improvements in sample delivery may provide ultrafast snapshot imaging of biological single-particles in their native-state beyond the limitations of radiation damage.
