Karia Dimple, Koh Adrian F, Yang Wen, Cushing Victoria I, Basanta Benjamin, Mihaylov Daniel B, Khavnekar Sagar, Vyroubal Ondřej, Malínský Miloš, Sháněl Ondřej, Doležal Vojtěch, Plitzko Jürgen, Yu Lingbo, Lander Gabriel C, Aricescu A Radu, Greber Basil J, Kotecha Abhay
Materials and Structural Analysis Division, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 Eindhoven, the Netherlands.
Materials and Structural Analysis Division, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 Eindhoven, the Netherlands.
Structure. 2025 Jul 26. doi: 10.1016/j.str.2025.07.007.
Cryoelectron microscopy (cryo-EM) has transformed structural biology by providing high-resolution insights into biological macromolecules. We report sub-3 Å resolution structures using the 100 keV Tundra cryo-TEM, equipped with the Falcon C direct electron detector (DED). This system combines advanced optics, extreme-brightness field emission gun (XFEG), and SP-TWIN lens to enhance coherence and resolution. The semi-automated loader reduced contamination and drift, enabling extended data collection, while the high detective quantum efficiency (DQE) of Falcon C improved signal-to-noise ratio. We validated performance by determining structures of biological samples, including apoferritin (2.1 Å), T20S proteasome (2.7 Å), GABA receptor (2.8 Å), hemoglobin (5.0 Å), transthyretin (3.5 Å), and AAV9 capsid (2.8 Å), spanning 50 kDa-3.9 MDa. This work highlights the potential of 100 keV transmission electron microscopes (TEMs) to make cryo-EM more accessible. It sets a precedent for using lower voltage TEMs not only for screening, but also for high-resolution protein structure determination.
冷冻电子显微镜（cryo-EM）通过提供对生物大分子的高分辨率洞察，改变了结构生物学。我们报告了使用配备Falcon C直接电子探测器（DED）的100 keV苔原冷冻透射电子显微镜（cryo-TEM）获得的亚3埃分辨率结构。该系统结合了先进的光学元件、极亮场发射枪（XFEG）和SP-TWIN透镜，以增强相干性和分辨率。半自动加载器减少了污染和漂移，实现了长时间的数据采集，而Falcon C的高探测量子效率（DQE）提高了信噪比。我们通过确定生物样品的结构来验证性能，这些样品包括脱铁铁蛋白（2.1埃）、20S蛋白酶体（2.7埃）、GABA受体（2.8埃）、血红蛋白（5.0埃）、转甲状腺素蛋白（3.5埃）和AAV9衣壳（2.8埃），分子量范围从50 kDa到3.9 MDa。这项工作突出了100 keV透射电子显微镜（TEM）使冷冻电子显微镜更易于使用的潜力。它为使用低电压TEM不仅用于筛选，而且用于高分辨率蛋白质结构测定树立了先例。
